WO2021097531A1

WO2021097531A1 - Polyionic corrosion inhibitors

Info

Publication number: WO2021097531A1
Application number: PCT/AU2020/051258
Authority: WO
Inventors: Maria Forsyth; Anthony Emil SOMERS; David Mecerreyes; Esther UDABE
Original assignee: Deakin University; University Of The Basque Country; Basque Center For Macromolecular Design And Engineering, Polymat Fundazioa
Priority date: 2019-11-22
Filing date: 2020-11-20
Publication date: 2021-05-27

Abstract

The present disclosure generally relates to polyionic corrosion inhibitors including polymerizable ionic compounds, and to cured reaction products, compositions, formulations, coatings, and methods of making and use thereof. The present disclosure also relates to a method for inhibiting corrosion on a substrate. The present disclosure provides coatings comprising a polymerizable ionic compound or a cured reaction product thereof, wherein the polymerizable ionic compound comprises optionally polymerizable onium cation groups and optionally polymerizable aromatic carboxylate counter-anion groups.

Description

POLYIONIC CORROSION INHIBITORS

FIELD

The present disclosure generally relates to polyionic corrosion inhibitors, polymerizable ionic compounds, and cured reaction products, compositions, formulations, coatings, and methods of making and use thereof.

BACKGROUND

Corrosion of metals is a significant worldwide problem for various industries. Protective coatings used to prevent corrosion typically provide at least one of barrier protection, sacrificial (galvanic) protection and corrosion inhibition, in which each disrupt the electrochemical reaction causing corrosion. Barrier protection acts to prevent migration of electrolytes, sacrificial pigments corrode preferentially to that of the surface being protected, and corrosion inhibitors act in various mechanisms to prevent corrosion including reactions to passivate metal surfaces by forming thin inert films on metal surfaces. Coating systems may contain various resins, solvents, additives, and/or pigments, that provide corrosion protection to substrates. Coating systems are designed for coating onto substrates to provide a protective layer having good mechanical properties such as adhesion, impact resistance and ductility, and which may also include additional corrosion inhibitors for added corrosion protection. Corrosion inhibitors may be provided as pigments including inorganic pigments, organic pigments and metallic pigments. Inorganic pigments include various metal phosphates, molybdates, and silicates, such as zinc molybdate. Organic pigments include various aromatic acids and carbon based polymers including graphite and conducting polymers such as polyaniline. Metallic pigments include metal salts such as metallic zinc, which typically acts as a sacrificial pigment.

There is a need for alternative or improved corrosion inhibitors and coatings that can provide various desirable properties such as effective corrosion inhibition, mechanical properties, processability, adhesion, and/or antimicrobial resistance. SUMMARY

The present disclosure relates to polyionic corrosion inhibitors, polymerizable ionic compounds, and to cured reaction products, compositions, formulations, coatings, and methods of making and use thereof.

The polymerizable ionic compounds of the present disclosure provide polyionic corrosion inhibitors comprising onium cations and aromatic carboxylate anions. The polymerizable ionic compounds comprise at least one polymerizable group, which can be provided on the onium cation and/or aromatic carboxylate anion. The aromatic carboxylate groups provide counter anions for the onium cations of the polymerizable ionic compounds, and have been found effective for providing polymerizable ionic compounds and cured reaction products thereof in the form of polyionic corrosion inhibitors that provide various properties including corrosion inhibition. At least according to some embodiments and examples, the polymerizable ionic compounds or polyionic corrosion inhibitors can be provided as polymerizable ionic liquids or polyionic liquids.

In one aspect, there is provided a method for inhibiting corrosion on a substrate by providing one or more coatings on the substrate, wherein at least one coating comprises a polymerizable ionic compound (PIC) or a cured reaction product thereof, and wherein the PIC comprises onium cation groups and aromatic carboxylate counter anion groups.

In another aspect, there is provided use of a coating comprising a polymerizable ionic compound (PIC) or a reaction product thereof for inhibiting corrosion on a substrate, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups.

In another aspect, there is provided a coated metal substrate comprising a metal substrate coated with one or more coating layers, wherein at least one of the coating layers comprises a polymerizable ionic compound (PIC) or a reaction product thereof, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups.

In another aspect, there is provided a coating applied to an optionally coated substrate, wherein the coating comprises or consists of:

(a) at least one polymerizable ionic compound (PIC) or any reaction product thereof according to any aspects, embodiments or examples as described herein; and

(b) optionally one or more additives selected from a solvent, a curing agent, an adhesion promoter, an inorganic filler, a wetting agent, and an organic crosslinker. In another aspect, there is provided a coating system comprising:

(i) an optionally coated metal substrate;

(ii) one or more optional post coating layers; and

(iii) one or more corrosion protection layers located between (i) and (ii) comprising a polymerizable ionic compound (PIC) or a reaction product thereof, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups.

In another aspect, there is provided a polymerizable ionic compound (PIC) or reaction product thereof comprising or consisting of an optionally polymerizable aromatic carboxylate of Formula 1 and an optionally polymerizable onium cation:

Formula 1 wherein

X is an optionally linked carboxylate anion group; and

R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)- heteroalkenyl, and a polymerizable group.

In an embodiment, the optionally polymerizable onium cations are optionally polymerizable quaternary onium cations. The onium cations may be selected from ammonium cation groups, pyridinium cation groups, imidazolium cation groups, pyrazolium cation groups, pyrrolidinium cation groups, and phosphonium cation groups, which may be optionally polymerizable. In another embodiment, the optionally polymerizable onium cations are optionally polymerizable quaternary ammonium cations.

In one embodiment, the polymerizable ionic compound is a polymerizable ionic liquid (PIL).

In another embodiment, the polymerizable group is selected from an epoxy, acrylamide, acrylate, and vinyl. In another embodiment, the onium cation groups are optionally polymerizable ammonium cation groups of Formula 2a.

Formula 2a wherein

R⁶, R⁷, R⁸, and R⁹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl, and wherein at least one of R⁶, R⁷, R⁸, and R⁹, is a polymerizable group.

In another aspect, there is provided a curable coating composition comprising or consisting of an organic film former, wherein the organic film former comprises or consists of a polymerizable ionic compound (PIC) or a cured reaction product thereof, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups, and wherein at least one polymerizable group is provided on at least one group selected from the onium cation groups and aromatic carboxylate counter-anion groups.

In another aspect, there is provided a process for preparing a coating system comprising: applying the PIC, cured reaction product or coating composition according to any aspects, embodiments or examples as described herein, to an optionally coated substrate; and optionally applying one or more post coating layer to the coating present on the optionally coated substrate.

In another aspect, there is provided a compound of Formula la or salt thereof:

Formula 1a wherein

X is a carboxylic acid or carboxylate group; Lx is an optional group being a divalent linking group selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl;

R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, C_1-12alkyl, C_1-12alkenyl, C_1-12heteroalkyl, C_1-12heteroalkenyl, O-C_1-12alkyl, O- C_1-12alkenyl, O-C_1-12heteroalkyl and O-C_1-12heteroalkenyl; with the proviso that R³ is not hydrogen, hydroxyl or methoxyl, when R¹, R², R⁴, and R⁵, are hydrogen and L¹-Z is -CH=CH-C(=O)OH.

Any embodiment herein shall be taken to apply mutatis mutandis to any other embodiment unless specifically stated otherwise.

The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purpose of exemplification only. Functionally-equivalent products, compositions and methods are clearly within the scope of the disclosure, as described herein.

Throughout this specification, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e. one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present disclosure will be further described and illustrated, by way of example only, with reference to the accompanying drawings in which:

Figure 1A-B provide a schematic of a coating preparation on mild steel containing 20 weight % of polymerizable ionic compounds according to some examples of the present disclosure.

Figure 2 is an Electrochemical Impedance Spectra (EIS) for a coated steel specimen immersed in 1M NaCl solution for 24 hours; black - control coating without any polymerizable ionic compounds; red - coating with 20 weight % [p-OHcoum]MA polymerizable ionic compound according to one example of the present disclosure; blue- coating with 20 weight % [p-O(C6H13)coum]MA polymerizable ionic compound according to another example of the present disclosure. Larger impedance signifies greater corrosion inhibition and better barrier properties.

Figures 3A-C show a time evolution of EIS bode plots for control coating and coatings containing 20 weight % [pOHcoum]MA and [pOC6H13]MA polymerizable ionic compounds according to two examples of the present disclosure immersed in NaCl aqueous solution. The highest impedance shown is the coating containing [pOC₆H₁₃]MA polymerizable ionic compound.

Figure 4 shows images of coated specimens after 20hr immersion in NaCl aqueous solutions. Top image with coating containing 20 weight % [p-OHcoum]MA, middle image with coating containing 20 weight % [p-O(C₄H₉)coum]MA, bottom image with coating containing 20 weight % [p-O(C₆H₁₃)coum]MA polymerizable ionic compound according to some examples of the present disclosure

Figure 5A provides a schematic of polymerizable ionic compounds according to some examples of the present disclosure tested in UV cured coatings at a level of 20 weight %.

Figure 5B(i) shows EIS bode impedance plots for UV cured coatings containing 20 weight % of the different polymerizable ionic compounds (PIC) according to some examples of the present disclosure compared with the control coating.

Figure 5B(ii) shows coatings on AS 1020 mild steel containing 20% of [p- 0[C₆H₁₃)coum]MA, [p-O[C6H13)coum]IM, [p-O[C₆H₁₃)coum]AN and [p- 0[C₆H₁₃)coum]PY and control immersed in sodium chloride aqueous solution after 20 h.

Figure 5C shows Nyquist plots after 24 hours immersion of the coatings in NaCl aqueous solution. Same data is provided as the Bode plots in Figure 5B above but in a different format.

Figures 6A & 6B provides a schematic of the preparation (Figure 6A) and EIS bode impedance plots (Figure 6B) for UV cured coatings containing 20 weight % of the anionic polymerizable ionic compound [p-O(MEM)coum] according to one example of the present disclosure compared with the control coating.

Figure 7 provides a representation of an immersion of mild steel 1020 surface in an aqueous solution containing the polymerizable ionic compounds according to some examples of the present disclosure.

Figure 8A shows Tafel plots of AS 1020 mild steel in control and aqueous solutions containing the polymerizable ionic compounds according to some examples of the present disclosure.

Figure 8B shows corrosion potentials (E_corr), corrosion current density (i_corr), Tafel anodic and cathodic slopes (βa and βc) of the control and aqueous solutions containing the polymerizable ionic compounds according to some examples of the present disclosure. Figure 9 shows Nyquist plots for AS 1020 mild steel immersed in the control and aqueous solutions containing the polymerizable ionic compounds according to some examples of the present disclosure after 0 h and 24 h.

Figure 10 shows optical microscopy images and electrochemical impedance spectra for AS 1020 mild steel immersed in the control and aqueous solutions containing the polymerizable ionic compounds according to some examples of the present disclosure up to 24 h.

Figure 11 shows scanning electron microscopy (SEM) images of AS 1020 mild steel after an exposure of 24 h in control solution and aqueous solutions containing the polymerizable ionic compounds according to some examples of the present disclosure.

DETAILED DESCRIPTION

The present disclosure describes the following various non-limiting examples, which relate to investigations undertaken to identify alternative and improved polymeric based corrosion inhibitors including polymerizable ionic compounds. The polymerizable ionic compounds, cured reaction products, compositions, coatings, and coated substrates thereof in the present disclosure can provide corrosion inhibition, and in some aspects, embodiments or examples, additional properties such as antimicrobial properties, formulation processability, or improved barrier protection from water. It was surprisingly found that a coating composition comprising a polymeric ionic compound could provide an effective coating on a substrate with properties including at least one of corrosion inhibition, and in some embodiments and examples antimicrobial resistance. The coating compositions and coatings as described herein have been found suitable for various uses, and in particular use in protecting metal based infrastructure and conduits from corrosion in marine environments and/or oil and gas industry.

General Definitions and Terms

In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure.

With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention is limited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

All publications discussed and/or referenced herein are incorporated herein in their entirety.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, compositions, coatings, processes, and coated substrates, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

The term “and/or”, e.g., “X and/or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of lower-numbered item (e.g., a “first” item) and/or a higher-numbered item (e.g., a “third” item). As used herein, the phrase “at least one of’, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, “at least one of’ means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination.

Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 2, 3, 4, 5, 5.5 and 6, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

As used herein “curable” or “cured” is descriptive of a material or composition that has or can be cured (e.g. polymerized or crosslinked) by heating to induce polymerization and/or crosslinking; irradiating with actinic irradiation to induce polymerization and/or crosslinking; and/or by mixing one or more components to induce polymerization and/or crosslinking. "Mixing can be performed, for example, by combining two or more parts and mixing to form a homogeneous composition. Alternatively, two or more parts can be provided as separate layers that intermix (e.g., spontaneously or upon application of shear stress) at the interface to initiate polymerization.

The reference to “substantially free” generally refers to the absence of that compound or component in the composition other than any trace amounts or impurities that may be present, for example this may be an amount by weight % in the total composition of less than about 1%, 0.1%, 0.01%, 0.001%, or 0.0001%. The compositions as described herein may also include, for example, impurities in an amount by weight % in the total composition of less than about 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.01%, 0.001%, or 0.0001%.

The term “(meth)acrylate” refers to acrylate, methacrylate, or combinations thereof.

The term "(meth)acrylic” refers to acrylic, methacrylic, or combinations thereof.

The term “(meth)acryl refers to acryl, methacryl, or combinations thereof.

The term “alkyl” includes straight-chained, branched, and cyclic alkyl groups and includes both unsubstituted and substituted alkyl groups. Unless otherwise indicated, the alkyl groups typically contain from 1 to 20 carbon atoms. The alkyl groups may for example contain carbon atoms from 1 to 12, 1 to 10, or 1 to 8. The alkyl groups may for example contain carbon atoms from 2 to 12, 2 to 10, or 2 to 8. Examples of “alkyl” as used herein include, but are not limited to, methyl, ethyl, n-propyl. n-butyl, n-pentyl, isobutyl, t-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cyclo heptyl, adamantyl, and norbornyl, and the like. Unless otherwise noted, alkyl groups may be mono- or polyvalent.

As used herein, the terms "halo" or “halogen”, whether employed alone or in compound words such as haloalkyl, means fluorine, chlorine, bromine or iodine.

As used herein, the term “haloalkyl” means an alkyl group having at least one halogen substituent, the terms “alkyl” and “halogen” being understood to have the meanings outlined above. Similarly, the term “monohaloalkyl” means an alkyl group having a single halogen substituent, the term “dihaloalkyl” means an alkyl group having two halogen substituents and the term “trihaloalkyl” means an alkyl group having three halogen substituents. Examples of monohaloalkyl groups include fluoromethyl, chloromethyl, bromomethyl, fluoromethyl, fluoropropyl and fluorobutyl groups; examples of dihaloalkyl groups include difluoromethyl and difluoroethyl groups; examples of trihaloalkyl groups include trifluoromethyl and trifluoroethyl groups.

As used herein, the term “alkenyl” encompasses both straight and branched chain unsaturated hydrocarbon groups with at least one carbon-carbon double bond. Examples of alkenyl groups include ethenyl, propenyl, butenyl, pentenyl and hexenyl. Further examples of alkenyl groups include ethenyl, 1 -propenyl, 2-propenyl and but-2-enyl.

As used herein, the term “alkynyl” encompasses both straight and branched chain unsaturated hydrocarbon groups with at least one carbon-carbon triple bond. Examples of alkynyl groups include ethynyl, propynyl, butynyl, pentynyl and hexynyl. Further examples of alkynyl groups include ethynyl, 1 -propynyl and 2-propynyl.

The term "heteroalkyl” includes both straight-chained, branched, and cyclic alkyl groups interrupted with one or more heteroatoms (e.g. 1-3) independently selected from S, O, and N. The heteroalkyl may be unsubstituted or substituted. Unless otherwise indicated, the heteroalkyl groups typically contain from 1 to 20 carbon atoms. The heteroalkyl groups may for example contain carbon atoms from 1 to 12, 1 to 10, or 1 to 8. The heteroalkyl groups may for example contain carbon atoms from 2 to 12, 2 to 10, or 2 to 8. Examples of “heteroalkyl” as used herein include, but are not limited to, methoxy, ethoxy, propoxy, 3,6-dioxaheptyl, 3-(trimethylsilyl)-propyl, 4- dimethylaminobutyl, and the like. Unless otherwise noted, heteroalkyl groups may be mono-, di- or polyvalent.

The term “heteroarylalkyl” means a group comprising a heteroaryl and alkyl according to the meanings and any examples independently thereof as described herein.

The term "heteroalkenyl” includes both straight-chained, branched, and cyclic alkenyl groups as described herein with one or more heteroatoms (e.g. 1-3) independently selected from S, O, and N with both unsubstituted and substituted alkenyl groups. Unless otherwise indicated, the heteroalkenyl groups typically contain from 1 to 20 carbon atoms. The heteroalkenyl groups may for example contain carbon atoms from 1 to 12, 1 to 10, or 1 to 8. Unless otherwise noted, heteroalkenyl groups may be mono- or polyvalent.

As used herein, the terms "carbocyclic" and "carbocyclyl" represent a ring system wherein the ring atoms are all carbon atoms, e.g., from 3 to 20 carbon ring atoms, and which may be aromatic, non-aromatic, saturated, or unsaturated. The terms encompass single ring systems, e.g. cycloalkyl groups such as cyclopentyl and cyclohexyl, aromatic groups such as phenyl, and cycloalkenyl groups such as cyclohexenyl, as well as fused- ring systems such as naphthyl and fluorenyl.

As used herein, the terms “heterocyclic’ and “heterocyclyl” represent an aromatic or a non-aromatic cyclic group of carbon atoms wherein from one to three of the carbon atoms is/are replaced by one or more heteroatoms independently selected from nitrogen, oxygen or sulfur. A heterocyclyl group may, for example, be monocyclic or polycyclic, and contain for example from 3 to 20 ring atoms. In a bicyclic heterocyclyl group there may be one or more heteroatoms in each ring, or only in one of the rings. Examples of heterocyclyl groups include piperidinyl, tetrahydrofuranyl, tetrahydropyranyl, pyridyl, pyrimidinyl and indolyl.

As used herein, the term “cycloalkyl” represents a ring system wherein the ring atoms are all carbon atoms, e.g., from 3 to 20 carbon ring atoms, and which is saturated. A cycloalkyl group can be monocyclic or polycyclic. A bicyclic group may, for example, be fused or bridged. Examples of monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl and cyclopentyl. Other examples of monocyclic cycloalkyl groups are cyclohexyl, cycloheptyl and cyclooctyl. Examples of bicyclic cycloalkyl groups include bicyclo[2.2. l]hept-2-yl.

As will be understood, an “aromatic” group means a cyclic group having 4m+2 p electrons, where m is an integer equal to or greater than E As used herein, "aromatic" is used interchangeably with "aryl" to refer to an aromatic group, regardless of the valency of aromatic group.

As used herein, the terms “aromatic carbocyclyl” or “aromatic carbocycle” represent a ring system which is aromatic and in which the ring atoms are all carbon atoms, e.g. having from 6-14 ring atoms. An aromatic carbocyclyl group may be monocyclic or polycyclic. Examples of aromatic carbocyclyl groups include phenyl, naphthyl and fluorenyl. Polycyclic aromatic carbocyclyl groups include those in which only one of the rings is aromatic, such as for example indanyl.

The term “aryl” or “aromatic” group or moiety includes 6-18 ring atoms and can contain optional fused rings, which may be saturated or unsaturated. Examples of aromatic groups include phenyl, naphthyl, biphenyl, phenanthryl, and anthracyl. The aromatic group may optionally contain 1-3 heteroatoms such as nitrogen, oxygen, or sulfur and can contain fused rings. Examples of aromatic group having heteroatoms include pyridyl, furanyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl, benzofuranyl, and benzthiazolyl. Unless otherwise noted the aromatic group may be mono- or polyvalent. In an example, the “aromatic” group may be a monocyclic aromatic group, for example a benzene group that may be unsubstituted or substituted.

The term “arylalkyl” means a group comprising an aryl and an alkyl according to the meanings and any examples independently thereof as described herein.

As used herein, the terms “aromatic heterocycle” or “aromatic heterocyclyl” represent an aromatic cyclic group of carbon atoms wherein from one to three of the carbon atoms is/are replaced by one or more heteroatoms independently selected from nitrogen, oxygen or sulphur, e.g. having from 5-14 ring atoms. The term “aromatic heterocyclyl” is used interchangeably with ‘heteroaryl”. An aromatic heterocyclyl group may be monocyclic or polycyclic. Examples of monocyclic aromatic heterocyclyl groups (also referred to as monocyclic heteroaryl groups) include furanyl, thienyl, pyrrolyl, imidazolyl, pyridyl and pyrimidinyl. Examples of polycyclic aromatic heterocyclyl groups (also referred to as bicyclic heteroaryl groups) include benzimidazolyl, quinolinyl and indolyl. Polycyclic aromatic heterocyclyl groups include those in which only one of the rings is an aromatic heterocycle.

As used herein, the term "cyano" represents a -CN moiety.

As used herein, the term “hydroxyl” represents a -OH moiety.

As used herein, the term "alkoxy" represents an -O-alkyl group in which the alkyl group is as defined supra. Examples include methoxy, ethoxy, n-propoxy, iso-propoxy, and the different butoxy, pentoxy, hexyloxy and higher isomers.

As used herein, the term "aryloxy" represents an -O-aryl group in which the aryl group is as defined supra. Examples include, without limitation, phenoxy and naphthoxy.

As used herein, the term "carboxyl" represents a -CO2H moiety.

As used herein, the term "nitro" represents a -NO2 moiety.

The term "optionally fused" means that a group is either fused to another ring system or unfused, and “fused” refers to one or more rings that share at least two common ring atoms with one or more other rings. Fusing may be provided by one or more carbocyclic or heterocyclic rings, as defined herein, or be provided by substituents of rings being joined together to form a further ring system. The fused ring may be a 5, 6 or 7-membered ring of between 5 and 10 ring atoms in size. The fused ring may be fused to one or more other rings, and may for example contain 1 to 4 rings.

The term "optionally substituted" means that a functional group is either substituted or unsubstituted, at any available position. The term “substituted” as referred to above or herein may include, but is not limited to, groups or moieties such as halogen, hydroxyl, alkyl, or haloalkyl.

Polymerizable Ionic Compounds (PIC)

The present disclosure provides various polymerizable ionic compounds (PIC) comprising onium cation groups and aromatic carboxylate counter-anion groups. The onium cation groups and aromatic carboxylate counter-anion groups can coordinate to form a polymerizable ionic compound (PIC) or a cured reaction product thereof. It will be appreciated that the polymerizable ionic compound (PIC) or a cured reaction product thereof can be provided as a salt formed from the association of the cation and anion groups. The cured reaction product is also referred to herein as a polymerized ionic compound (PZIC). In other words, the onium cation groups and aromatic carboxylate counter-anion groups can coordinate in the cured polymer PZIC. It will be appreciated that at least one polymerizable group is provided on a group selected from the onium cation groups and aromatic carboxylate counter-anion groups.

In one example, the polymerizable ionic compound (PIC) is a polymerizable ionic liquid (PIL). In another example, the polymerized ionic compound (PZIC) is a polymerized ionic liquid (PZIL).

In another embodiment, the cured reaction product or PZIC can comprise a polymer chain containing a plurality of the onium cation groups covalently linked within and/or along the polymer chain, and wherein the aromatic carboxylate counter-anion groups provide counter-ions for the onium cation groups. In another embodiment, the cured reaction product or PZIC can comprise a polymer chain containing a plurality of the aromatic carboxylate counter-anion groups covalently linked within and/or along the polymer chain, and wherein the onium cation groups provide counter-ions for the aromatic carboxylate counter-anion groups. In another embodiment, the cured reaction product or PZIC can comprise a first polymer chain containing a plurality of the onium cation groups covalently linked within and/or along the first polymer chain, and a second polymer chain containing a plurality of the aromatic carboxylate counter-anion groups covalently linked within and/or along the second polymer chain, and wherein the aromatic carboxylate counter-anion groups provide counter-ions for the onium cation groups.

In another embodiment, the cured reaction product or PZIC can comprise a polymer chain containing a plurality of the onium cation groups covalently linked as individual pendant groups along the polymer chain, and wherein the aromatic carboxylate counter-anion groups provide counter-ions for the onium cation groups. In another embodiment, the cured reaction product or PZIC can comprise a polymer chain containing a plurality of the aromatic carboxylate counter-anion groups covalently linked as individual pendant groups along the polymer chain, and wherein the onium cation groups provide counter-ions for the aromatic carboxylate counter-anion groups. In another embodiment, the cured reaction product or PZIL can comprise a first polymer chain containing a plurality of the onium cation groups covalently linked as individual pendant groups along the first polymer chain, and a second polymer chain containing a plurality of the aromatic carboxylate counter-anion groups covalently linked as individual pendant groups along the second polymer chain, and wherein the onium cation groups provide counter-ions for the aromatic carboxylate counter-anion groups. Onium Cation Groups

The optionally polymerizable onium cations may be optionally polymerizable quaternary onium cations. The optionally polymerizable onium cations may be selected from ammonium cation groups, pyridinium cation groups, imidazolium cation groups, pyrazolium cation groups, pyrrolidinium cation groups, and phosphonium cation groups. In one embodiment, the onium cations do not contain a polymerizable group, such as in some examples when a polymerizable group is provided on an aromatic carboxylate counter-anion group. In another embodiment, the onium cations may be quaternary onium nitrogen cations, for example cations selected from ammonium cation groups, pyridinium cation groups, imidazolium cation groups, pyrazolium cation groups, and pyrrolidinium cation groups. In another embodiment, the onium cations are polymerizable. For example, an onium compound may comprise one or more polymerizable groups according to any embodiments or examples as described herein.

The onium cations may be selected from any of the onium cations of Formula 2a, 2b, 2c, or 2d:

Formula 2a Formula 2b Formula 2c Formula 2d wherein

R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, and a polymerizable group, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, are optionally substituted with one or more hydroxyl groups.

In one example, the onium cations of Formula 2a, 2b, 2c, or 2d, are quaternary onium cations. For example, R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, may be each independently selected from alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, and a polymerizable group.

In another example of any of the onium cations of Formula 2a, 2b, 2c, or 2d, the groups R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, and a polymerizable group. In another example, R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, and heteroalkyl, and a polymerizable group. In a further example, at least one of R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, is a polymerizable group. In a further example, one of R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, is a polymerizable group.

In another example of any of the onium cations of Formula 2a, 2b, 2c, or 2d, the groups R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and heteroarylalkyl. In another example, the groups R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl. In another example, R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, and heteroalkyl.

In one embodiment, the onium cations are selected from onium nitrogen cations of Formula 2a:

Formula 2a wherein

A is a polymerizable group selected from an optionally linked epoxy, acrylamide, acrylate, and vinyl group; and

R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and heteroarylalkyl, wherein two or more groups may join together to provide an aromatic or aliphatic ring, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and heteroarylalkyl, are optionally substituted with one or more hydroxyl groups.

In some examples of Formula 2a, A may be an aryl comprising a polymerizable group. In further examples of any of the onium cations of Formula 2a, the groups R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, and aryl. In another example, R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, heteroalkyl, and aryl. In another example, R⁶, R⁷, and R⁸, are each independently selected from hydrogen and alkyl. In another example, R⁶ and R⁷ are each independently selected from hydrogen and alkyl, and R⁸ is an optionally substituted aryl. In one example, the onium cation of Formula 2a is cetrimonium. In another embodiment, the onium cations are selected from onium nitrogen cations of Formula 2b:

Formula 2b wherein

R⁶, R⁷, R⁸, R⁹, and R¹⁰, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, and a polymerizable group, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, are optionally substituted with one or more hydroxyl groups.

In some examples of any of the onium cations of Formula 2b, the groups R⁶, R⁷, R⁸, R⁹, and R¹⁰, are each independently selected from hydrogen, alkyl, heteroalkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2b, the groups R⁶, R⁷, R⁸, R⁹, and R¹⁰, are each independently selected from hydrogen, alkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2b, the groups R⁶, R⁷, R⁹, and R¹⁰, are each selected from hydrogen and alkyl, and R⁸ is a polymerizable group. In some examples of any of the onium cations of Formula 2b, the groups R⁶, R⁷, R⁸, R⁹, and R¹⁰, are each independently selected from hydrogen and alkyl. The alkyl and heteroalkyl groups may be optionally substituted with hydroxyl.

In another embodiment, the onium cations are selected from quaternary onium nitrogen cations of Formula 2c:

Formula 2c wherein R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, and a polymerizable group, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, are optionally substituted with one or more hydroxyl groups.

In some examples of any of the onium cations of Formula 2c, the groups R⁶, R⁷, R⁸, R⁹, and R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, heteroalkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2c, the groups R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen, alkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2c, the groups R⁶, R⁷, R⁸, R⁹, and R¹⁰, are each selected from hydrogen and alkyl, and R¹¹ is a polymerizable group. In some examples of any of the onium cations of Formula 2c, the groups R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹, are each independently selected from hydrogen and alkyl. The alkyl and heteroalkyl groups may be optionally substituted with hydroxyl.

In another embodiment, the onium cations are selected from quaternary onium nitrogen cations of Formula 2d:

Formula 2d wherein

R⁶, R⁷, R⁸, and R⁹, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, and a polymerizable group, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, are optionally substituted with one or more hydroxyl groups.

In some examples of any of the onium cations of Formula 2d, the groups R⁶, R⁷, R⁸, and R⁹, are each independently selected from hydrogen, alkyl, heteroalkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2d, the groups R⁶, R⁷, R⁸, and R⁹, are each independently selected from hydrogen, alkyl, and a polymerizable group. In some examples of any of the onium cations of Formula 2d, the groups R⁶, R⁷, and R⁹, are each selected from hydrogen and alkyl, and R⁸ is a polymerizable group. In some examples of any of the onium cations of Formula 2d, the groups R⁶, R⁷, R⁸, and R⁹, are each independently selected from hydrogen and alkyl. The alkyl and heteroalkyl groups may be optionally substituted with hydroxyl.

The following Table 1 provides some further examples of cations, which may be provided with any other anion as described herein for forming a PIC of the present disclosure:

Table 1: Cation Examples

Polymerizable Groups

A polymerizable group (Pz) may be provided on the onium cation groups and/or aromatic carboxylate counter-anion groups. A reference to “optionally polymerizable” refers to a cation and/or anion group that may or may not have a polymerizable group as a substituent thereon according to any embodiments or examples as described herein. One or more polymerizable groups may be provided on the same group, which may for example have two separate substituents selected from a polymerizable group. In one example, the onium cation groups comprise a polymerizable group, and the aromatic carboxylate counter-anion groups do not comprise a polymerizable group. In another example, the aromatic carboxylate counter-anion groups comprise a polymerizable group, and the onium cation groups do not comprise a polymerizable group.

The polymerizable groups (Pz) may be selected from an epoxy, acrylamide, acrylate, and vinyl. The polymerizable groups may be an unsaturated ethylene group, for example a group comprising a terminal vinyl group (e.g. styrene). The vinyl groups (H₂C=CH-) may include vinyl ethers (H₂C=CH-OCH-). The polymerizable groups may include methacryl groups, for example methacrylamide (H₂C=CHCON- or H₂C=C(CH₃)CON-) and meth(acrylate (H₂C=CHCOO- or H₂C=C(CH₃)COO-)). In one embodiment, Pz is a methacrylate group.

The polymerizable group (Pz) may be linked to the cation or anion groups by a divalent linking group (Lz), which for example may be depicted as -Lz-Pz. In one example, the linking groups (Lz) may comprise a group selected from an ester, amide, urea, urethane, ether, carbonate, alkyl, heteroalkyl, aryl, alkylaryl, and heteroaryl. The linking groups may be selected from alkyl and heteroalkyl groups, which may be optionally interrupted by a group selected from an ester, amide, urea, urethane, ether, and carbonate.

Aromatic Carboxylate Groups

It will be appreciated that the aromatic carboxylate group provides a counter anion in the PIC to the cation groups. The aromatic carboxylate group may be an optionally linked, optionally substituted, monocylic or polycyclic aromatic (Ar) group. The counter- anion group may be provided by its respective conjugate acid, which in-situ may form the carboxylate anion. In one example, the aromatic carboxylate group may be provided by a benzene group (Ar) substituted with an optionally linked (L) carboxylate group (- OC(=0) ), which may be referred to by the formulae Ar-C(=O)O- or Ar-L-C(=O)O-. It will be appreciated that the aromatic (Ar) group, for example benzene, may be further optionally substituted at one or more of its ring atoms, such as meta, ortho and/or para substituted with respect to the carboxylate substituent. The aromatic carboxylate group may comprise one or more polymerizable groups according to any embodiments or examples thereof as described herein (e.g. (Pz-Lz)-Ar-C(=O)O-, (Pz-Lz)-Ar-L- C(=O)O-, Pz-Ar-C(=O)O- or Pz-Ar-L-C(=O)O-). For example, an optional substituent of the aromatic group may be a polymerizable group.

In one embodiment, the aromatic carboxylate group is a group of Formula 1:

Formula 1

In the above Formula 1, X is an optionally linked carboxylate group. For example, X may be defined as -Lx-X wherein Lx is an optional linking group and X is the carboxylate anion moiety. R¹ to R⁵ may be each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O- heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)-heteroalkenyl, and a polymerizable group. In another embodiment, the aromatic carboxylate groups may be of Formula la:

Formula 1a

In the above Formula 1a, X is a carboxylate group. Lx is an optional divalent linking group, which may be selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl.

R¹ to R⁵ may be each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)-heteroalkenyl, and a polymerizable group. In one example, for Formula 1 or Formula la, R¹ to R⁵ may be each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O- alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O- C(=0)-heteroalkyl, and O-C(=O)-heteroalkenyl. In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and R², R³, and R⁴, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O- heteroalkyl, and O-heteroalkenyl. In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and at least one of R², R³, and R⁴, is selected from O-alkyl, O- alkenyl, O-heteroalkyl, and O-heteroalkenyl.

In another example, for Formula 1 or Formula la, R¹ to R⁵ may each be independently selected from hydrogen, O-alkyl and O-heteroalkyl, wherein at least one of R², R³, and R⁴, is selected from O-alkyl and O-heteroalkyl. For example, R¹, R², R⁴, and R⁵, can be hydrogen and R³ can be selected from O-alkyl and O-heteroalkyl.

In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and R², R³, and R⁴, are each independently selected from hydrogen and O-C_1-12alkyl, wherein at least one of R², R³, and R⁴, is O-C_1-12alkyl. In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and R², R³, and R⁴, are each independently selected from hydrogen and O-C_2-12alkyl, wherein at least one of R², R³, and R⁴, is selected from O-C_2-12alkyl. In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and R², R³, and R⁴, are each independently selected from hydrogen and O-C_2-8alkyl, wherein at least one of R², R³, and R⁴, is selected from O-C_2-8alkyl. In another example, for Formula 1 or Formula la, R¹ and R⁵ are hydrogen, and R², R³, and R⁴, are each independently selected from hydrogen and O-C3-6alkyl, wherein at least one of R², R³, and R⁴, is selected from O-C3-6alkyl.

In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_1-12alkyl. In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_2-12alkyl. In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_3-6alkyl.

In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O- C(=0)-alkenyl, O-C(=O)-heteroalkyl, and O-C(=O)-heteroalkenyl, and R³ is a polymerizable group. In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are each independently selected from hydrogen and alkyl, and R³ is a polymerizable group. In another example, for Formula 1 or Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is a polymerizable group.

Aromatic Carboxylic Acid and Carboxxlate Compounds

In another aspect, there is provided a compound of Formula la or salt thereof:

Formula 1a wherein

X is a carboxylic acid or carboxylate group;

Lx is an optional divalent linking group selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl;

R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, C_1-12alkyl, C_1-12alkenyl, C_1-12heteroalkyl, C_1-12heteroalkenyl, O-C_1-12alkyl, O- C_1-12alkenyl, O-C_1-12heteroalkyl, O-C_1-12heteroalkenyl, and a polymerizable group.

In another embodiment, there is provided a compound of Formula 1a(i) or salt thereof:

Formula 1 (a)(i) wherein

In an embodiment of Formula la or Formula 1a(i), there is provided a proviso that R³ is not hydrogen, hydroxyl or methoxyl, when R¹, R², R⁴, and R⁵, are hydrogen and L1-Z is -CH=CH-C(=O)OH. In another embodiment of Formula la or Formula 1a(i), R³ is O-C_1-12alkyl, O-C_1-12alkyl, or O-C_3-8alkyl.

In another example, R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, C_1-12alkyl, C_1-12alkenyl, C_1-12heteroalkyl, C_1-12heteroalkenyl, O-C_1-12alkyl, O-C_1-12alkenyl, O-C_1-12heteroalkyl, and O-C_1-12heteroalkenyl.

In another example, for Formula la or Formula 1a(i), R¹ and R⁵ are hydrogen, and at least one of R², R³, and R⁴, is selected from O-C_1-12alkyl. In another example, for Formula la or Formula 1a(i), R¹ and R⁵ are hydrogen, and at least one of R², R³, and R⁴, is selected from O-C_2-12alkyl. In another example, for Formula la or Formula 1a(i), R¹ and R⁵ are hydrogen, and at least one of R², R³, and R⁴, is selected from O-C_2-8alkyl. In another example, for Formula la or Formula 1a(i), R¹ and R⁵ are hydrogen, and at least one of R², R³, and R⁴, is selected from O-C3-6alkyl.

In another example, for Formula la or Formula 1a(i), each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_1-12alkyl. In another example, for Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_2-12alkyl. In another example, for Formula la, each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is O-C_3-6alkyl.

In another example, for Formula 1a(i), each of R¹, R², R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O- C(=0)-alkenyl, O-C(=O)-heteroalkyl, and O-C(=O)-heteroalkenyl, and R³ is a polymerizable group. In another example, for Formula 1a(i), each of R¹, R², R⁴, and R⁵, are each independently selected from hydrogen and alkyl, and R³ is a polymerizable group. In another example, for Formula 1a(i), each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is a polymerizable group.

In another aspect, there is provided an ionic compound of Formula la or salt thereof:

Formula la wherein

X is a carboxylate group;

Lx is an optional linking group selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl;

Y is a cation;

R⁴ and R⁸ are hydrogen;

R⁵, R⁶, and R⁷, are each independently selected from hydrogen, C_1-12alkyl, C_1- ₁₂heteroalkyl, O-C_1-12alkyl, O-C_1-12heteroalkyl, and a polymerizable group.

In another embodiment, there is provided an ionic compound of Formula 1a(i) or salt thereof:

Formula 1 (a)(i) wherein Y is a cation;

It will be appreciated that any of the above embodiments or examples for the carboxylic acid of Formula la or Formula 1a(i) in relation to R¹, R², R³, R⁴, and R⁵, may also apply to the salt form as described above.

In one example, Y is an onium cation. In another example, Y may be selected from any of the onium cations as described herein.

The following Table 2 provides some further examples of carboxylic acids, which may be provided in a carboxylate form and/or used as a counter-anion with any other cation as described herein for forming a PIC of the present disclosure:

Table 2: Aromatic Carboxylic Acid and Carboxylate Examples

Polymerizable Ionic Compounds

In another example, a polymerizable ionic compound (PIC) or reaction product thereof may comprise or consist of optionally polymerizable onium cations and an optionally polymerizable aromatic carboxylate of Formula 1:

Formula 1 wherein

X is a carboxylate anion group;

R¹ and R⁵ are hydrogen; and

R², R³, and R⁴ are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O- heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)- heteroalkenyl, and a polymerizable group. In another example, R² R³, and R⁴ are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)- heteroalkyl, and O-C(=O)-heteroalkenyl.

The polymerizable onium cations for the PIC may be selected from ammonium cation groups, pyridinium cation groups, imidazolium cation groups, pyrazolium cation groups, and pyrrolidinium cation groups. The polymerizable onium cations for the PIC may be selected from polymerizable quaternary onium cations. The polymerizable onium cations for the PIC may be selected from polymerizable quaternary ammonium cations.

In one embodiment, the polymerizable ammonium cation groups for the PIC may be of Formula 2a(i).

wherein

A is an optionally linked polymerizable group;

R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl, wherein each alkyl, alkenyl, heteroalkyl, and heteroalkenyl is optionally substituted, e.g. with halo or hydroxyl groups.

In one embodiment, the polymerizable ammonium cation groups for the PIC may be of Formula 2a(ii)

wherein

are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl, each of which may be optionally substituted, for example with one or more hydroxyl groups;

R^9a is hydrogen or methyl; and n is an integer of 1 to 6, for example an integer of 1 to 3. An organic corrosion inhibitor or ionic compound may be provided according to any combination of “Onium Cation Groups” with “Aromatic Carboxylate Groups” as described individually above for each of those groups.

For example, a corrosion inhibitor may be provided by an ionic compound or cured reaction product thereof formed by an optionally polymerizable aromatic carboxylate counter-anion of Formula 1 and an optionally polymerizable onium cation of Formula 2a as described herein:

Formula 1 Formula 2a

In another example, a coating may be provided comprising a cured reaction product of a polymerizable ionic compound (PIC) comprising an aromatic carboxylate compound of Formula 1 and a polymerizable ammonium compound of Formula 2a(i):

Formula 1 Formula 2a(i)

For the above example, X may be an optionally linked carboxylate anion group; R¹ to R⁵ may each be independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)-heteroalkenyl, and a polymerizable group; A may be an optionally linked polymerizable group; and R⁶, R⁷, and R⁸, may each be independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl. In another example where the onium group is a polymerizable ammonium group, in the cured reaction product the quaternary onium cation groups can be pendant groups along the polymer chain selected from ammonium cation groups of Formula 3:

Formula 3

It will be appreciated that the wavy line indicates a portion of the polymer chain. In the above Formula 3 L² may be an optional divalent linking group to the polymer chain. The divalent linking group may be selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl, for example. R⁶, R⁷, and R⁸, may each be independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl.

The following Table 3 provides further specific examples of cation and anion combinations, which may be provided with each other in forming a PIC of the present disclosure:

Table 3: Examples of Anion and Cation Combinations

In some embodiments, the onium cation is a substituted ammonium cation. The substituted ammonium cation may be provided with a free radically polymerizable group, such as a methacrylate group. In other examples, there is provided polymerizable quaternary onium cations. The polymerizable quaternary onium cations may be selected from ammonium cation groups, imidazolium cation groups, anilinium cation groups, and pyridinium cation groups. The link between the ammonium cation and the methacrylate group may have an ester linkage. In another example of the above Formulae, A is a polymerizable group; R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, and heteroalkenyl. In examples where the cation comprises the polymerizable group, the anion may be absent of a free radically polymerizable group. In another example of the above Formulae, Z is a carboxylate anion group; L¹ is an alkenyl divalent linking group. R¹, R², R⁴ and R⁵ are hydrogen; and R³ may be selected from a hydroxyl or O-alkyl groups, such as butyloxy or hexyloxy groups.

Further examples of free-radically polymerizable monomers of the onium cation with non-polymerizable aromatic carboxylic anion groups include:

In some embodiments, the onium cation, such as a substituted ammonium cation, is absent of a polymerizable group. The ammonium cations may comprise hydrogen and alkyl substituents (e.g. R⁹, R⁷, R⁶ and R⁸), for example C1-8alkyl substituents, which may be optionally substituted. In some embodiments where the onium cation lacks a polymerizable group, the aromatic carboxylic group comprises a polymerizable group. In another example of Formula 1 above, X is a carboxylate anion group; L^x is an alkenyl divalent linking group, and R¹, R², R⁴ and R⁵ are each hydrogen; and R³ comprises a polymerizable group, such as a methacrylate group optionally linked by an ester or alkyl group.

Another example of a polyionic corrosion inhibitor comprising a non- polymerizable onium cation (i.e. absent of a polymerizable group) and a polymerizable aromatic carboxylate group (i.e. comprising a polymerizable group) is provided below:

In some examples, the polymerizable ionic compound (PIC) may be a polymerizable ionic liquid (PIL).

COATING COMPOSITIONS

A composition may comprise or consist of at least one corrosion inhibitor selected from a polyionic corrosion inhibitor and polymerizable ionic compound (PIC) according to any embodiments or examples thereof as described herein, and optionally one or more additives.

A curable coating composition may further comprise or consist of an organic film former, and optionally one or more additives. The organic film former can comprise or consist of a polymerizable ionic compound (PIC) or a cured reaction product thereof according to any aspects, embodiments or examples thereof as described herein.

The curable coating composition may be a liquid formulation comprising or consisting of an organic film former, and optionally one or more additives. In one example, the curable coating composition comprises or consists of an organic film former, one or more solvents, and optionally one or more additives, and wherein the organic film former comprises or consists of a polymerizable ionic compound (PIC) or a cured reaction product thereof according to any aspects, embodiments or examples thereof as described herein. The organic film former and optional additives may also be provided according any of the embodiments or examples as described below. Organic Film Former

It will be appreciated that the “organic film former” comprises or consists of a polymerizable ionic compound (PIC) or a cured reaction product thereof according to any aspects, embodiments or examples thereof as described herein, and optionally one or more polymeric constituents.

The organic film former may comprise or consist of a polymerizable onium cation group or compound, and a non-polymerizable aromatic carboxylate counter anion group or compound, each being selected according to any embodiments or examples thereof as described herein, and optionally one or more polymeric constituents. The organic film former may comprise or consist of a polymerizable aromatic carboxylate counter anion group or compound, and a non-polymerizable onium cation group or compound, each being selected according to any embodiments or examples thereof as described herein, and optionally one or more polymeric constituents.

The “organic film former” may comprise or further consist of any other polymeric constituents that could be provided in the composition or coating thereof. Any additional polymeric constituents may consist of any polymers (e.g. co-polymers) or polymerizable components, such as reactive monomers (e.g. resins) that can form polymers in the coatings. The polymeric constituents may consist of polymers, co-polymers, resins, monomers and co-monomers. Some examples of polymeric constituents include any one or more of polyolefins, polyurethanes, polyacrylic acids, polyacrylates, polyethers, polyesters, polyketides, polyamides, or any co-polymers thereof.

The organic film former does not itself cover any additive as described below (e.g. inorganic filler, or wetting agent etc.). For example, if any monomers, co-monomers, resins, co-polymers, and polymers, are present in the composition, formulation or coating thereof, then it is understood those prospective constituents are encompassed by the term “organic film former”. In examples where the organic film former “consists of’ one or more specified constituents, then it will be appreciated that the absence of a prospective polymeric constituent being explicitly specified in the organic film former means the absence of that polymeric constituent from the composition, formulation or coating thereof. In other words, when the term “consists of’ is used so only those polymeric constituents specified to consist in the organic film former are present in the composition, formulation or coating thereof.

The organic film former (in wt % of the total composition or coating) may comprise between about 40 and 99, 50 and 95, or 60 and 90. The organic film former (in wt % of the total composition or coating) may comprise at least 30, 35, 40, 45, 50, 60, 65, 70, 75, 80, 85, 90, 95, or 98. The organic film former (in wt % of the total composition or coating) may comprise less than about 99, 98, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, or 35. The organic film former (in wt % of the total composition or coating) may be in a range provided by any two of these upper and/or lower values.

The PIC (in wt % of the total composition or coating) may comprise between about 1 and 50, 5 and 45, or 10 and 30. The PIC (in wt % of the total composition or coating) may comprise at least 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50. The PIC (in wt % of the total composition or coating) may comprise less than about 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5. The PIC (in wt % of the organic film former) may be in a range provided by any two of these upper and/or lower values.

The PIC (in wt % of the organic film former) may comprise between about 1 and 50, 5 and 45, or 10 and 30. The PIC (in wt % of the organic film former) may comprise at least 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50. The PIC (in wt % of the organic film former) may comprise less than about 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5. The PIC (in wt % of the organic film former) may be in a range provided by any two of these upper and/or lower values.

Optional Additives

In some embodiments or examples, the coating or coating composition further comprises or further consists of one or more optional additive(s).

Other than the organic film former, the additive(s) are usually present in an amount of less than about 15% based on the weight of the composition.

The additive(s) are usually present in an amount of less than about 15% based on the weight of the composition or the organic film former. For example, the amount of all additives combined, if present, may be provided in an amount of less than about 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, or 0.05%. The additives may be provided in an amount of greater than about 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%. The amount of all additive(s), if present, may be provided in an amount (based on the total weight of composition) of a range between any two of the above values, for example between about 0.01% and 10%, between about 0.05% and 5 %, between about 0.1% and about 3%, or between about 0.5% and 2%.

Any reference to “substantially free” generally refers to the absence of a compound in the composition other than any trace amounts or impurities that may be present, for example this may be an amount by weight % in the total composition of less than about 1%, 0.1%, 0.01%, 0.001%, or 0.0001%. The compositions as described herein may also include, for example, impurities in an amount by weight % in the total composition of less than about 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.01%, 0.001%, or 0.0001%.

As further described below in relation to the process conditions for application, in at least some examples the present coating compositions are configured to provide a minimum film forming temperature (MFT) for ambient conditions. For example, the MFT of various coating compositions may be provided at about 0 to 40 °C, 5 to 35 °C, 10 to 30 °C, 15 to 25 °C, or about 20 °C.

It will be appreciated that all the additives are optional and may be added to further enhance application of the coating compositions and/or further enhance performance characteristics of the completed coating system (e.g. composition, substrate, or coating). Examples of suitable additives may include any one or more of the following: i. polymerisation initiators; ii. adhesion promoters; iii. solvents; iv. organic cross-linkers; v. inorganic fillers; vi. wetting agents; vii. rheology modifiers; viii. surfactants; ix. dispersants; x. anti-foaming agents; xi. anti-corrosion reagents; xii. stabilizers; xiii. levelling agents; xiv. pigments; and xv. colorants.

Each of the individual additives are described in further detail below, and may be independently provided in the composition according to any examples or embodiments as described herein. As mentioned, the composition may be a formulation, such as a liquid formulation, for which the following examples and embodiments may apply.

The coating composition can be provided as a coating formulation for commercial and industrial application. A coating formulation can be prepared by dissolving or dispersing the coating compositions, in an appropriate solvent and then mixing them together optionally with one or more additives or dissolving the compositions into a suitable solvent under suitable processing conditions. The coating formulation can be prepared from a multi-part composition which can be pre dissolved in suitable solvents, and which can then be pre-mixed together prior to application of the coating composition to the coated substrate. In an alternative embodiment, the coating composition can be formulated into a one-part stable dispersion, which for example would not require premixing before application. For example, the composition as described herein may be a liquid formulation, such as liquid suspension formulation or liquid dispersion formulation.

The coating composition may be applied in different physical forms such as a solution, dispersion, suspension, mixture, aerosol, emulsion, paste or combination thereof, solutions or dispersions or emulsions are preferred.

Polymerisation Initiators

A polymerisation initiator may be used. Herein “initiator” or “polymerisation initiator” refers to a chemical compound that reacts with a monomer to form an intermediate compound which capable of linking successively with a large number of other monomers into a polymeric compound. The terms “initiator” and “polymerisation initiator” may be used interchangeably within the context of this application. Examples of polymerisation initiators include photoinitiators and thermal initiators.

Examples of polymerisation initiators include:

Depending on the techniques used for preparing the polymers, different initiator agents can be used. In some examples the polymerisation initiator may be a photoinitiator. In some examples the polymerisation initiator may be a thermal initiator. In some embodiments a free radical initiator may be used, wherein free radicals are generated by chemical and/or radiation means. Several types of compounds can initiate polymerisation reactions by decomposing to form free radicals. These compounds include: azo-containing compounds, carboxylic peroxyacids and peroxyesters, alkyl hydroperoxides, and dialkyl and diacyl peroxides, among others. Examples of initiators have been described (Reference: W. D. Cook, G. B. Guise, eds. “Polymer Update: Science & Engineering”, Australian Polymer Science Series Volume 2, Polymer Division, Royal Australian Chemical Institute, printed by Adams Printers, Victoria, Australia, 1989, Chapter 2, pp. 19-66). In one embodiment an initiator is selected from a peroxide or an aliphatic azo compound. The polymerisation initiator may be provided in the composition in an amount (based on wt % of composition) of at least about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In an embodiment, the polymerisation initiator is provided in the composition in an amount (based on wt % of composition) of about 0.1 to 10, 0.5 to 6, 1 to 5, or 2 to 4.

Adhesion Promoter

Various adhesion promoters may be used. In one example, there is provided an acid based adhesion promotor, for example siloxanes. Other examples of adhesion promoters include silanes, such as R-(CH2)n-Si-(OH)m. The adhesion promoter may be provided in the composition in an amount (based on wt % of composition) of at least about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In an embodiment, the adhesion promoter is provided in the composition in an amount (based on wt % of composition) of about 0.1 to 10, 0.5 to 6, 1 to 5, or 2 to 4.

Solvent

The PIC and one or more optional additive may be dissolved or otherwise dispersed in a solvent to obtain the coating composition. The solvent may be a single solvent or a mixture of solvents. Useful solvents include water and/or an organic solvent. Organic solvents can be selected from but not limited to solvents containing groups selected from ketones such as methyl propyl ketone and methyl ethyl ketone; alcohols such an ethanol, isopropanol, tert-butyl alcohol, benzyl alcohol and tetrahydrofurfuryl alcohol; ethers such as glycol ethers, for example di(propylene glycol)dimethyl ether; and/or esters.

Organic solvents such as ethylene glycol ethers or propylene glycol ether can be added to assist in reducing the surface tension and improving the wetting and film forming. Examples include Dow glycol ethers including Cellosolve™ family solvents (such as ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether), Carbitol™ family solvents (diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether or diethylene glycol monohexyl ether), Ecosoft™ and Dowanol™ such as propylene glycol propyl ether (PnP), propylene glycol butyl ether (PnB), dipropylene glycol propyl ether (DPnP)dipropylene glycol methyl ether (DPM).

The solvent may be provided in the composition in an amount (based on wt % of composition) of at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98, or 99. In an embodiment, the solvent is provided in the composition in an amount (based on wt % of composition) of about 50 to 99, 80, to 98, 85 to 97, or 90 to 95.

Organic Crosslinker

The coating and composition as described herein may also include an organic crosslinker. The organic crosslinker may be incorporated into the coating composition prior to application on a coated substrate. Suitable crosslinkers are organic compounds or oligomers comprising of at least two groups capable of reacting with the acid functionalities of the organic polymer. Examples of organic crosslinkers include, but are not limited to aziridine, carbodiimide, epoxy, isocyanate and anhydride.

In some embodiments, the coating composition comprises between 1 and 15 wt % crosslinker (based on the weight of the PIC, polymer or organic film former component).

Inorganic Fillers

The coatings and compositions described herein may comprise an optional inorganic filler. The inorganic filler is selected from but not limited to silica, alumina oxide, titania oxide, clays such as Montmorillonite, laponite and layered double hydroxide. The particle size of an inorganic filler varies from micro meter to sub micro meter, and in one embodiment can be from 0.5 to 500 nanometre or from 1 to 100 nm. In one example the particle size is from 1 to 50 nm.

Wetting Agent

Surface finish can be important for the successful application of decorative coatings, and surface wetting agents can provide further advantages to the coatings or coating compositions. Addition of a wetting agent can also be useful in industrial application for improved control of drying time and obtaining a broader operation window.

Accordingly, the coating or coating composition as described herein may further include a wetting agent. The wetting agent may be incorporated into the coating composition prior to application on a coated substrate. Suitable wetting agents include, but are not limited to, ethers including glycol ethers (e.g. propylene glycol methyl ether (Dowanol PM) or propylene glycol propyl ether (Dowanol PnP), diprolylene glycol propyl ether (DPnP), propylene glycol butyl ether (PnB), dipropylene glycol butyl ether (DPnB), propylene glycol phenyl ether (PPh)).

Rheology Modifiers

Rheology modifiers may include hydroxypropyl methyl cellulose (e.g. Methocell 311), modified urea (e.g. Byk 411, 410), cellulose acetate butyrates (e.g. EastmanTM CAB-551-0.01, CAB-381-0.5, CAB-381-20), and polyhydroxycarboxylic acid amides (e.g. Byk 405).

Surfactants

Surfactants may include fatty acid derivatives (e.g. AkzoNobel, Bermadol SPS 2543), quaternary ammonium salts, ionic and non-ionic surfactants.

Dispersants

Dispersants may include non-ionic surfactants based on primary alcohols (e.g. Merpol 4481, DuPont) and alkylphenol-formaldehyde-bisulfide condensates (e.g. Clariants 1494).

Anti-Foaming Agents

Anti-foaming agents may include BKY®-014, BKY®-1640.

Anti-Corrosion Reagents

Examples of additional anti-corrosion agents include metal salts including rare earth metals, such as salts of zinc, molybate, and barium (e.g. phosphates, chromates, molybdates, or metaborate of the rare earth metals). Anti-corrosion reagents may include phosphate esters (e.g. ADD APT, Anticor C6), alkylammonium salt of (2- benzothiazolythio), succinic acid (e.g. BASF, Irgacor 153), triazine dithiols, and thiadiazoles.

Stabilisers

Stabilizers may include various biocides.

Levelling Agents

Levelling agents such as fluorocarbon-modified polymers (e.g. EFKA 3777). Colorants and Pigments

Colorants may be dyes or pigments and include organic and inorganic dyes such as fluorescents (Royale Pigments and Chemicals LLC) (e.g. to enhance visibility of the reactivation treatment and where it has been applied), fluorescein, and phthalocyanines. Pigments may include organic phthalocyanine, quinaridone, diketopyrrolopyrrole (DPP), and diarylide derivatives and inorganic oxide pigments (for example to enhance visibility and where it has been applied). The addition of small amount of colorants (for example pigments and dyes) may change the colours of the coating distinguishing from the original substrate and is an useful tool servicing for quality control purpose.

In some embodiments, the colorant may be a dye. Dyes may be organic, soluble in the surrounding medium, and black or chromatic substances. The optional additives may for example be selected from those as described in the book "Coating Additives" by Johan Bielemann, Wiley-VCH, Weinheim, New York, 1998. The dyes may include organic and inorganic dyes. The dyes may be organic dyes, such as azo dyes (e.g. monoazo such as arylamide yellow PY73, diazo such as diarylide yellows, azo condensation compounds, azo salts such as barium red, azo metal complexes such as nickel azo yellow PG10, benzimidazone). The dyes may be fluorescents (e.g. Royale Pigment and chemicals, to enhance visibility of the reactivation treatment and where it has been applied), fluorescein, phthalocyanines, porphyrins. In some examples, the colorant may be a UV fluorescent dye. The colorants such as fluorescent dyes could for example be used with UV goggles to look for fluorescence after spraying to insure coverage. It will be appreciated that dyes may be organic soluble for improved compatibility or miscibility with the solvents. Peak absorption may be below about 295 nm, for example, which is the natural cut-on for sunlight. Further examples of fluorescent dyes may include acridine dyes, cyanine dyes, fluorine dyes, oxazine dyes, phenanthridine dyes, and rhodamine dyes.

In some examples, the colorant may be a pigment. Pigments may be in powder or flake-form and can provide colorants which, unlike dyes may be insoluble in the surrounding medium (see “Rompp Lexikon Lacke und Druckfarben”, Georg Thieme Verlag Stuttgart / New York 1998, page 451). Pigments are typically composed of solid particles less than about 1 pm in size to enable them to refract light, for example within light wavelengths of between about 0.4 and 0.7 pm. The pigments may be selected from organic and inorganic pigments including color pigments, effect pigments, magnetically shielding, electrically conductive, anticorrosion, fluorescent and phosphorescent pigments. Further examples of suitable pigments may, for example, be as described in German Patent Application DE-A-2006053776 or EP-AO 692 007. Organic pigments may include may include polycyclic pigments(e.g. phthalocyanide such as copper phthalocyanine, anthraquinones such as dibrom anthanthrone, quinacridones such as quinacridone red PV19, dioxazine such as dioxazine violet PV23, perylene, thionindigo such as tetrachloro), nitro pigments, nitroso pigments, quinoline pigments, and azine pigments. The pigments may be inorganic. The inorganic pigments may be selected from carbon black (e.g. black), titanium dioxide (e.g. white), iron oxides (e.g. yellows, reds, browns, blacks), zinc chromates (e.g. yellows), azurites (e.g. blues), chromium oxides (e.g. greens and blues), cadmium sulphoxides (e.g. greens, yellows, reds), lithopones (e.g. whites). Examples of pigments used in aerospace paint compositions may include organic phthalocyanine, quinaridone, diketopyrrolopyrrole (DPP), and diarylide derivatives and inorganic oxide pigments (for example to enhance visibility and where it has been applied).

Example Formulations

In one example, a coating formulation comprises an organic film former in about 85-95 wt %, an adhesion promotor in about 1-5 wt %, and a photoinitiator in about 1- 8%, and wherein the organic film former comprises a PIC according to any embodiments or examples thereof in about 10-30 wt % (of the total formulation).

In another example, the coating composition may comprise an organic film former comprising a PIC, an adhesion promoter and polymerisation initiator: i) an organic film former comprising: a) a PIC:

b) polymeric constituents:

oxibis(propane-l,2-diyl) diacrylate

dipropylen glycols diacrylate

trimethylolpropane triacrylate

cyclic trimethylolpropane formal acrylate ii) acid based adhesion promotor, for example a silane or siloxane; and iii) polymerization initiator, for example

Darocur.

COATING SYSTEM

In some embodiments, a coating layer provided by the compositions as described herein, may form part of a coating system. A coating system may be provided comprising:

(i) an optionally coated metal substrate;

(ii) one or more optional post coating layers; and

(iii) one or more corrosion protection layers located between (i) and (ii) comprising a polymerizable ionic compound (PIC) or a reaction product thereof, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups. It will be appreciated that the corrosion protection layers may comprise or consist of a polymerizable ionic compound (PIC) or a reaction product thereof, or a coating or coating composition thereof, according to any embodiments or examples as described herein.

COATED SUBSTRATE

Suitable substrates include metals and metal alloys (e.g. steel or aluminium), and composites.

A coated metal substrate may be provided comprising a metal substrate coated with one or more coating layers, wherein at least one of the coating layers comprises a polymerizable ionic compound (PIC) or a reaction product thereof, wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups.

It will be appreciated that there may be provided at least one coating layer comprising or consisting of a polymerizable ionic compound (PIC) or a reaction product thereof, or a coating or coating composition thereof, according to any embodiments or examples as described herein.

For example, a coating may be applied to an optionally coated substrate, wherein the coating comprises or consists of:

(b) optionally one or more additives selected from a solvent, a curing agent, an adhesion promoter, an inorganic filler, a wetting agent, and an organic crosslinker.

In one example, there is provided a coated metal substrate comprising a metal substrate coated with one or more coating layers, wherein at least one of the coating layers comprises or consists of an polymerizable ionic compound (PIC) or reaction product thereof according to any embodiments or examples thereof as described herein.

PROCESS FOR PREPARING AND APPLYING COATINGS

A process for preparing a coating system as described herein may comprise: applying a coating composition according to any embodiments or examples thereof as described herein to an optionally coated substrate to form a coating; and optionally applying at least one post coating layer to the coating present on the optionally coated substrate.

In one example, a process for preparing a coating system may comprise: applying the PIC, cured reaction product or coating composition according to any aspects, embodiments or examples as described herein, to an optionally coated substrate; and optionally applying one or more post coating layer to the coating present on the optionally coated substrate.

The coating composition as described herein can be applied onto a coated substrate to form a coating layer by any method known in the coating industry including spray, drip, dip, roller, brush or curtain coating, especially spray.

The dry thickness of the coating depends on the application. In some embodiments, the dry thickness of the coating layer (in microns) is less than about 300, 250, 200, 150, 100, 75, 50, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. The dry thickness may be in a range provided by any two of these values.

The coating layer provides effective adhesion on the coated substrate and between any primer, intermediate or post coating layers if present on the coating. In one example, the coating layer is a primer coating. The coating layer may include additional adhesion promoters, such as those described or exemplified herein.

Any suitable method known to those skilled in the art may be used to assess whether the adhesive linkage between the coating layer and other layers (e.g. coated substrate or post coating layer). Methods may include but are not limited to ASTM and ISO standards.

Properties include corrosion inhibition, and may include any one or more of low toxicity, environmentally friendly, good processability, miscibility with coating systems, high stability, and improved barrier protection from water.

In another embodiment, there is provided a process for protecting a substrate from corrosion by applying a polymerizable ionic compound (PIC), or reaction product thereof, or composition thereof according to any embodiments or examples as described herein, to the substrate. The substrate may be a tank, conduit or pipe. The substrate may be used in various industrial applications such as water treatment, or acidic environments. The composition may be a formulation according to any examples as described herein, such as a liquid or solid formulation. The solid or liquid formulation may be introduced or dosed into the tank, conduit or pipe, for example. In some examples, the polymerizable ionic compound (PIC) may be a polymerizable ionic liquid (PIL).

EXAMPLES

The present disclosure will now be described with reference to the following non- limiting examples and with reference to the accompanying Figures.

1. Materials and Methods

Reagents -Coumaric acid (also referred to as para-hydroxy cinnamic acid), N-methyldiethanolamine, 2-bromoethanol, 2-bromoethane, 2-(dimethylamino)ethyl methacrylate, potassium hydroxide, 4-vinylaniline, Darocur® (Speedcure 73), Amberlist® A-26 (OH form) and 1-vinylimidazole were obtained from Sigma Aldrich. 1-Bromobutane and 1-bromohexane were obtained from Acros. Oxybis(propane-l,2- diyl) diacrylate, dipropylene glycol diacrylate, trimethylpropyl triacrylate, cyclic trimethylolpropane formal acrylate, and acid-based adhesion promotors were obtained from Arkema/Sartomer. Mild Steel 1020, NaCl aqueous solution, MiliQ water, methanol and ethanol were used without further purification.

NMR

NMR spectra were recorded on a Bruker AC-400 spectrometer under the following experimental conditions: spectral width 15 ppm with 32k data points, flip angle 908, relaxation delay of 1 second, digital resolution of 0.24 Hz/pt.

DSC

DSC spectra were recorded on a DSC Q2000 instrument (TA Instruments) under N2 atmosphere. Samples (5 mg) sealed in aluminium pans were heated from 25 °C to 100 °C at the heating rate of 20 K min ¹ then were left at 100 °C for 3 min in order to eliminate the thermal history. Samples were cooled down to -70 °C at the rate of 2 K min^-1 and were left at 70 °C for 3 min. Samples were heated again to 100 °C at the rate of 20 K min^-1.

ATR-FTIR

ATR-FTIR measurements were performed on Bruker Alpha-P equipment. Spectra were recorded from 350 to 4000 cm ¹ at the resolution of 2 cm^-1.

Potentiodynamic Polarization (PP)

A BioLogic VMP3 multi-channel potentiostat and EC Lab VI 0.44 software were used for PP experiments. A three-electrode cell was used with the steel rod as the working electrode, a titanium mesh counter electrode and Ag/AgCl reference electrode. The reference electrode was placed in a Luggin capillary that was positioned close to the working electrode surface. Open Circuit Voltage (OCV) was monitored for 30 min followed by a PP scan at the scan rate of 0.167 mV s^-1, with the scan range of from 150 mV below OCV to 250 mV above OCV. Three PP curves were obtained for each test solution.

Corrosion Current Density (i_corr) and Corrosion Potential (E_corr)

Specific icorr and E_corr values were extracted from the PP curves using Tafel extrapolation. The curves were approximately linear over the range of 10-25 mV on either side of Ecorr, and so the Tafel extrapolations were made over the data in this range. A value for icorr was taken as the point where the linear section of the anodic and cathodic sections of the PP curves intersected the value for E_corr.

From the icorr values, inhibitor efficiencies (IE) were calculated according to Equation 1 below:

Electrochemical impedance spectroscopy (EIS) was carried out over a test period of 24 h in order to characterise the electrochemical properties of AS 1020 mild steel electrodes immersed in the control solution, solution containing the inhibitor compound, or solution containing polymer coatings. BioLogic VMP3 multi-channel potentiostat was used for the EIS tests. OCV was monitored over the frequency range of 100 kHz to 10 mHz with 6 points per decade and a sinusoidal amplitude of lOmV. Impedance responses were monitored after each hour.

Immersion test and SEM

Immersion tests were conducted over 24 h in control solution (0.01 M NaCl) and in control solution containing the inhibitor compound (10 mM) to determine long-term performance of the inhibitor compound. A 1 cm diameter mild steel sample mounted in epoxy resin was polished to P1200 grit, washed with distilled water, and dried with a stream of N2. The sample was then placed in a desiccator for 1 h before being immersed in 60 mL of solution, and the resulting solution was covered to minimize evaporation. After 24 h, the samples were removed from solution, washed with distilled water, and dried with a stream of N2. The corrosion product was then observed with SEM/EDXS using a JEOL JSM-IT300 scanning electron microscope with attached Oxford X-Max 50mm² EDXS detector, at the accelerating voltage of 20 kV.

Droplet test

Droplet tests were carried out in order to observe and compare the inhibition performance of the different anticorrosive coatings. A drop of 1M NaCl was added to a polymer coated 1020 mild steel samples.

Optical microscopy

A Leica MZ 7 optical microscope in combination with LAS V4.0 software was used to observe surfaces after 24 h of immersion.

Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS)

SEM and EDS were used to observe mild steel surfaces after the immersion test. A JSM-IT300 LV SEM instrument with attached Oxford instrument X-Max 50 mm² EDS detector at 15kV was used at the accelerating voltage of 20 kV. EDS spectra collected for 60 s were processed using AZtec software.

2. Synthesis

2.1 Synthesis of Aromatic Carboxylate Counter Anion Compounds

2.1.1 Para-4-ethyloxycinnamic acid

An exemplary synthesis of para-4-ethyloxycinnamic acid, which may also referred to as para-ethoxy coumaric acid, is provided as follows. p-Coumaric acid (100 mmol), KOH (300 mmol), and KI (cat., 20 mol%) was dissolved in a mixture of ethanol/water (75/25) and stirred at reflux temperature for 1 h. Ethyl bromide (100 mmol) was added and the reaction mixture was stirred at reflux temperature for a further 24 h. The precipitate was filtered and washed with deionised water. The collected precipitate was dried under vacuum for 48 h at 50 °C, to yield the title compound.

2.1.2 Para-4-butyloxycinnamic acid

An exemplary synthesis of para-4-butyloxycinnamic acid, which may also be referred to as para-butoxy coumaric acid, is provided as follows. p-Coumaric acid (1 mol), KOH (3 mol) and KI (cat., 20 mol%) was dissolved in a mixture of ethanol/water (75/25) and refluxed for 1 h. Butyl bromide (1 mol) was added and the reaction mixture was refluxed for a further 24 hours. The solvent was removed and the precipitate was acidified with concentrated HC1. The crude product was filtered, washed with water and recrystallized from a mixture of ethanol/water (75/25). The final product was dried under vacuum for 48 h at 50 °C, to yield the title compound as a white powder. 1H NMR (400 MHz, D20) d 7.57, 7.56, 7.55, 7.55, 7.35, 7.31, 7.01, 7.01, 7.00, 6.99, 6.98, 6.40, 6.40, 6.36, 6.36, 4.85, 4.79, 4.73, 4.11, 4.09, 4.07, 1.77, 1.75, 1.74, 1.73, 1.72, 1.70, 1.48, 1.46, 1.45, 1.43, 1.41, 1.39, 0.94, 0.92, 0.92, 0.90.

2.1.3 Para-4-hexyloxycinnamic acid

An exemplary synthesis of para-4-hexyloxycinnamic acid, which may also referred to as para-hexyloxy coumaric acid, is provided as follows. p-Coumaric acid (1 mol), KOH (3 mol) and KI (cat., 20 mol%) was dissolved in a mixture of ethanol/water (75/25) and refluxed for 1 h. Hexyl bromide (1 mol) was added and the reaction mixture was refluxed for a further 24 hours. The solvent was removed and the precipitate was acidified with concentrated HC1. The crude product was filtered, washed with water and recrystallized from a mixture of ethanol/water (75/25). The final product was dried under vacuum for 48 h at 50 °C, to yield the title compound as a white powder. 1H NMR (400 MHz, D20) d 7.57, 7.57, 7.56, 7.55, 7.54, 7.35, 7.31, 7.01, 7.01, 6.99, 6.99, 6.98, 6.40, 6.40, 6.36, 6.36, 4.85, 4.85, 4.79, 4.75, 4.73, 4.10, 4.09, 4.08, 4.08, 4.06, 4.06, 1.78, 1.76, 1.74, 1.73, 1.71, 1.44, 1.42, 1.40, 1.38, 1.32, 1.31, 1.30, 1.29, 1.29, 1.28, 0.87, 0.85, 0.85, 0.84, 0.83.

2.1.4 Para-4-ethyloxymethacrylatecinnamic acid

An exemplary synthesis of para-4-ethyloxymethacrylatecinnamic acid, which may also be referred to as para-ethyl methacrylate coumaric acid, is provided as follows. p-Coumaric acid (1 mol), KOH (3 mol) and a catalytic amount of KI were dissolved in a mixture of ethanol/water (75/25%) and refluxed 1 hour. 2-bromoethyl methacrylate (1 mol) was added and the reaction mixture was refluxed for a further 24 hours. The solvent was removed and the precipitate was acidified with concentrated HC1. The crude product was filtered, washed with water and recrystallized from a mixture of ethanol/water (75/25%). The final product was dried under vacuum and obtained as a white powder.

2.2 Synthesis of Onium Cation Compounds

2.2.1 N-methyl N -ethyl diethanolammonium bromide

N-methyl N-ethyl diethanolammonium bromide was obtained by quatemizing N- methyl diethanolamine using 2-bromoethane as described as follows. N-methyl diethanolamine was treated dropwise with 2-bromoethane at room temperature. After the addition of the 2-bromoethane, the reaction mixture was then stirred for 24 hours at 50 °C. The product was obtained as a solid and purified by dissolving the solid in a minimum amount of methanol and then precipitating the product in a large excess of ethyl acetate. The precipitate was washed three times with ethyl acetate and dried under vacuum at 40 °C. The final product was obtained as a white powder and stored under inert gas until further use. ¹H NMR (400 MHz, D₂0) d 4.08, 4.07, 4.07, 4.06, 4.05, 4.04, 4.03, 3.59,

3.59, 3.57, 3.57, 3.56, 3.55, 3.54, 3.52, 3.16, 1.40, 1.37, 1.35.

2.2.2 2-(Dimethyl ethanol ammonium) ethyl methacrylate bromide

An exemplary synthesis of 2-(dimethyl ethanol ammonium)ethyl methacrylate is provided as follows. The monomer was prepared by the quaternization of 2-(dimethyl amino)ethyl methacrylate with 2-bromoethanol. 2-(Dimethyl amino)ethyl methacrylate in a reaction vessel was treated dropwise with 2-bromoethanol at 50 °C under magnetic stirring. After the addition of 2-bromoethanol, the reaction mixture was stirred for 24 h. The product was obtained as a solid. The crude product was dissolved in a minimum amount of methanol and precipitated in a large excess of ethyl acetate, in order to remove unreacted compounds. The precipitate was washed three times with ethyl acetate and dried under vacuum at 40 °C. The final product was obtained as a white powder and stored under inert gas until further use. ¹H NMR (400 MHz, D2O) d 6.18, 6.17, 6.17, 5.80, 5.80, 5.79, 5.79, 5.78, 4.79, 4.69, 4.68, 4.67, 4.67, 4.66, 4.65, 4.64, 4.12, 4.12, 4.11, 4.09, 4.08, 4.08, 3.90, 3.90, 3.89, 3.88, 3.87, 3.65, 3.64, 3.64, 3.63, 3.62, 3.27, 1.96, 1.96, 1.95.

2.3 Synthesis of Polyionic Compounds

2.3.1 2-(Dimethyl ammonium)ethyl methacrylate para-4-hydroxy-cinnamate

An exemplary synthesis of 2-(dimethyl ammonium)ethyl methacrylate para-4- hydroxy-cinnamate, which may also be referred to as 2-(dimethyl ammonium)ethyl methacrylate p-coumarate, is provided as follows. 2-(Dimethyl amino)ethyl methacrylate and p-coumaric acid were weighed and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. ¹H NMR (300 MHz, DMSO) d 7.53, 7.52, 7.51,

7.50, 7.49, 7.48, 7.46, 6.82, 6.81, 6.80, 6.78, 6.78, 6.77, 6.31, 6.26, 6.03, 6.03, 6.02, 6.02, 6.02, 6.02, 5.69, 5.68, 5.68, 5.67, 5.67, 4.32, 4.20, 4.18, 4.17, 4.16, 3.18, 2.56, 2.54, 2.52,

2.51, 2.51, 2.50, 2.50, 2.30, 2.19, 2.09, 1.88, 1.88, 1.88, 1.88. 2.3.2 2-(Dimethyl ethanol ammonium)ethyl methacrylate para-4-hydroxy-cinnamate

An exemplary synthesis of 2-(dimethyl ethanol ammonium)ethyl methacrylate para-4-hydroxy-cinnamate, which may also be referred to as 2-(dimethyl ethanol amino)ethyl methacrylate trans-4-hydroxy-cinnamate, is provided as follows. Anion exchange resin Amberlist A-26 (OH form) was used in order to effect bromide exchange for the p-coumarate anion in 2-(dimethyl ethanol ammonium)ethyl methacrylate bromide. A column was filled with the aforementioned resin. p-Coumaric acid (aqueous solution, 0.01M) was passed through the column. The acid-based reaction with hydroxides occurred, resulting in the retention of the p-coumarate anion on the resin. 2- (Dimethyl ethanol amino)ethyl methacrylate bromide solution was passed through the column containing A-26 (R-p-coumarate form), and 2-(dimethyl ethanol ammonium)ethyl methacrylate p-coumarate was obtained after evaporation of methanol. The product was obtained as a viscous liquid. ¹H NMR (400 MHz, DMSO) d 7.28, 7.28,

7.27, 7.26, 7.09, 7.05, 6.78, 6.77, 6.76, 6.76, 6.19, 6.15, 6.10, 6.09, 6.09, 5.76, 5.75, 5.75,

5.74, 4.56, 4.55, 4.55, 4.54, 4.54, 3.91, 3.89, 3.88, 3.86, 3.84, 3.84, 3.83, 3.82, 3.82, 3.69,

3.65, 3.56, 3.56, 3.55, 3.55, 3.54, 3.53, 3.52, 3.51, 3.50, 3.22, 3.19, 3.18, 3.16, 2.52, 2.52,

2.52, 2.51, 2.51, 1.91, 1.91, 1.90, 1.24.

2.3.3 2-(Dimethyl ammonium)ethyl methacrylate para-4-butoxycinnamate

An exemplary synthesis of 2-(dimethyl ammonium)ethyl methacrylate trans-4- butoxycinnamate, which may also be referred to as 2-(dimethyl amino)ethyl methacrylate para-butoxy cinnamate, is provided as follows. 2-(Dimethyl amino)ethyl methacrylate and 4-butoxycinnamic acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1H NMR (400 MHz, D20) d 7.55, 7.53, 7.34, 7.30, 6.99, 6.97, 6.38, 6.34, 5.62, 5.30, 4.79, 4.09, 4.07, 4.05, 3.75, 3.74, 3.72, 2.79, 2.77, 2.76, 2.45, 2.27, 1.84, 1.76, 1.74, 1.72, 1.71, 1.69, 1.45, 1.44, 1.42, 1.40, 0.93, 0.92, 0.90.

2.3.4 2-(Dimethyl ammonium)ethyl methacrylate para-4 -hexyloxy cinnamate

An exemplary synthesis of 2-(dimethyl ammonium)ethyl methacrylate para-4- hexyloxycinnamate is provided as follows. 2-(Dimethyl amino)ethyl methacrylate and 4-hexyloxy cinnamic acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1H NMR (400 MHz, D20) d 7.84, 7.55, 7.53, 7.41, 7.34, 7.30, 7.08, 7.06, 7.04, 7.02, 6.99, 6.97, 6.39, 6.35, 5.44, 5.40, 4.99, 4.98, 4.96, 4.79, 4.08, 4.06, 4.05, 1.77, 1.75, 1.73, 1.71, 1.70, 1.43, 1.41, 1.39, 1.31, 1.30, 1.28, 0.86, 0.85, 0.83.

2.3.5 1 - Vinylimidazole para-4-hexyloxycinnamate

An exemplary synthesis of 1 -vinylimidazole p-hexyloxy cinnamate is provided as follows. 1 -Vinylimidazole and 4-hexyloxy cinnamic acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1H NMR (400 MHz, D20) d 7.84, 7.55, 7.53, 7.41, 7.34, 7.30, 7.08, 7.06, 7.04, 7.02, 6.99, 6.97, 6.39, 6.35, 5.44, 5.40, 4.99, 4.98, 4.96, 4.79, 4.08, 4.06, 4.05, 1.77, 1.75, 1.73, 1.71, 1.70, 1.43, 1.41, 1.39, 1.31, 1.30, 1.28, 0.86, 0.85, 0.83. 2.3.6 4-Vinylaniline para-4-hexyloxycinnamate

An exemplary synthesis of 4-vinylaniline para-hexyloxy cinnamate is provided as follows. 4-Vinylaniline and 4-hexyloxycinnamic acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1H NMR (400 MHz, D20) d 7.57, 7.55, 7.35, 7.34, 7.31, 7.01, 6.99, 6.81, 6.79, 6.71, 6.64, 6.40, 6.36, 5.66, 5.62, 5.11, 5.09, 4.10, 4.08, 4.07, 1.78, 1.76, 1.75, 1.73, 1.71, 1.44, 1.42, 1.40, 1.32, 1.31, 1.30, 1.29, 1.29, 0.87, 0.85, 0.83.

2.3.7 4-Vinylpyridine para-hexyloxy cinnamate

An exemplary synthesis of 4-vinylpyridine para-hexyloxy cinnamate is provided as follows. 2-Vinylpyridine and p-hexoxy coumaric acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1H NMR (400 MHz, D20) d 8.22, 8.21, 7.26, 7.24, 7.19, 7.15, 7.13, 6.59, 6.56, 6.50, 6.47, 6.45, 6.42, 6.20, 6.16, 5.84, 5.80, 5.32, 5.30, 4.71, 3.62, 3.60, 3.59, 1.46, 1.44, 1.42, 1.17, 1.15, 1.13, 1.11, 1.08, 1.08, 0.71, 0.70, 0.68.

2.3.8 Tetrabutylammonium para-ethyloxy methacrylate triethylammonium salt

An exemplary synthesis of tetrabutylammonium para-ethyl methacrylate coumarate is provided as follows. Triethylamine and para-ethyloxy methacrylate coumaric acid were weighted and mixed in an equimolar amount. The product was obtained instantly as a viscous liquid. 1HNMR(400 MHz, D20) d 7.57, 7.55, 7.51, 7.49, 7.35, 7.31, 7.02, 7.00, 6.39, 6.35, 4.79, 4.16, 4.15, 4.14, 3.91, 3.90, 3.89, 2.70, 2.68, 2.66, 2.64, 1.88, 1.06, 1.04, 1.02.

3. Preparation of Polymer Coatings

3.1 Preparation of polymer coating containing 2- ( dimethyl amino )ethyl methacrylate p-coumarate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur® (Speedcure 73) (5% w/w) and 2-(dimethyl amino)ethyl methacrylate p-coumarate (20% w/w) were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and then UV cured.

3.2 Preparation of polymer coating containing 2-(dimethyl amino)ethyl methacrylate p-butyloxy coumarate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur (Speedcure 73) (5% w/w) and 2-(dimethyl amino)ethyl methacrylate p-butyloxy coumarate (20% w/w), were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and it was UV cured. 3.3 Preparation of polymer coating containing 2-(dimethyl amino)ethyl methacrylate p-hexyloxy coumarate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur (Speedcure 73) (5% w/w) and 2-(dimethyl amino)ethyl methacrylate p-hexyloxy coumarate (20% w/w) were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and it was UV cured.

3.4 Preparation of polymer coating containing 1 -vinylimidazole para-4- hexyloxycinnamate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur (Speedcure 73) (5% w/w) and 1 -vinylimidazole para-4-hexyloxycinnamate (20% w/w) were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and it was UV cured.

3.5 Preparation of polymer coating containing 4-vinylaniline para-4- hexyloxycinnamate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur (Speedcure 73) (5% w/w) and 4-vinylaniline para-4-hexyloxycinnamate (20% w/w) were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and it was UV cured. 3.6 Preparation of polymer coating containing 4-vinylpyridine para-hexyloxy cinnamate

Oxybis(propane-l,2-diyl) diacrylate (40% w/w), dipropylene glycol diacrylate (25% w/w), trimetyl propyl triacrylate (13% w/w), cyclic trimethylolpropane formal acrylate (12% w/w), acid based adhesion promotor (3% w/w), Darocur (Speedcure 73) (5% w/w) and 4-vinylpyridine para-hexyloxy cinnamate (20% w/w) were added and mixed in a vial. A mild Steel 1020 surface was prepared in order to have a rectangular gap to a depth of 62.5 pm. The gap was filled with the aforementioned mixture and it was UV cured.

4. Corrosion Inhibitor Testing of Polymer Coated Metals

Various examples of polymerizable ionic compounds were prepared and tested as cured coatings and for corrosion inhibition properties. Figures 1-5 provides examples where the polymerizable group is on the onium nitrogen cation, and Figure 6 provides examples where the polymerizable group is on the aromatic carboxylate group.

Coatings were prepared on mild steel containing 20 weight % of a polymerizable ionic compound (see Figure 1A, Figure IB and above Examples 2.3.1 and 2.3.4 to 2.3.7). Figure 2 is an Electrochemical Impedance Spectra (EIS) for the coated steel specimens immersed in 1M NaCl solution for 24 hours; black - control coating without any polymerizable ionic compounds; red - coating with 20 weight % [p-OHcoum]MA polymerizable ionic compound (see above Example 2.3.1); blue- coating with 20 weight % [p-O(C₆H₁₃)coum]MA polymerizable ionic compound (see above Example 2.3.4). Larger impedance signifies greater corrosion inhibition and better barrier properties. Figures 3A-C show a time evolution of EIS bode plots for control coating and coatings containing 20 weight % [pOHcoum]MA (see above Example 2.3.1) and [pOC₆H₁₃]MA (see above Example 2.3.4) polymerizable ionic compounds according to two examples of the present disclosure immersed in NaCl aqueous solution. The highest impedance shown is the coating containing [pOC₆H₁₃]MA (see above Example 2.3.4) polymerizable ionic compound. Figure 4 shows polymer coatings on AS 1020 mild steel containing 20% of [p-OHcoum]MA, 20% of [p-O(C₄H₉)coum]MA, and 20% of [ p-O(C₆H₁₃)coum] MA after an immersion of 20h in 0.005 M NaCl. It was observed that [p-OHcoum]MA take water during immersion. On the other hand, increasing the length of the alkyl chain attached to the oxygen of the coumarate anion, the hydrophobicity is increased and so the weight of [p-O(C₄H₉)coum]MA and [p-O(C₆H₁₃)coum]MA remained constant. It is concluded that for coatings containing 20% [p-O(C₄H₉)coum]MA and 20% [p- 0(C₆H₁₃)coum]MA, water swelling may not happen, due to the hydrophobicity provided by the attached alkyl chains. In that way, a greater barrier capacity can be observed in coatings containing 20% [p-O(C₄H₉)coum]MA and 20% [p-O(C₆H₁₃)coum]MA inhibitors.

Various polymerizable ionic compounds were prepared where an onium nitrogen cation contained a polymerizable group (see Figures 5A-D and above Examples 2.3.1, 2.3.3, 2.3.4, 2.3.5, 2.3.6, and 2.3.7). The polymerizable ionic compounds were tested as UV cured coatings at a level of 20 weight % of the PIC in the total weight of the coating. In each case the anion is the same but the polymerizable group on the nitrogen cation is modified. A significant impact on improved corrosion performance was shown. Figure 5B(i) shows EIS bode impedance plots for UV cured coatings containing 20 weight % of the different polymerizable ionic compounds (PIC) compared with the control coating. The PIC of [p-O[C₆H₁₃)coum]AN (see above Example 2.3.6) provides very high impedances after 24 hours. The PIC of [p-O[C₆H₁₃)coum]IM (see above Example 2.3.5) also shows particularly high impedance values. Figure 5C shows Nyquist plots after 24 hours immersion of the coatings in NaCl aqueous solution. Same data is provided as the Bode plots in Figure 5B(i) above but in different format. The PIC of [p- 0[C₆H₁₃)coum]IM (see above Example 2.3.5) shows highest impedance values and these test demonstrate the significance of the coating barrier and corrosion protection properties on the PIC chemistry. Pictures of all coatings were taken after EIS measurements (Figure 5B(ii)). The control coating presents some rust deposits on the surface. In contrast, [p-O[C₆H₁₃)coum]MA, [p-O[C₆H₁₃)coum]IM and [p- 0[C₆H₁₃)coum]AN based polymer coatings do not suffer any deterioration. The scribe test was carried out in order to further compare the different coatings. A defect was introduced into a reference UV polymer coating without any inhibitor, and coatings containing 20wt% [p-O[C₆H₁₃)coum]MA, [p-O[C₆H₁₃)coum]IM, [p-O[C₆H₁₃)coum]AN and [p-O[C₆H₁₃)coum]PY, respectively. The coatings were introduced into acidic solutions in order to initiate the corrosion reaction. In Figure 5D, filiform corrosion pictures of all coatings can be observed after 10 days. As can be observed, the control coating without inhibitors shows a completely rust covered surface. On the other hand, the polymer coatings containing inhibitors passed the scribe test very well showing little to no corrosion propagation. All systems are significantly improved over the control (without any PIC).

Various polymerizable ionic compounds were prepared where the aromatic carboxylate anion contained a polymerizable group. Figures 6A & 6B provides a schematic of the preparation (Figure 6A) and EIS bode impedance plots (Figure 6B) for UV cured coatings containing 20 weight % of the anionic polymerizable ionic compound [p-O(MEM)coum] according to one example of the present disclosure (see above Example 2.3.8) compared with the control coating. Four orders of magnitude higher impedance is observed.

5. Mild Steel Corrosion Inhibition Properties of p-hexoxy coumarate based monomeric ionic liquids

In order to investigate the effect of the cation on the corrosion inhibition properties of the coumarate ionic liquids, four different cationic monomers having ammonium, imidazolium, pyridinium and anilinium cations, were tested. The protic ionic liquid monomers were obtained by acid-base proton exchange reaction between the cationic monomers and p- hexoxy coumaric acid. The chemical structure of the four monomers investigated in this work is shown in Figure 7, [p-O[C₆H₁₃)coum]MA, [p- 0[C₆H₁₃)coum]IM, [p-O[C₆H₁₃)coum]AN and [p-O[C₆H₁₃)coum]PY.

The corrosion inhibition properties of the monomers were evaluated by immersing mild steel AS 1020 foils into an aqueous solution of the ionic monomers. By this method it is expected that the organic ionic compounds may adsorb onto the mild steel surface forming a corrosion inhibition layer as illustrated in the Figure 7.

Potentiodynamic polarisation scans of AS 1020 mild steel after an exposure of 24h in O.OlMNaCl control solution and inhibitors containing solutions (O.OlMNaCl + 8mM inhibitor monomers) are shown in Figure 8A. Corrosion potentials (E_corr), corrosion current density (icon), tafel anodic and cathodic slopes (β₃ and β_e) calculated using Tafel extrapolation are displayed in Figure 8B. It can be observed that for all the inhibitors the corrosion potential (E_corr) is shifted towards a more positive value compared with the control, meaning that all the inhibitors are mainly affecting and suppressing the anodic reaction of the corrosion. However, differences in both the anodic and cathodic Tafel slopes can be observed, suggesting that, apart from blocking the anodic reaction, the cathodic reaction is also affected by the presence of these compounds. In most cases the corrosion current decreased considerably compared with the control, yielding very high inhibitor efficiency values. Electrochemical Impedance Spectroscopy experiments were carried out in order to further characterize the anticorrosive capacity of different inhibitors. The impedance responses were measured during an immersion in NaCl 0.01M aqueous solution for 24 h. Figure 9 shows the Nyquist plot at the beginning of the test and after 24 h of immersion in NaCl 0.01 M aqueous solution. This data is fully consistent with the PP data in Figure 8A and 8B, and suggests a co-dependence of the anion and cation on the adsorption on steel from aqueous solution and hence a significant effect on the corrosion performance.

The Bode plots of the control and the comparison with the different inhibitors as a function of immersion time are shown in the Figure 10. Figure 10 also shows optical images of the mild steel samples immersed in control, [p-O[C₆H₁₃)coum]MA, [p- 0[C₆H₁₃)coum]IM, [p-O[C₆H₁₃)coum]AN and [p-O[C₆H₁₃)coum]PY. The control sample presents a surface covered red rust, while the inhibitor immersed samples are not showing evidence of such corroded areas.

In order to corroborate the corrosion inhibition effect, the mild steel samples were evaluated using electron microscopy of the surfaces. Mild steel AS 1020 surfaces were analyzed after an immersion of 24 h in 0.01 M NaCl with and without monomeric ionic liquid inhibitors by optical microscopy, scanning electron microscopy and electron diffraction spectroscopy. In Figure 11, rust deposits can be observed on the surface immersed in the control solution (optical and scanning electron microscopy images). As it can be seen in the optical images of all samples, the surfaces in contact with solutions containing inhibitors do not present rust deposits. EDS analysis confirmed the presence of carbon, oxygen and nitrogen atoms on these surfaces, indicating the creation of an organic inhibiting layer onto the metallic surface. The surfaces exposed to [p- O[C₆H₁₃)coum]MA and [p-O[C₆H₁₃)coum]IM, show the least corrosive attack, consistent with the electrochemistry data. Thus, it can be concluded that although the p- hexoxy coumarate anion is expected to be the predominant anticorrosive moiety in cationic monomers, the cationic part also has an important effect. This suggests that the speciation in solution may be different and this affects the adsorption behaviour of the ions.

Claims

CLAIMS:

1. A method for inhibiting corrosion on a substrate by providing one or more coatings on the substrate, wherein at least one coating comprises a polymerizable ionic compound (PIC) or a cured reaction product thereof, and wherein the PIC comprises onium cation groups and aromatic carboxylate counter-anion groups.

2. The method of claim 1, wherein the cured reaction product comprises a polymer chain containing a plurality of the onium cation groups covalently linked as individual pendant groups along the polymer chain, and wherein the aromatic carboxylate counter anion groups provide counter-ions for the onium cation groups.

3. The method of claim 1, wherein the cured reaction product comprises a polymer chain containing a plurality of the aromatic carboxylate counter-anion groups covalently linked as individual pendant groups along the polymer chain, and wherein the onium cation groups provide counter-ions for the aromatic carboxylate counter-anion groups.

4. The method of any one of claims 1 to 3, wherein the aromatic carboxylate counter anion groups are of Formula 1:

Formula 1 wherein

X is an optionally linked carboxylate anion group; and

R¹, R² R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)- heteroalkenyl, and a polymerizable group.

5 The method of claim 4, wherein:

X is an optionally linked carboxylate anion group; _{R1 and R5 are hydrogen; and} _{R2, R3, and R4, are each independently selected from hydrogen, alkyl, alkenyl,} _{heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, and a} _{polymerizable group.}

_{6. The method of claim 4 or claim 5, wherein at least one of R2, R3, and R4, is} _{selected from O-alkyl, O-alkenyl, O-heteroalkyl, and O-heteroalkenyl.}

_{7. The method of any one of claims 4 to 6, wherein at least one of R2, R3, and R4, is} _{selected from O-C1-12alkyl, O-C2-12alkyl, or O-C3-6alkyl.}

_{8. The method of any one of claims 4 to 7, wherein each of R1, R2, R4, and R5, are} _{hydrogen, and R3 is selected from O-C1-12alkyl, O-C2-12alkyl, or O-C3-6alkyl.}

_{9. The method of any one of claims 1 to 8, wherein the onium cation groups are} _{polymerizable quaternary onium cation groups selected from ammonium cation groups,} _{pyridinium cation groups, imidazolium cation groups, pyrazolium cation groups, and} _{pyrrolidinium cation groups.}

_{10. The method of any one of claims 1 to 9, wherein the onium cation groups are} _{polymerizable nitrogen cation groups of Formula 2a(i):}

_{Formula 2a(i)} _wherein _{A is a polymerizable group;} _{R6, R7, and R8, are each independently selected from hydrogen, alkyl, alkenyl,} _{heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and heteroarylalkyl, or two or more} _{of R6, R7, and R8 together provide an aromatic or aliphatic ring.}

_{1 1. The method of any one of claims 1 to 10, wherein the onium cation groups are} _{polymerizable ammonium cation groups of Formula 2a(ii):}

Formula 2a(ii) wherein

R^6a, R^7a, and R^8a, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, and heteroaryl are optionally substituted with one or more hydroxyl groups;

R^9a is hydrogen or methyl; and n is an integer of 1 to 6.

12. The method of any one of claims 1 to 11, wherein the onium cation groups in the cured reaction product are ammonium cation groups of Formula 3:

Formula 3 wherein wavy line indicates a portion of the polymer chain;

L² is a divalent linking group to the polymer chain selected from alkyl, alkenyl, heteroalkyl, and heteroalkenyl; and

R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, and heteroaryl are optionally substituted with one or more hydroxyl groups.

13. The method of any one of claims 1 to 12, wherein the coating or polymer chain of the cured reaction product comprises a polyolefin, polyurethane, polyacrylate, polyether, polyester, polyketide, polyamide, or any co-polymers thereof.

14. The method of any one of claims 1 to 13, wherein the coating or polymer chain of the cured reaction product comprises a polyacrylate, polyurethane, or any co-polymers thereof.

15. The method of any one of claims 1 to 14, wherein the PIC or the cured reaction product is provided in the coating in an amount between about 5 and 40 wt % of the total amount of polymeric constituent in the coating.

16. The method of any one of claims 1 to 15, wherein the PIC, cured reaction product, or coating, comprises one or more additives selected from a solvent, a curing agent, an adhesion promoter, an inorganic filler, a wetting agent, and an organic crosslinker.

17. The method of any one of claims 1 to 16, wherein the substrate is a metal substrate.

18. The method of any one of claims 1 to 17, wherein the coating comprises a cured reaction product of a polymerizable ionic compound (PIC) comprising an aromatic carboxylate compound of Formula 1 and a polymerizable ammonium compound of Formula 2a(i):

Formula 1 Formula 2a(i) wherein

X is an optionally linked carboxylate anion group;

R¹ to R⁵ are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O-heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)-heteroalkenyl, and a polymerizable group;

A is a polymerizable group; R⁶, R⁷, and R⁸, are each independently selected from hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, heteroaryl, and wherein the alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, arylalkyl, and heteroaryl are optionally substituted with one or more hydroxyl groups.

19. The method of any one of claims 1 to 18, wherein the polymerizable group is selected from an epoxy, acrylamide, acrylate, and vinyl group.

20. The method of any one of claims 1 to 19, wherein the polymerizable group is an ethylenically unsaturated terminal group selected from a vinyl, (meth)acryl and acrylate group.

21. A coated metal substrate comprising a metal substrate coated with one or more coating layers, wherein at least one of the coating layers comprises a polymerizable ionic compound (PIC) or a reaction product thereof as defined in any one of claims 1 to 20 or 23 to 28.

22. A coating system comprising:

(i) an optionally coated metal substrate;

(ii) one or more optional post coating layers; and

(iii) one or more corrosion protection layers located between (i) and (ii) comprising a polymerizable ionic compound (PIC) or a reaction product thereof as defined in any one of claims 1 to 20 or 23 to 28.

23. A polymerizable ionic compound comprising or consisting of an optionally polymerizable aromatic carboxylate of Formula 1 and an optionally polymerizable onium cation, or any salts, conjugates or reaction products thereof:

Formula 1 wherein X is an optionally linked carboxylate anion group; and

24. The polymerizable ionic compound of claim 23, wherein the aromatic carboxylate counter-anions are of Formula 1 and the onium cations are of Formula 2a(i):

Formula 1 Formula 2a(i) wherein

Z is an optionally linked carboxylate anion group;

R¹ and R⁵ are hydrogen;

R², R³, and R⁴ are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O- heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, O-C(=O)- heteroalkenyl;

A is a polymerizable group;

25. The polymerizable ionic compound of claim 24, wherein the aromatic carboxylate counter-anions are of Formula la:

wherein

Z is a carboxylate group;

R¹ and R⁵ are hydrogen;

R² R³, and R⁴ are each independently selected from hydrogen, halo, hydroxyl, alkyl, alkenyl, heteroalkyl, heteroalkenyl, O-alkyl, O-alkenyl, O-heteroalkyl, O- heteroalkenyl, O-C(=O)-alkyl, O-C(=O)-alkenyl, O-C(=O)-heteroalkyl, and O-C(=O)- heteroalkenyl.

26. The polymerizable ionic compound of claim 25, wherein at least one of R², R³, and R⁴, is selected from O-alkyl, O-alkenyl, O-heteroalkyl, and O-heteroalkenyl.

27. The polymerizable ionic compound of claim 25, wherein at least one of R², R³, and R⁴, is selected from O- C_1-12alkyl, O-C2-12alkyl, or O-C3-₆alkyl.

28. The polymerizable ionic compound of claim 25, wherein each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is selected from O-C_1-12alkyl, O-C2-12alkyl, or O-C3-₆alkyl.

29. A curable coating composition comprising or consisting of an organic film former, wherein the organic film former comprises or consists of a polymerizable ionic compound (PIC) or a cured reaction product thereof as defined in any one of claims 23 to 28.

30. The coating composition of claim 29, wherein the composition is a liquid formulation comprising one or more liquid carriers.

31. The coating composition of claims 29 or claim 30, wherein the composition further comprises at least one film former selected from a polymerizable monomer, oligomer, and polymer.

32. The coating composition of any one of claims 29 to 31, wherein the composition comprises one or more additives selected from a solvent, a curing agent, an adhesion promoter, an inorganic filler, a wetting agent, and an organic crosslinker.

33. A process for preparing a coating system comprising: applying the polymerizable ionic compound (PIC) or coating composition according to any one of claims 23 to 32 to an optionally coated substrate; and optionally applying one or more post coating layer to the coating present on the optionally coated substrate.

34. A compound of Formula 1a or salt thereof:

Formula 1a wherein

X is a carboxylic acid or carboxylate group;

R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, C_1-12alkyl, C_1-12alkenyl, C_1-12heteroalkyl, C_1-12heteroalkenyl, O- C_1-12alkyl, O- C_1-12alkenyl, O-C_1-12heteroalkyl, O-C_1-12heteroalkenyl, and a polymerizable group; with the proviso that R³ is not hydrogen, hydroxyl or methoxyl, when R¹, R², R⁴, and R⁵, are hydrogen and L¹-Z is -CH=CH-C(=O)OH.

35. The compound of claim 34, wherein the compound of Formula la is a compound of Formula 1a(i) or salt thereof:

Formula 1a(i) wherein Y is a cation;

R¹, R², R³, R⁴, and R⁵, are each independently selected from hydrogen, halo, hydroxyl, C_1-12alkyl, C_1-12alkenyl, C_1-12heteroalkyl, C_1-12heteroalkenyl, C_1-12alkyl, O- C_1-12alkenyl, O-C_1-12heteroalkyl, O-C_1-12heteroalkenyl, and a polymerizable group.

36. The compound of claim 34 or claim 35, wherein at least one of R², R³, and R⁴, is selected from O-alkyl, O-alkenyl, O-heteroalkyl, and O-heteroalkenyl.

37. The compound of any one of claims 34 to 36, wherein at least one of R², R³, and R⁴, is selected from O- C_1-12alkyl, O-C_2-12alkyl, or O-C_3-6alkyl.

38. The compound of any one of claims 34 to 38, wherein each of R¹, R², R⁴, and R⁵, are hydrogen, and R³ is selected from O-C_1-12alkyl, O-C_2-12alkyl, or O-C_3-6alkyl.

39. The compound of any one of claims 34 to 38, wherein Y is selected from any onium cation as defined in any one of claims 9 to 13.