Gokarneshan et al., J Fashion Technol Textile Eng 2015, 3:2
http://dx.doi.org/10.4172/2329-9568.1000121
Journal of Fashion
Technology &
Textile Engineering
Review Article
Characterization Methods of
Nano Textile Materials
Gokarneshan N*, Gopalakrishnan PP and Anitha Rachel D
Abstract
Nano materials are being used in textile finishing to impart
functional properties to the fabrics. This paper deals with the
characterization aspect of important nano materials used in textile
finishing, viz., titanium dioxide, silver oxide and zinc oxide. Each
type of nano material produces its own distinct effect on the fabrics
so treated. Various techniques are being used for characterizing
the nano particles. These are discussed in detail in this paper.
The characterization techniques enable to study the surface
characteristics of treated fabrics and also measure the nano
particle size.
Keywords: Characterization; Nano particles; Silver oxide’
Titanium dioxide; Zinc oxide
Introduction
Nano plastic and nanostructured materials are attracting a
great deal of attention of the textile and polymer researchers and
industrialists because of their potential applications for achieving
specific processes and properties, especially for functional and
high performance textile applications [1]. This paper deals with the
characterization methods of the important nano materials used
in textile finishing. The important nano materials include silver
oxide, zinc oxide and titanium dioxide. Silver oxide is well known
to imparting antimicrobial properties to the fabrics so treated. Zinc
oxide is known for UV protection for fabrics, and titanium dioxide
is used for wrinkle resistance. Besides these basic properties, the
various nano materials are also used to impart other functional
properties. The techniques used are uv absorption spectroscopy,
FTIR spectroscopy, and X-ray diffraction, and scanning electron
microscopy (SEM) studies. The SEM technique has been used for
the investigation of textile materials [2-5]. It can also be used to view
dispersion of nano particles such as carbon nanotubes, nanoclays,
and hybrid POSS Nanofillers in the bulk and on the surface of nano
composite fibres and coatings on yarns and fabric samples [6,7]. The
uv absorption spectroscopy has been used to evaluate the uv shielding
effectiveness of fabrics. FTIR spectroscopy has been used to evaluate
the chemical composition of nano particles and X-ray diffraction is
used to evaluate the crystallinity of nano particles.
Characterization of Silver Oxide Nano Particles
Recent studies have shown that silver nanoparticles with
*Corresponding author: Dr. N. Gokarneshan, NIFT TEA College of
knitwear fashion, Tirupur 641 606, India, Tel: 0421 237 4200; E-mail:
advaitcbe@rediffmail.com
Received: April 11, 2015 Accepted: February 23, 2015 Published: February
27, 2015
International Publisher of Science,
Technology and Medicine
a SciTechnol journal
less than 50nm size, which are normally used for textile finishing can
cause toxic effects on human health and environment [8,9]. Hence
it is necessary to produce silver nano particles of > 50nm size for
textile applications. In one of the method described, the presence of
silver in nano meter size has been qualitatively confirmed by the use
of shimadzu UV 1601 spectrometer. An absorption peak ranging in
wave length between 400-440 nm could be produced by silver having
a nano meter size. The concentration of silver in the synthesized
powder has been analyzed using atomic absorption spectrum with
Varian spectra 220. The size of the silver nano particles in the nano
powder has been determined by means of transmission electron
microscope (TEM) analysis using Philips CM 200 model machine
by drop coating method. The nano powder was dissolved in the
water and drop coated on the copper grids for TEM analysis. The
transmission electron microscope has been attached with energy
dispersive analysis of X-rays device so as to enable elemental analysis
on the individual nano particles [10].
UV Spectra
In the case of Ultraviolet (UV) Spectroscopy, a reference beam
in the spectrometer travels from the light source to the detector
without interacting with the sample. The sample beam interacts with
the sample exposing it to ultraviolet light of continuously changing
wavelength. When the emitted wavelength corresponds to the energy
level which promotes an electron to a higher molecular orbital,
energy is absorbed. The detector records the ratio between reference
and sample beam intensities. The computer determines at what
wavelength the sample absorbed a large amount of ultraviolet light by
scanning for the largest gap between two the two beams. When a large
gap between intensities is found, where the sample beam intensity is
significantly weaker than the reference beam, the computer plots this
wavelength as having the highest ultraviolet light absorbance when
it prepares the ultra violet absorbance spectrum. In certain metals,
such as silver and gold, the Plasmon resonance is responsible for
their unique and remarkable optical phenomena. Metallic (silver or
gold) nano particles, typically 40-100 nm in diameter, scatter optical
light elastically with remarkable efficiency because of a collective
resonance of the conduction electrons in the metal known as surface
Plasmon resonance. The surface plasma resonance peak in UV
absorption spectra is shown by these plasmon resonant particles.
The magnitude, peak wave length, and spectral bandwidth of the
Plasmon resonance associated with a nano particle are dependent on
the particle’s size, shape and material composition as well as the local
environment. Besides biological labeling and nanoscale biosensing
silver nano particles have received considerable attention to the
textile and polymer researchers due to their attractive anti microbial
properties. The surface Plasmon resonance peak in absorption
spectra of silver particles is shown by absorption of maximum at 420500 nm. The surface peaks vary with size, shape and concentration
of the metallic nano particles. Figure 1 shows how the value of
absorbance is shifted towards higher wavelengths with increasing Ag
content in a silver nano particle/kaolinite composites. It is reported
that the truncated triangular silver nano particles with a lattice plane
as the basal plane displayed the strongest biocidal action compared
with spherical, rod shaped nanoparticles or with Ag+ (in the form of
All articles published in Journal of Fashion Technology & Textile Engineering are the property of SciTechnol, and is protected
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Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
Figure 1: UV absorption spectrum of 5x10-4 M and spectra of Ag solution
and spectra of suspensions of Ag/Kaolinite samples at different silver
contents [11] electrons in a metal.
AgNO3) [11]. This shape of silver nanoparticles can be identified by
observing the corresponding peak. TEM images of the corresponding
particle are shown above their respective spectrum. This example is a
representative of the principle conclusion that the peak shifts as per
the particle shape and the triangular shaped particles appear mostly
red, particles that form the pentagon appear green and the blue
particles are spherical.
The optical absorption spectra of metal nano particles shift to
longer wavelengths with increasing particle size, the position and
shape of th Plasmon absorption of silver nano particles are strongly
dependent on the particle size, dielectric medium, and surface
adsorbed species [12,13]. According to mis’s theory, only a single
surface Plasmon resonance (SPR) band is expected in the absorption
spectra of spherical nanoparticles, whereas anisotropic particles could
give rise to two or more SPR bands depending on the shape of the
particles. The number of SPR peaks increases as the symmetry of the
nano particle decreases [14]. Thus spherical nano particles, circular
disks and triangular nano plates of silver show one, two and more
peaks respectively.
ultra thin specimen and interacts as it passes through the sample.
An image is formed from the electrons transmitted through the
specimen, magnified and focused by an objective lens and appears
on an imaging screen. The sample interacts with the electron beam
mostly by diffraction rather than by absorption. The intensity of
diffraction depends on the orientation of the planes of atoms in a
crystal relative to the electron beam. At certain angles the electron
beam is diffracted strongly from the axis of the incoming beam, while
at other angles the beam is largely transmitted. Modern TEMs are
equipped with specimen holders that allow to tilt the specimen to
a range of angles in order to obtain specific diffraction conditions.
Therefore, a high contrast image can be formed by blocking electrons
deflected away from the optical axis of the microscope by placing the
aperture to allow only unscattered electrons through. This produces
a variation in the electron intensity that reveals information on the
crystal structure. The specimens must be prepared as a thin foil so
that the electron beam can penetrate. Materials that have dimensions
small enough to be electron transparent, such as powders or nano
tubes, can be quickly produced by the deposition of a dilute sample
containing the specimen onto support grids. As polymeric nano
composites or the textile samples are not as hard as metals, they are
cut into thin films (<100 nm) using ultra- microtome with diamond
knife at cryogenic condition (in liquid nitrogen).
The TEM is used widely both in material science/metallurgy and
biological sciences. In both cases the specimens must be very thin and
able to withstand the high vacuum present inside the instrument. For
biological specimens, the maximum specimen thickness is roughly
1 micrometer. To withstand the instrument vacuum, biological
specimens are typically held at liquid nitrogen temperatures after
embedding in vitreous ice, or fixated using a negative staining
material such as uranyl acetate or by plastic embedding.
The properties of nano composites depend to a large extent on
successful nano level dispersion or intercalation/ exfoliation of nano
clays, therefore monitoring their morphology and dispersion is very
crucial [16]. TEM images reveal the distribution and dispersion of
nano particles in polymer matrices of nano composite fibres, nano
coatings etc. the extent of exfoliation, intercalation and orientation
of nano particles can also be visualized using the TEM micrograph
(Figure 3).
Energy Dispersive X-ray (EDX) analysis is a technique to analyze
near surface elements and estimate their proportion at different
position, thus giving an overall mapping of the sample. It is used in
The
UV-Visible
spectra
of
the
produced
Polyvinylpyrrolidone coated silver nano particles in both powder and
solution form are shown in Figure 2. A clear absorption peak at a
wave length of 430 nm has been observed for the spectra obtained
in both solution and powder forms, owing to the presence of silver
nano particles [15]. The UV-visible spectroscopy is an established
method for the confirmation of formation of silver nano particles in
solution. An intense absorption peak is produced at 400 nm, by the
silver nano particles, which arises from surface Plasmon excitation.
Surface Plasmon excitation describes the collective excitation of the
conduction electrons in a metal.
TEM and EDAX studies
Transmission electron microscopy (TEM) is a microscopy
technique whereby a beam of electrons is transmitted through an
Volume 3 • Issue 2 • 1000121
Figure 2: UV visible Spectra of PVP coated silver (a) nano particles in
solution (b) nano powder [15].
• Page 2 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
conjunction with scanning electron microscope an electron beam
strikes the surface of a conducting sample. The energy of the beam is
typically in the range of 10-20 ekV. This causes X-rays to be emitted
from the material. The energy of the X-rays emitted depends on the
material under examination. The X-rays are generated in a region
about 2 microns in depth, and thus EDX is not truly a surface science
technique. By moving the electron beam across the material an
image of each element in the sample can be obtained. Due to the low
X-ray intensity, images usually take a number of hours to acquire.
The composition or the amount of nanoparticles near and at the
surface can be estimated using the EDX, provided they contain some
heavy metal ions. For example, the presence of gold, palladium, and
silver nano particles on surface can easily be identified using EDX
technique. Elements of low atomic number are difficult to detect by
EDX. The Si-Li detector protected by a beryllium window cannot
detect elements below atomic number of 11. In windowless systems,
the elements with as low atomic number as 4, can be detected. EDX
spectra have to be taken by focusing the beam at different regions
of the same sample to verify spatially uniform composition of the
bimetallic materials. The incorporation of silver nano particles on
cotton cloth can be verified by EDX [17,18].
The TEM image of PVP Coated silver nano particles is shown
in Figure 3. The silver nano particles ranged in size between 50
-60nm. As can be observed from the Figure 3, there appear a few
big agglomerates of nano particles having size range between 100200nm [15]. This could be attributed to the thermal migration of
nano particles during the drying process in the spray dryer. EDAX
has been used for analyzing the various sizes of nano particles
presented by TEM image. Figure 4a shows the spectrum at a place
having no nano particles, while Figures 4b-d indicates the places
having nano particles with sizes of 55, 100 and 200 nm respectively.
All the four spectra confirm the presence of Silver nano particles in
the synthesized powder. The low intensity peak pertaining to silver
in the first spectra is attributed to the presence of silver traces in the
polymer matrix. The peak related to copper in all the spectra is due to
the use of copper grids in TEM analysis.
Characterization of Zinc Oxide Nano Particles
UV absorption properties
Zinc oxide nano particles have been used for imparting
antibacterial and UV blocking properties [19-21]. Besides, they are
also unique in their photo-catalytic, electrical, electronic, optical, and
dermatological properties [22-28]. The UV-screen properties of the
Figure 4: EDX Spectra of (a) Polymer matrix without nano particles (b) at 55
nm Size nano particles (C) at 100 nm size particles (d) at 200 nm size nano
particles [15].
treated fabrics were investigated by absorption spectroscopy using
a UV–Vis spectro photometer (Perkin –Elmer Lamda 35 equipped
with 60mm integrating sphere). The blank reference was air. The
UV profiles of untreated samples were compared with the spectra
collected from the same fabrics treated with ZnO nano particles,
and the effectiveness in shielding UV radiation was evaluated by
measuring the UV absorption, transmission and reflection. Each
measurement is the average of four scans obtained by rotating the
sample by 90 °C. The transmission was used to calculate the ultraviolet
protection factor (UPF) and the percent UV transmission, using the
following equations.
λ2
λ2
λ1
λ1
∫
∫ E ( λ ) S ( λ ) ∗ Td (λ )
UPF =
E (λ ) S (λ ) ∗ d λ
UV trasmission
=
(%)
λ2
T (λ )
∑
λ
λ2 − λ1
(1)
(2)
1
Where E(λ) is the relative erythemal spectral effectiveness ; S(λ),
the solar spectral irradiance in W m-2 nm-1; and T(λ), the spectral
transmission of the specimen obtained from UV spectrophometric
experiments. The values of E(λ) and S(λ) were obtained from
the national Oceanic and Atmospheric Administration database
(NOAA). The UPF values were calculated both for UV-A (315-400
nm) and for UV-B (295-315 nm). The percent UV transmission,
obtained from equation (2), was determined for UV-A and UV-B
radiations from the transmission spectra of the fabric samples.
Physical and Physico-chemical characterization
FTIR spectroscopy [29,30] has been used to evaluate the chemical
composition of synthesized ZnO nano particles. X ray diffraction has
been used to determine the crystallinity of nano particles. Dried ZnO
nano particles weighing 0.5 grams has been deposited as randomly
oriented powder onto a plexiglass sample container, and XRD pattern
were recorded between 20° and 80° angles, with a scan rate of 1.5° per
minute. The crystallite domain diameter (D) was obtained from XRD
peaks using the Scherrer’s equation
D=0.89 * λ / ∆W *cosθ
Figure 3: The TEM image of PVP coated silver nano particles [15].
Volume 3 • Issue 2 • 1000121
Where λ is the wavelength of incident X-ray beam; θ the Bragg’s
diffraction angle; and ∆W the width of the X-ray pattern line at halfpeak height in radians. TEM has been used to obtain the shape and
• Page 3 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
size of nano particles. The samples have been placed on carbon coated
copper grids for TEM measurement. These samples were prepared
from much diluted dispersion of particles in 2-propanol. The ZnO
treated fabrics were analyzed through Scanning Electron Microscopy
(SEM). The samples were previously coated with a thin layer of gold
deposited sputtering under vacuum.
FTIR and XRD studies
Fourier Transform Infra Red (FTIR) spectroscopy is a technique
which is used to obtain an infra red spectrum of absorption, emission,
photoconductivity or Raman Scattering of a solid, liquid or gas. An
FTIR spectrometer simultaneously collects spectral data in a wide
spectral range. This confers a significant advantage over a dispersive
spectrometer which measures intensity over a narrow range of
wavelengths at a time. The FTIR spectra of the synthesized zinc oxide
nano materials are shown in Figure 5. The spectrum relating to the
first method of synthesis can be observed to be in the absorption
band near 430 cm-1. The peaks observed at 3450 and 2350 cm-1 show
that C=O and –OH residues are present, which could be attributed
to carbon dioxide and atmospheric moisture respectively. The same
spectrum has also been obtained from the zinc oxide nano material
obtained from the second method of synthesis. The images of the
nano particles obtained from Transmission Electron Microscope
(TEM) are shown in Figure 6. It can be seen that the nano particles are
almost spherical and somewhat mono dispersed [31]. However, some
larger aggregates are present in the treated fabric, as obtained from the
first method of synthesis (Figure 6a). This is due to the high surface
energy of the zinc oxide nano particles, which cause the aggregation,
particularly when the synthesis of the nano particle is done under
aqueous medium [32]. The nano particles obtained from the second
method of synthesis are more mono dispersed and isolated than those
obtained from the first method of synthesis. Thus the second method
of synthesis gives a greater peptization than that of the first one. From
Figure 6b, it can be seen that some halos envelope the nano particles
owing to the retention of some diol that remains adsorbed on the
ZnO nano particles, and produces tiny peaks at 2850- 2920 cm-1 in
the FTIR spectrum as shown in Figure 5b.
X-rays are electromagnetic radiation similar to light but with
a much shorter wavelength. They are produced when electrically
charged particles of sufficient energy are decelerated. In an X-ray tube,
the high voltage maintained across the electrodes draws electrons
towards a metal target (the anode). X ray pre produced at the point of
impact, and radiate in all directions
Figure 5: FTIR Spectrum of ZnO nano particles obtained from (a)
synthesis 1 and (b) Synthesis 2 [32].
Volume 3 • Issue 2 • 1000121
Figure 6: TEM micrographs of the materials obtained from (a)
synthesis 1 and (b) synthesis 2 after three peptizations [32].
If an incident X ray beam encounters a crystal lattice, general
scattering occurs although most scattering interferes with itself
and is eliminated (destructive inference), diffraction occurs when
scattering in a certain direction is in phase with scattered rays from
other atomic planes. Under this condition the reflections combine
to form new enhanced wave fronts that mutually reinforce each
other (constructive inference). The relation by which diffraction
occurs is known as the Bragg’s law or equation. As each crystalline
material including the semi crystalline polymers as well as metal
and metal oxide nanoparticles and layered silicate nanoclays have
a characteristic atomic structure, it will diffract X rays in a unique
characteristic diffraction order or pattern.
X ray diffraction data form polymers generally provide
information about crystallinity, crystallite size, orientation of the
crystallites and phase composition in semi crystalline polymers. With
appropriate accessories, X-ray diffraction instrumentation can be
used to study the phase change as a function of stress or temperature,
to determine lattice strain, to measure the crystalline modulus, and
with the aid of molecular modeling to determine the structure of
polymer.
Besides the above mentioned characterization this sophisticated
technique can also be used to characterize polymer-layered silicate
(clay) nanocomposites. Polymer / layered silicate nanoclay composites
have attracted great interest, both in industry and in academia,
because theyoften exhibit remarkable improvement in materials
properties at very low clay content (3-6 wt%) when compared with
virgin polymer or conventional composites. The use of organoclays
as precursors to nanocomposite formation has been extended into
various polymer systems (thermoset and thermoplastic) including
epoxy and others.
For true nano composites, the clay nanolayers must be uniformly
dispersed and exfoliated in the polymer matrix. The structure of
polymer / layered silicates composites has typically been established
using wide angle X-ray Diffraction (WAXD) analysis. By monitoring
the position shape and intensityof the basal reflections from the
distributed silicate layers, the nanocomposite structures (intercalated
or exfoliated) may be identified. In an exfoliated nanocomposite, the
extensive layer separation associated with the delamination of the
original silicate layers in the polymer matrix results in the eventual
disappearance of any coherent X ray diffraction from the distributed
silicate layers. On the other hand, for intercalated nano composites,
the finite layer expansion associated with the polymer intercalation
results in the appearance of a new basal reflection corresponding to
the larger gallery height.
Organophilic clay (also known as nanoclay) can be obtained by
• Page 4 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
simply the ion exchange reaction of the hydrophilic clay with an
organic cation such as an alkyl ammonium or phosphonium ion
to make it compatible with polymeric matrix. The inorganic ions,
relatively small (sodium) re exchanged with more voluminous organic
onium ions. This ion exchange reaction results in widening the gap
between the single sheets, enabling organic cations chain to move
in between them. This increase in d-space or degree of exfoliation of
the polymer nanocomposites can be obtained from Bragg’s equation.
This X-ray diffractograms of the organoclay reveals a shift in the
position of [001] planes (2θ changed from 5.7o to 4.32o) indicating an
increase in the basal spacing of these planes. The increase is relatively
large from 1.5nm to 2.06nm and confirms the occurrence of organic
molecule intercalation between silicate platelets.
The X-ray diffraction spectra of the zinc oxide nano materials
can be seen in Figure 7. The spectra exhibit well defined peaks
typical of zinc oxide in the crystal structure of zincite. This indicates
crystallinity of synthesized solids. The effects of the particle size cause
broadening of the peaks in the X-ray diffraction pattern of solids. The
mean crystallite size of a powder sample has been estimated from the
full width at half maximum of the diffraction peak (∆W) according
to the Scherrer’s equation. The values of ∆W for the first and second
methods of synthesis are 0.0087 and 0.017 radians respectively. Thus
using the Scherrer’s equation, the average sizes of the nano particles
synthesized by the first and second methods of synthesis are 20+5
nm and 10+1 nm respectively [33-35]. The important feature of the
x-ray diffraction patterns is that the peaks from the second method
of synthesis (Figure 7b) are broader than the peaks from the first
method of synthesis (Figure 7a). This result suggests that the particles
obtained from the second method of synthesis are smaller than the
particles obtained from the first method of synthesis as confirmed
by TEM micrographs (Figure 6), and reflects the effects due to the
experimental conditions on the nucleation and growth of the crystal
nuclei. The morphology and size of the nano particles are greatly
influenced by the experimental conditions. Interestingly when
the reaction temperature in water is raised from 90 °C, to that in
1,2-ethanediol, to 150 °C, the nano particle size gets reduced from 20
to 9 nm.
Electron Microscopy
The Scanning Electron Microscope (SEM) is an electron
microscope that images the sample surface by scanning it with a
high energy beam of electrons. Conventional light microscopes use
a series of glass lenses to bend light waves and create a magnified
image while the scanning electron microscope creates the magnified
images by using electrons instead of light waves [2]. When the
beam of electrons strikes the surface of the specimen and interacts with
the atoms of the sample, signals in the form of secondary electrons,
back scattered electrons and characteristic X-rays are generated
that contain information about the sample's surface topography,
composition, etc. The SEM can produce very high-resolution images
of a sample surface, revealing details about 1-5 nm in size in its
primary detection mode i.e. secondary electron imaging. Characteristic
X-rays are the second most common imaging mode for an SEM. These
characteristic X-rays are used to identify the elemental composition of
the sample by a technique known as energy dispersive X-ray (EDX).
Back-scattered electrons (BSE) that come from the sample may also
be used to form an image. BSE images are often used in analytical SEM
along with the spectra made from the characteristic X-rays as clues to
the elemental composition of the sample.
In a typical SEM, the beam passes through pairs of scanning
coils or pairs of deflector plates in the electron column to the final
lens, which deflect the beam horizontally and vertically so that it
scans in a raster fashion over a rectangular area of the sample surface.
Electronic devices are used to detect and amplify the signals and
display them as an image on a cathode ray tube in which the raster
scanning is synchronized with that of the microscope. The image
displayed is therefore a distribution map of the intensity of the signal
being emitted from the scanned area of the specimen.
SEM requires that the specimens should be conductive for the
electron beam to scan the surface and that the electrons have a path to
ground for conventional imaging. Non-conductive solid specimens
are generally coated with a layer of conductive material by low
vacuum sputter coating or high vacuum evaporation. This is done to
prevent the accumulation of static electric charge on the specimen
during electron irradiation. Non-conducting specimens may also be
imaged uncoated using specialized SEM instrumentation such as the
"Environmental SEM" (ESEM) or in field emission gun (FEG) SEM
operated at low voltage, high vacuum or at low vacuum, high voltage.
The SEM shows very detailed three dimensional images at much
high magnifications (up to ×300000) as compared to light microscope
(up to × 10000). But as the images are created without light waves,
they are black and white. The surface structure of polymer nano
composites, fracture surfaces, nano fibres, nanoparticles and
nanocoating can be imaged through SEM with great clarity. As very
high resolution images of the dimensions 1-5 nm can be obtained,
SEM is the most suitable process to study the nano fibres and nano
coatings on polymeric/textile substrate.
Figure 7: XRD patterns of the material obtained from (a) Synthesis 1 and
(b) Synthesis 2 [32].
Volume 3 • Issue 2 • 1000121
Electro spun nano fibres are extensively studied in biomedical,
environmental and other technical textile applications for their high
surface area. Electrospun nylon 6 nano fibres decorated with surface
bound silver nano particles used for anti bacterial air purifier can
be categorized using SEM (Figure 8a). In tissue engineering or cell
culture applications, the SEM image is the prime characterization
• Page 5 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
technique for scaffold construction, cell development and growth
(Figure 8b). SEM technique (Figure 8c) is used to observe the plied
CNT yarns in 3D braided structures.
The SEM technique can also be used to view dispersion of nano
particles such as carbon nano tubes, nano clays and hybrid POSS
nano fillers in the bulk and on the surface of nano composite fibres
and coatings on yarns and fabric samples.
SEM has been used for examination of the treated fabric surface
[2]. Figure 9a shows the nano scaled zinc oxide nano particles as seen
on polyester/cotton fabrics. The nano particles are well dispersed on
the fibre surface in both the cases, although some aggregated nano
particles are still visible [31].
The particle size plays a primary role in determining their
adhesion to the fibres. The largest particle agglomerates can get
easily removed from the fibre surface, while the smaller particles will
penetrate deeper and adhere strongly into the fibre matrix. The SEM
image in Figure 9b confirms that most of the large agglomerates are
removed from the textile surface after washing.
Characterization of Titanium Dioxide Nano Particles
Characterization of nano particles was done by three tests
such as X-ray Diffraction method and Fourier Transform infrared
spectroscopy (FTIR) and transmission of electron microscope [34].
The crystallinity was determined by XRD using a Bruker D8 advance
X ray diffractrometer equipped with a CuKa (λ=1.54 Ao) source (
applied voltage 40 kV, current 40 mV). About 0.5 gram of the dried
particles were deposited as a randomly oriented powder onto a
Plexiglas sample container, and the XRD patterns were recorded at
angles between 20o and 80o with a scan rate of 1.5o per min.
The crystalline domain diameters (D) were obtained from XRD
peaks according to the scherer’s equation:
D=
0.89λ
∆W Cosθ
Where λ is the wave length of the incident X0ray beam (1.54 Å for
CuKa), θ is the Bragg’s diffraction angle, ∆W is the width of the X-ray
pattern line at half peak height in radians. The chemical composition
of synthesized materials was checked by FTIR spectroscopy with a
Bio-Rad FTS-40 spectrometer. The shape and size of the nano particles
were obtained through TEM using a Philips EM201C apparatus
operating at 80 kv. The samples for TEM measurement were prepared
from much diluted dispersion of the particles in 2-propanol. Surface
area measurement was determined from BET on a coulter SA 3100
surface area analyzer, under N2 flow.
Characterization of Silica Nano Particles
Colloidal silica nano-particles are based on the hydrolysis
Figure 8: (a) Electrospun nylon 6 nano fibres with surface bound silver nano particles,
(b) Peptide nano fibre scaffold for tissue engineering, and
(c) SEM image of plied CNT yarn [1].
Figure 9: SEM images of ZnO nano particles obtained from synthesis 1 on (a) Polyester/Cotton before washing and (b) Cotton after washing [31].
Volume 3 • Issue 2 • 1000121
• Page 6 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
reaction of silicon alkoxide where the resulting particle size and
morphology depend strongly on the hydrolysis kinetics. In the
selected constituent concentrations, spherical, silica particles can be
obtained. The reaction time of this synthesis required 15 minutes.
The reaction continues until the solution is super-saturated [35]. To
investigate the possibility of tailoring the particle size and maybe the
particle size distribution, a kinetic study of the particle size evolution
as a function of reaction time was carried out. X-ray diffraction using
CuKα radiation (Philips X'pert) was used to determine the crystalline
structure of silica particles [36]. The silica particles were amorphous
according to XRD with peaks less than 2θ=10º conforming to the
JCPDS file (79-1711). This demonstrates that a high percentage of
these particles are amorphous, but a few of them are crystalline, as
the energy of amorphous silica is very close to that of crystalline silica
[37]. It has been reported that when one is interested in fine particles,
the water concentrations should be fixed at 0.2-3.2 M, also the molar
ratio of ammonia and TEOS should be the same. Silica nano-particles
were prepared taking into account these considerations. Figure 10
shows these particles and also the narrow size distribution of these
particles [38].
Vasconcelos and Campos [39] have considered the effect of
different molar ratios of reagents on the structure and morphology
of silica particles at room temperature. When the reaction was
conducted at 60ºC, silica nano-particles were also obtained. This
temperature was based upon a limitation of the boiling point of the
reagents.
Figures 10 and 11 show spherical and agglomerated silica nanoparticles, which were obtained using different molar ratios of reagents;
the molar ratio of the solvent is also important. With a lower molar
ratio of solvent (ethanol), agglomerated silica particles were obtained.
Park and Kim [40] have shown when a narrow size distortion is
required; a small molar ratio of ethanol should be employed.
The optimum conditions for synthesizing silica nano-particles
were considered to be with the same molar ratio of TEOS and
ammonia and a higher molar ratio of ethanol giving rise to smaller
silica nanoparticles with a broad distribution of particle sizes [41].
Stober and Fink [42] have shown the different solvent effects on the
size of particles. Using different solvents such as methanol, ethanol,
propanol, butanol and ethanol-glycerol, different structures were
obtained. From methanol and ethanol-glycerol, a stable sol could
be obtained, but when butanol and ethanol were used, precipitation
could be easily observed. Different experiments show that the
presence of glycerol during synthesis affects the precipitation [37].
Conclusion
The various nano materials used in textile finishing have been
characterized by the use of the Scanning Electron Microscope,
Infra Red Spectroscopy, Tunneling Electron Microscopy, and X-ray
Diffraction techniques. The nano particles observed were silver oxide,
titanium dioxide, and zinc oxide, which are considered to be very
important in the textile finishing process.
Figure 10: TEM image of silica nano particles [39].
The studies enable to determine the nano particle size, the surface
characteristics of the fabrics on which they have been applied. The
chemical composition of the nano materials has also been determined.
Figure 11: SEM micrographs of silica particles obtained from a molar ratio of water:TEOS:Ammonia:Ethanol [(a) 1:4:6:6 (b) 1:4:6:24].
Volume 3 • Issue 2 • 1000121
• Page 7 of 9 •
Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
Table 1: The scope of the various characterization techniques
S.No Types of Characterization techniques
Areas of applications
1
Scanning electron microscopy
Surface structures of nano particles, dispersion of nano particles, and surface of coated fibers and fabrics
2
Energy dispersive X-ray analysis
Composition or the amount of nanoparticles near and at the surface can be estimated, provided, they contain some
heavy metal ions. Suited for silver nano particles
3
Transmission electron microscopy
Enable to reveal the distribution of nano particles in polymer matrices of nano composite fibers, nanocoatings etc.
The extent of exfoliation, intercalation and orientation of nanoparticles can also be visualized.
4
High resolution transmission electron
microscopy
Enables study of nanoscale properties of nano materials. At such a high resolution, individual atoms and crystalline
defects can be imaged.
5
Atomic force microscope
Important in fundamental and practical research and development of versatile technical textiles for a variety of
applications. Also suggests possible ways to investigate the effect of plasma processing on the morphology of
textile surfaces
6
Scanning tunneling microscopy
A powerful tool in nanotechnology and nanoscience providing facilities for characterization and modification of a
variety of materials. It can move metal atoms and molecules on smooth surfaces with high precision.
7
Raman spectroscopy
Applicable for raman active textile fibers such as aramid and carbon
FTIR spectroscopy has enabled to identify the chemical composition
of synthesized nano particles. X-ray diffraction studies have helped in
determination of the crystallinity of nano particles. The Table 1 gives
the scope of the various characterization techniques.
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Volume 3 • Issue 2 • 1000121
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Citation: Gokarneshan N, Gopalakrishnan PP, Rachel DA (2015) Characterization Methods of Nano Textile Materials. J Fashion Technol Textile Eng 3:2.
doi:http://dx.doi.org/10.4172/2329-9568.1000121
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Author Affiliations
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NIFT TEA College of Knitwear Fashion, Tirupur 641 606, India
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