JP2017154036A - Silicone member for fluid device, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone member for a fluid device having a fine flow pass where at least only a part of a concavity has hydrophilicity, and an easy method of manufacturing the same.SOLUTION: A silicone member 20 for a fluid device is an integrated body made of silicone, and one plane contacting fluid is composed of a concavity 21 for capturing the fluid, and a flow pass part 22 other than thereof. In a fluid device 1, at least one part of the concavity 21 is hydrophilic, and the concavity 21 other than the part and the flow pass part 22 are hydrophobic. The method of manufacturing the silicone member 20 for a fluid device includes: a hydrophilicity process of treating one plane of a base material made of silicone having a concavity on the one plane by at least one method of a CVD method and a plasma irradiation method to form a hydrophilic layer 210 on one whole plane; and a hydrophobicity process of forming a hydrophobic layer 220 on a surface of the hydrophilic layer 210 other than the concavity of the one plane.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a silicone member useful for a fluid device having a fine flow path and a method for producing the same.

  When a microfluidic device in which a fine flow path is formed in a substrate, various operations such as reaction, extraction, separation, and measurement can be performed in a short time with a very small amount of sample. As a material for the substrate, glass is generally used. However, processes such as photolithography and dry etching are required to form a fine channel on a glass substrate. For this reason, it takes time to manufacture the substrate and the productivity is low. Moreover, when a board | substrate is glass, there also exists a problem that the disposal by incineration cannot be performed. Therefore, silicone is attracting attention as a material that can replace glass, because it is easy to process finely and has excellent light transmission and chemical resistance.

JP 2006-181407 A International Publication No. 2008/065868 JP2013-202000A

  Compared to a glass substrate, a silicone substrate has a lower affinity for water. For this reason, when a hydrophilic solution is caused to flow through the flow path, there is a possibility that a desired operation cannot be performed accurately due to poor flowability. In addition, there is a problem that a component to be trapped is difficult to enter into the recess formed on the substrate. Therefore, when a silicone substrate is used, a treatment for imparting hydrophilicity to the surface is performed (see, for example, Patent Documents 1 and 2).

  However, in the conventional method, the entire substrate surface including the recesses is hydrophilized. In this case, the flowability is improved, but the component to be captured easily adheres to other than the recesses. For this reason, there is a possibility that the loss of the sample is large and the analysis accuracy is lowered.

  For example, Patent Document 3 describes a microchemical device in which an upper plate having a through hole and a flat plate-like lower plate are stacked and joined in the vertical direction. In the device of Patent Document 3, a recess is formed by the through hole of the upper plate and the surface of the lower plate. Then, the surface state of the bottom surface and the side surface of the recess is made different by using silicone as the material of the upper plate and resin other than silicone as the material of the lower plate. However, in order to manufacture the device described in Patent Document 3, it is necessary to manufacture two types of plates, and further, a step of joining them is necessary. For joining, alignment and various treatments are required. For this reason, a manufacturing process is complicated and cost becomes high.

  This invention is made | formed in view of such an actual condition, and makes it a subject to provide the silicone member for fluid devices in which only at least one part of a recessed part has hydrophilic property, and its easy manufacturing method.

  (1) In order to solve the above-mentioned problem, the silicone member for a fluid device of the present invention (hereinafter sometimes simply referred to as “the silicone member of the present invention”) is an integral one made of silicone, and is in contact with the fluid. Consists of a recess for capturing a part of the fluid and a channel part other than that, and at least a part of the recess is hydrophilic, and the recess and the channel part other than the part are It is characterized by being hydrophobic.

  The silicone member of the present invention is an integral body made of silicone. That is, a plurality of members are not formed by being laminated or bonded, but are integrally formed from silicone. For this reason, manufacture is easy compared with the case where a several member is combined. In addition, various recess patterns having different sizes and shapes can be easily formed according to the purpose.

  The silicone member of the present invention has one surface that comes into contact with a fluid, and the one surface includes a recess for capturing a part of the fluid and a channel portion other than the recess. Here, at least a part of the recess is hydrophilic, and the other surface (the recess and the channel part other than the part) is hydrophobic. When all of the recesses are hydrophilic, only the flow path part becomes hydrophobic. Therefore, it is possible to reliably capture the component to be captured without adhering to any part other than the recess. Thereby, the loss of a sample can be reduced and analysis accuracy can be improved. In this specification, the case where the water contact angle measured according to JIS R3257: 1999 is less than 80 ° is defined as hydrophilic, and the case where the water contact angle is 80 ° or more is defined as hydrophobic.

  (2) As an example of the method for producing a silicone member of the present invention, the method for producing a silicone member for a fluid device of the present invention (hereinafter sometimes simply referred to as “the production method of the present invention”) has a recess on one side. With respect to the silicone base material, the one surface is treated by at least one of a plasma CVD method and plasma irradiation to form a hydrophilic layer on the entire surface, and the one surface of the one surface other than the concave portion. And a hydrophobizing step of forming a hydrophobic layer on the surface of the hydrophilic layer.

  In the hydrophilization step, one surface is modified by plasma CVD (chemical vapor deposition) method and / or plasma irradiation to modify one surface, or a thin film is formed on one surface, or both. A hydrophilic layer can be formed on one surface. Thereafter, in the hydrophobizing step, by forming a hydrophobic layer on the surface of the hydrophilic layer other than the concave portion, the surface other than the concave portion, that is, the flow path portion can be made hydrophobic. Thus, according to the manufacturing method of this invention, the silicone member of this invention of the form which only a recessed part has hydrophilic property can be manufactured easily and for a short time.

It is a permeation | transmission top view of a fluid device provided with the silicone member of this invention. It is II-II sectional drawing of the fluid device. It is III-III sectional drawing of the fluid device. It is the schematic of the hydrophilization process in manufacture of the lower side member of the fluid device. It is the schematic of the hydrophobization process in manufacture of the lower side member of the fluid device. It is the schematic of the lamination process in manufacture of the fluid device.

  First, an embodiment of the silicone member and the method for producing the same according to the present invention will be described. In FIG. 1, the permeation | transmission top view of a fluid device provided with the silicone member of this invention is shown. FIG. 2 shows a II-II sectional view of the fluidic device. FIG. 3 shows a III-III cross-sectional view of the fluidic device. In this embodiment, the silicone member of the present invention is embodied as the lower member of the fluidic device.

  As shown in FIGS. 1 to 3, the fluidic device 1 includes an upper member 10 and a lower member 20. The upper member 10 and the lower member 20 are stacked in the vertical direction. The upper member 10 is made of polydimethylsiloxane (PDMS) and has a rectangular plate shape. An upper recess 11 is formed on the lower surface of the upper member 10. An introduction hole 12 is formed in the front end portion of the upper member 10. The introduction hole 12 penetrates the upper member 10 in the vertical direction.

  The lower member 20 is made of PDMS and has a rectangular plate shape. The flow path 14 is defined by the lower surface of the upper member 10 and the upper surface of the lower member 20. The upstream end of the flow channel 14 communicates with the introduction hole 12. At the downstream end of the flow path 14, a discharge port 13 that opens to the rear surface is disposed.

  Near the center of the upper surface of the lower member 20, seven groove-shaped lower recesses 21 are formed. Each of the lower concave portions 21 has a linear shape extending in the left-right direction. The lower recesses 21 are arranged in parallel at a predetermined interval in the front-rear direction. The cross section in the vertical direction of the lower recess 21 has a rectangular shape. The upper surface of the lower member 20 that defines the flow path 14 includes a lower recess 21 and other flow path portions 22.

  A hydrophilic layer 210 is disposed on the surface of the lower recess 21. The hydrophilic layer 210 is a silicon oxide film containing an organic component. Thereby, the lower side recessed part 21 has hydrophilicity in all the side surfaces and bottom surfaces. The hydrophilic layer 210 is disposed on the entire upper surface of the lower member 20 including the lower recess 21.

  A hydrophobic layer 220 is disposed on the surface of the flow path portion 22. The hydrophobic layer 220 is a fluororesin film. The hydrophobic layer 220 is disposed so as to cover the upper surface of the hydrophilic layer 210. Thereby, the flow path part 22 has hydrophobicity. In the present embodiment, the upper surface of the lower member 20 that defines the flow path 14 is composed of a hydrophilic lower concave portion 21 and a hydrophobic flow path portion 22.

  The fluid injected from the introduction hole 12 flows through the flow path 14 and is discharged from the discharge port 13. For example, when a hydrophilic solution is flowed as a sample, since the lower concave portion 21 has hydrophilicity, a part of the solution can be reliably captured in the lower concave portion 21. On the other hand, the flow path part 22 has hydrophobicity. For this reason, the solution is unlikely to adhere to the flow path portion 22. Therefore, sample loss is reduced and analysis accuracy is improved.

  The manufacturing method of the fluid device 1 is as follows. FIG. 4 shows a hydrophilization process in manufacturing the lower member of the fluidic device. FIG. 5 shows a hydrophobization step in manufacturing the lower member of the fluidic device. FIG. 6 shows a lamination process of the upper member and the lower member.

  First, as shown in FIG. 4, one surface 200A of the base material 20A to be the lower member 20 is irradiated with the microwave plasma P in an atmosphere containing a silane-based gas, and the one surface 200A is oxidized with silicon containing an organic component. A material film is formed. As a result, the hydrophilic layer 210 is formed on the entire surface 200A including the recess 21A. Next, as shown in FIG. 5, the substrate 20 </ b> A is inverted and the one surface 200 </ b> A on which the hydrophilic layer 210 is formed is pressed against the stamp member 30. The stamp member 30 is impregnated with a fluororesin liquid 300. Thereby, the fluororesin liquid adheres to the surface of the hydrophilic layer 210 other than the concave portion 21A of the base 20A. Thereafter, the attached fluororesin liquid is dried to form a fluororesin film as a hydrophobic layer on the surface of the hydrophilic layer 210 other than the recess 21A. In this way, as shown in FIG. 6, the lower member 20 having the hydrophilic layer 210 and the hydrophobic layer 220 is manufactured. Then, as shown by a hollow arrow in FIG. 6, the upper member 10 and the lower member 20 are overlapped to manufacture the fluid device 1 shown in FIG.

  As mentioned above, although one Embodiment of the fluid device provided with the silicone member of this invention was shown, the structure of a fluid device is not limited to the said form. For example, the material of the mating member laminated on the silicone member of the present invention may be fluororesin or glass in addition to PDMS. The shape and size of the mating member are not limited at all. The silicone member and the mating member of the present invention may be simply laminated, but may be bonded using an adhesive or the like.

  Further, the silicone member for a fluid device and the method for producing the same according to the present invention are not limited to the above-described embodiments, and various modifications and improvements that can be made by those skilled in the art are possible without departing from the gist of the present invention. It can be implemented in the form. Next, the silicone member of the present invention and the manufacturing method thereof will be described in detail.

<Silicone for fluid devices>
The silicone member of the present invention is an integral body made of silicone, and one surface that comes into contact with a fluid is composed of a recess for capturing a part of the fluid and a channel portion other than that. The type of fluid is not particularly limited. The fluid may be hydrophilic or hydrophobic. For example, when a hydrophilic fluid flows on one surface, a part of the fluid is trapped in the recess. A part of the fluid may be a part of the fluid itself, or may be only a specific substance contained in the fluid.

  The size, shape, and arrangement of the recesses are not particularly limited. For example, the recess may be a groove or a depression. The cross section in the depth direction of the concave portion may be a rectangular shape such as a square, a rectangle or a trapezoid, a curved shape such as a semicircle or an ellipse, or a V shape. At least a part of the recess has hydrophilicity. That is, the entire concave portion may be hydrophilic, or only the bottom surface may be hydrophilic depending on the shape of the concave portion, and a part of the side surface may be hydrophilic. In addition, when the whole recessed part is hydrophilic, only a flow-path part becomes hydrophobic.

  A hydrophilic layer is disposed on the surface of the recess having hydrophilicity. The hydrophilic layer may be formed by surface modification or may be formed by forming a film on the surface. For example, the surface is modified so that a hydroxyl group, an amino group, a C—N bond, a C═O bond, an amide bond (O═C—N), or the like is added. Moreover, the form by which hydrophilic thin films, such as the silicon oxide film and titanium oxide containing an organic component, were formed in the surface is mentioned. The hydrophilic thin film may be a monomolecular film. In addition, the hydrophilic layer formed only by surface modification may swell when contacted with an organic solvent for a long time. Therefore, a hydrophilic thin film is desirable as the hydrophilic layer.

  The part which does not have hydrophilicity among a recessed part, and a flow-path part have hydrophobicity. The hydrophobicity may be the hydrophobicity of silicone itself, or may be imparted by surface modification or film formation on the surface. In the latter case, a hydrophobic layer is disposed on the surface. The hydrophobic layer is desirably disposed on the surface of the flow path portion. As the hydrophobic layer, a hydrophobic thin film such as a fluororesin film or a silicone film is suitable.

<Method for producing silicone member for fluidic device>
The manufacturing method of the silicone member for fluid devices of this invention has a hydrophilization process and a hydrophobization process. Hereinafter, each process will be described.

[Hydrophilization process]
This step is a step of forming a hydrophilic layer on the entire surface of the silicone substrate having a recess on one surface by treating the one surface with at least one of plasma CVD and plasma irradiation.

  A substrate having a recess on one side may be manufactured by injection molding of silicone or the like. Further, after forming the base material, one surface may be processed to form a recess.

  The hydrophilic treatment for imparting hydrophilicity to the entire surface is performed by at least one of a plasma CVD method and plasma irradiation. In either method, plasma is generated in a predetermined gas atmosphere. The method for generating plasma is not particularly limited. For example, RF plasma using a high frequency (RF) power source or microwave plasma using a microwave power source may be employed. The treatment pressure may be about 1 to 100 Pa.

  For example, a hydrophilic silicon oxide film containing an organic component may be formed by irradiation with microwave plasma in an atmosphere of tetraethoxysilane (TEOS) gas and argon gas (plasma CVD method). Alternatively, hydrophilic functional groups may be imparted to one surface of the substrate by irradiation with microwave plasma in an atmosphere of an amine gas such as ethylenediamine, diethylamine, or ammonia and a carrier gas such as argon or nitrogen.

[Hydrophobicization process]
This step is a step of forming a hydrophobic layer on the surface of the hydrophilic layer other than the concave portion in one surface subjected to the hydrophilic treatment. By this step, hydrophobicity is imparted to one surface other than the concave portion, that is, the flow path portion. The method for forming the hydrophobic layer is not particularly limited. For example, the surface of the hydrophilic layer may be modified or a hydrophobic resin film may be formed on the surface. Examples of the hydrophobic resin film include a fluororesin film and a silicone film. As a method for forming the hydrophobic resin film, a transfer method in which the surface of the substrate on which the hydrophilic layer is formed is pressed against a member having the hydrophobic resin liquid to transfer the hydrophobic resin liquid to the surface of the hydrophilic layer is preferable. It is.

  Next, the present invention will be described more specifically with reference to examples.

<Manufacture of silicone members>
[Example 1]
A silicone member having the same shape as the lower member shown in FIGS. 1 to 3 was manufactured. The length (width) in the front-rear direction of the recess is 6 μm, the length in the left-right direction is 5 mm, the depth is 10 μm, and the distance between the recess and the recess is 10 μm (see FIG. 1).

  First, PDMS was injection-molded to produce a plate-like substrate having a predetermined recess on the upper surface. Next, a silicon oxide film containing an organic component was formed on the entire upper surface of the substrate by a microwave plasma CVD method. Film formation was performed in an atmosphere of 10 Pa of argon gas and 1.0 Pa of TEOS gas with a microwave frequency of 2.45 GHz and an output power of 1 kW. The film formation time was 60 seconds. The formed silicon oxide film (hydrophilic layer) containing an organic component had a thickness of 75 nm. Subsequently, 1 mL of a fluororesin liquid (“CYTOP (registered trademark)” manufactured by Asahi Glass Co., Ltd.) was impregnated into a plate-shaped melamine foam stamp member having a thickness of 0.2 mm. Then, the upper surface of the base material was pressed against the stamp member, and the fluororesin liquid was transferred to a portion other than the concave portion. Then, it was made to dry for 30 minutes at room temperature, and the fluororesin film | membrane (hydrophobic layer) was formed in parts other than a recessed part. The resulting silicone member is referred to as the silicone member of Example 1.

[Example 2]
An amino group was imparted to the upper surface of the same substrate used in Example 1 by microwave plasma treatment. The upper surface to which the amino group is added becomes a hydrophilic layer. The microwave plasma treatment was performed in an atmosphere of argon gas of 10 Pa and ethylenediamine gas of 1.0 Pa with a microwave frequency of 2.45 GHz and an output power of 1 kW. The processing time was 60 seconds. Subsequently, the upper surface of the substrate was pressed against the stamp member used in Example 1, and the fluororesin liquid was transferred to portions other than the recesses. Then, it was made to dry for 30 minutes at room temperature, and the fluororesin film | membrane (hydrophobic layer) was formed in parts other than a recessed part. The resulting silicone member is referred to as the silicone member of Example 2.

[Comparative Example 1]
A silicone member was produced in the same manner as in Example 1 except that the fluororesin film was not formed on the portion other than the recess. The obtained silicone member is referred to as the silicone member of Comparative Example 1. In the silicone member of Comparative Example 1, a silicon oxide film (hydrophilic layer) containing an organic component is formed on the entire upper surface (including the recesses).

[Comparative Example 2]
The base material itself used in Example 1 was used as the silicone member of Comparative Example 2.

<Measurement of water contact angle>
The water contact angle of the upper surface of the manufactured silicone member was measured. The water contact angle was measured at two locations of the concave portion and the other flat portion. The flat portion includes a flow path portion in the fluid device described later. The water contact angle was measured according to JIS R3257: 1999. In this example, 2 μl of water was dropped on the surface of the measurement object, and the water contact angle within 1 minute after the water contacted was measured. Table 1 shows the measurement results of the water contact angle.

  As shown in Table 1, in the silicone member of Example 1, the water contact angle of the concave portion was 60 °, and the water contact angle of the flat portion was 110 °. Thereby, it was confirmed that the recessed part of the silicone member of Example 1 has hydrophilicity, and the flat part has hydrophobicity. In the silicone member of Example 2, the water contact angle of the recess was less than 10 °, and the water contact angle of the flat portion was 110 °. Thereby, it was confirmed that the recessed part of the silicone member of Example 2 has hydrophilicity, and the flat part has hydrophobicity. On the other hand, in the silicone member of Comparative Example 1, the water contact angle of both the concave portion and the flat portion was 60 °, and it was confirmed that the entire upper surface was hydrophilic. Moreover, in the silicone member of the comparative example 2, the water contact angle of both the recessed part and the flat part was 110 degrees, and it was confirmed that the whole upper surface has hydrophobicity derived from PDMS.

<Manufacture of fluid devices>
Using the manufactured silicone member, a fluid device having the form shown in FIGS. 1 to 3 was manufactured. The manufactured fluid device has a longitudinal length of 50 mm and a lateral length of 10 mm (see FIG. 1). The upper member was separately manufactured by injection molding PDMS. The depth of the upper concave portion defining the flow path is 150 μm. The upper member was laminated on the upper surface of the manufactured silicone member (lower member), and both were joined. The fluid device manufactured in this manner is referred to as a fluid device of Example 1 corresponding to the number of the silicone member.

<Performance evaluation>
[Evaluation method]
The test solution was poured into the flow path of the fluid device, and the trapping property in the recess was evaluated. First, 10 mL of an aqueous dye ("Stamp Ink S-1" manufactured by Shachihata Co., Ltd.), 5 mL of pure water, and 5 mL of ethanol were mixed to prepare a test solution. Next, 4 μL of the test solution was injected from the introduction hole of the fluid device using a micropipette. Then, the front end of the fluid device was lifted and tilted by 30 ° from the horizontal to discharge the flow path reagent from the outlet. Then, the residue in the recessed part and flow path part of a lower side member (silicone member) was confirmed. The residue was confirmed using a digital microscope “VHX-100” manufactured by Keyence Co., Ltd. When the dye component residue was observed, the residue was present. And it was evaluated that the trapping property was good only when there was a residue in the recess and there was no residue in the flow path portion, and the trapping property was evaluated otherwise. The water evaporation rate in a 50% humidity environment is 0.07 μL / min. For this reason, the water in the test solution does not remain because it evaporates.

[Evaluation results]
Table 1 summarizes the evaluation results of the trapping property of the recesses. As shown in Table 1, in the fluid devices of Examples 1 and 2, there was a residue in the recess and no residue in the flow path. That is, in the fluid devices of Examples 1 and 2, it was confirmed that the trapping property was good (indicated by a circle in Table 1). On the other hand, in the fluid device of Comparative Example 1, there was a residue not only in the recess but also in the flow path. This means that the sample is likely to adhere to the flow path portion, so that the capturing property was judged to be poor (indicated by x in Table 1). Moreover, in the fluid device of Comparative Example 2, there was no residue in the recess. In this case, since a part of the sample could not be captured, it was determined that the capture performance was poor.

1: fluid device, 10: upper member, 11: upper recess, 12: introduction hole, 13: discharge port, 14: flow path, 20: lower member (silicone member for fluid device), 20A: base material, 21: Lower concave part, 21A: concave part, 22: flow path part, 200A: one side, 210: hydrophilic layer, 220: hydrophobic layer, 30: stamp member, 300: fluororesin liquid, P: microwave plasma.

Claims (9)

One surface made of silicone and in contact with the fluid is composed of a recess for capturing a part of the fluid and a channel portion other than that.
A silicone member for a fluid device, wherein at least a part of the concave part is hydrophilic, and the concave part and the flow path part other than the part are hydrophobic.   The fluidic device silicone member according to claim 1, wherein a hydrophilic layer is disposed on the hydrophilic surface of the concave portion.   The fluidic device silicone member according to claim 2, wherein the hydrophilic layer is a silicon oxide film containing an organic component.   The fluidic device silicone member according to any one of claims 1 to 3, wherein a hydrophobic layer is disposed on a surface of the flow path portion.   The fluidic device silicone member according to claim 4, wherein the hydrophobic layer is a fluororesin film. It is a manufacturing method of the silicone member for fluid devices according to claim 1,
A hydrophilization step of forming a hydrophilic layer on the entire surface by treating the one surface with at least one of a plasma CVD method and plasma irradiation on a silicone substrate having a recess on the one surface;
A hydrophobizing step of forming a hydrophobic layer on the surface of the hydrophilic layer other than the concave portion of the one surface;
The manufacturing method of the silicone member for fluid devices characterized by having.   The method for producing a silicone member for a fluid device according to claim 6, wherein the hydrophilization step is a step of forming a silicon oxide film containing an organic component on the entire surface by the plasma CVD method.   The method for producing a silicone member for a fluid device according to claim 6 or 7, wherein the hydrophobizing step is a step of forming a hydrophobic resin film by a transfer method.   The method for producing a silicone member for a fluid device according to claim 8, wherein the hydrophobic resin film is a fluororesin film.

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