Synthesis and Reactivity in Inorganic, Metal-Organic

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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lsrt20

Enhancement of UV Property on Cotton Fabric by TiO2 Nanorods a

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K. Sasipriya , P. Manivasakan , R. Yuvakkumar , N. R. Dhineshbabu , P. Prabu & V. Rajendran

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Centre for Nanoscience and Technology , K. S. Rangasamy College of Technology , Tiruchengode , Tamil Nadu , India Accepted author version posted online: 24 Aug 2013.Published online: 16 Dec 2013.

To cite this article: K. Sasipriya , P. Manivasakan , R. Yuvakkumar , N. R. Dhineshbabu , P. Prabu & V. Rajendran (2014) Enhancement of UV Property on Cotton Fabric by TiO2 Nanorods, Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 44:5, 748-758, DOI: 10.1080/15533174.2013.790430 To link to this article: http://dx.doi.org/10.1080/15533174.2013.790430

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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 44:748–758, 2014 C Taylor & Francis Group, LLC Copyright ISSN: 1553-3174 print / 1553-3182 online DOI: 10.1080/15533174.2013.790430

Enhancement of UV Property on Cotton Fabric by TiO2 Nanorods K. Sasipriya, P. Manivasakan, R. Yuvakkumar, N. R. Dhineshbabu, P. Prabu, and V. Rajendran

Downloaded by [National Taipei University of Technology] at 05:07 18 December 2013

Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tiruchengode, Tamil Nadu, India

TiO2 nanoparticles were prepared at low temperature using TiCl3 . Rutile phase TiO2 agglomerated nanoparticles showed a rod-like morphology. Diameter of TiO2 nanorods was controlled by varying acidic catalyst and calcination temperature. At 1073 and 1273 K, nanorod was deformed to elliptical like morphology with unagglomerated particles. TiO2 nanoparticles were padded on surface of cotton fabric using silica sol and characterized comprehensively. The effect of ultraviolet protection on TiO2 nanorods coated cotton fabric was determined. High ultraviolet protection factor indicates that the TiO2 nanoparticles coated on cotton fabrics show good ultraviolet protection efficiency. Keywords

dip-pad-dry-cure process, functional fabrics, TiO2 nanorods, TiO2 /SiO2 nanocomposites, UV protection

INTRODUCTION Textile industries are focused to implement the nanotechnology on fabrics. Organic and inorganic nanoparticles are coated on fabric material to improve the functional properties. Titania nanoparticles widely used in many field especially textile sector because it has nontoxicity and photocatalytic activity.[1,2] Titania, as one of the most important oxides, is of great interest in view of its high performance applications ranging from photocatalysis to sensor devices.[3,4] This is mainly because of its unique features such as long thermal stability, inexpensiveness and superior photo reactivity.[5,6] In addition, because of its technological importance it finds applications in different fields such as optical coating, pigment, air purification, antifogging, antibacterial,[7] self-cleaning, and good ultraviolet (UV) protective power under UV exposure conditions.[8] Titania, a demanding material, exists naturally in three different crystal phases,

Received 17 July 2012; accepted 23 March 2013. The authors acknowledge financial support by the Defence Research and Development Organization (ERIP/ER/0604354/M/01/991), New Delhi, to carry out this research project. Address correspondence to V. Rajendran, Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tiruchengode 637 215, Tamil Nadu, India. E-mail: [email protected]

namely anatase, brookite, and rutile, in which anatase and rutile are most significant because of their high photocatalytic activity.[5,6,9] Even though the anatase phase has been accepted as a more efficient photocatalyst than rutile, researchers have shown that rutile TiO2 possesses excellent photocatalytic properties because of the strong UV ray absorption rate in the near UV light region.[10–12] Moreover, rutile is known to be the most stable phase at all temperatures up to the melting point,[13] whereas the other two phases (anatase and brookite) are metastable at all temperatures.[8,14,15] Conversely, rutile TiO2 shows excellent physical and chemical properties because of its high dielectric constant, refractive index, and chemical inertness.[4,13,14] Different approaches are being actively used to produce nano-sized rutile TiO2 powder with controlled morphological characteristics by the hydrolysis of different titanium salts such as alkoxides Ti(OR)4 and TiCl4 .[4,10,13,16] Only a few attempts have been reported for the synthesis of nanocrystalline pure rutile TiO2 at low temperatures by hydrolysis of TiCl3 [17,18] as an affordable precursor. However, the synthesis of TiO2 nanoparticles is still challenging in terms of high surface area, particle size, and morphology to enhance the efficiency of UV protection, photocatalytic and antibacterial activity for applications such as cosmetics, catalysts, paints,[9] and so on. Nowadays, there is a great demand to modify the surface of textile materials to enhance their functional properties, such as antibacterial properties, UV protection, water repellence, hydrophobicity, crease resistance, and smoothness, which exceed those traditional textiles in medical, military, and other specialty commercial applications.[19] The application of nanostructured materials to fabrics enhances the performance and properties of the textile materials. The modification of cotton fabrics by using TiO2 nanosol facilitates use as an excellent UV ray protection in the region of UV-B.[20] Similarly, photoactive fibers are produced by depositing TiO2 nanoparticles on cellulose fibres by using the sol-gel method at low temperature. A bifunctional cotton textile with superhydrophobic and UV shielding properties has been developed by TiO2 coating.[21,22] Self-cleaning properties of textiles[23] were developed and reported by coating TiO2 /SiO2 nanocomposites on cotton fabrics. Recently, an attempt has been made to functionalization of ZnO and TiO2

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hydrochloric acid solution (35%; Merck). Desized, scoured, and bleached 100% plain cotton fabrics were used in this study. The mass of the woven fabric was 132.48 g m–2, weft yarn count 107s and warp yarn count 98s, and picks/inch 82, ends/inch 112.

FIG. 1. XRD patterns of TiO2 nanoparticles obtained at different proportion of acidic catalyst (T-5/2, T-5/3, and T-5/4).

nanoparticles on cotton fabrics for developing the ultraviolet shielding properties of textiles.[24] Therefore, it is of interest to explore TiO2 as a coating material for textile fabrics because of its unsurpassed multifunctional properties. According to the previous introduction, the synthesis, characterization, and fabrication of TiO2 nanorods embedded silicate network modified cotton fabrics has been found to be scant. The present goal was intended to characterize the formation of TiO2 nanorods with different percentages of acid catalyst at different calcination temperatures. Moreover, an attempt has been made to develop functional textiles with enhanced properties using TiO2 nanorods embedded silicate network. The TiO2 nanorods were characterized by various techniques such as Xray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR). It has been found that variation in the concentration of the acidic catalyst and sintering temperature is critical for the morphology and particle size of the TiO2 nanoparticles. Subsequently, TiO2 nanorods were coated on the surface of cotton fabrics using dip-pad-dry-cure process by dispersing TiO2 nanorods on the silica sol. SEM, XRD, attenuated total reflectance Fourier transform infrared spectroscopy (ATRFTIR), and energy-dispersive X-ray analysis (EDAX) are used to characterize the nano TiO2 coating and its effect on cotton fabrics. In this work, it has been found that the resulting material shows good UV protection with an increase in mechanical properties. EXPERIMENTAL Materials All the reagents used were of analytical grade without further purification. The chemicals used were TiCl3 (15%; Loba) and

Synthesis of Rutile TiO2 Nanoparticles In a typical synthesis of rutile TiO2 nanoparticles, 5% TiCl3 was used as a starting precursor and HCl as a hydrolysis catalyst to control the speed of hydrolysis of the source of titanium. The percentage ratio of the catalyst that was used varied from 2% to 4%. A mixture of TiCl3 and distilled water was stirred for a sufficient time. The diluted HCl was slowly added to the TiCl3 solution under magnetic stirring. Additions of 1 mM cetyl trimethylammonium bromide (CTAB) were made to the resulting solution after the mixture was stirred sufficiently for 1 h. Hydrolysis was conducted at 323 K with vigorous stirring for 24 h. After stirring for a sufficient time, the violet solution turned into white precipitate and was maintained at room temperature overnight. Then, the white precipitate was filtered and dried at 353 K for 24 h, followed by calcination at 473 K for 3 h. Samples synthesized as a function of TiCl3 and HCl in the percentage ratios of 5:2, 5:3, and 5:4 are termed hereafter as T-5/2, T-5/3, and T-5/4, respectively. Moreover, the sample (T-5/3) was calcinated at different temperatures, 673, 873, 1073, and 1273 K, respectively, for 3 h to explore the effects of temperature on size and morphological features of nano TiO2 particles. Coating of TiO2 Nanoparticles on Cotton Fabric Titania nanoparticles (T-5/3) with different percentages respectively 2%, 4%, 6%, 8%, and 10% (w/v; termed hereafter as TS-2, TS-4, TS-6, TS-8, and TS-10) were incorporated into silica sol to prepare coating solution based on the over weight of the fabrics (owf). The solution containing 2 mL of tetraethyl orthosilicate (99%; Merck) with 25 mL of ethanol was hydrolyzed with the addition of 5 mL of water and was magnetically stirred for 1 h at room temperature to get a clear solution. Then a solution of aqueous ammonia (2.5 M) was added slowly. After being magnetically stirred up for 3 h at room temperature, a white solution of silica sol was obtained. Two percentages of prepared TiO2 nanoparticles (T-5/3) were dispersed with ethanol in an ultrasonic bath for 10 min and then added to SiO2 sol to form nano TiO2 enabled silica sol (2% w/v, TS-2). A 15 × 15 cm cotton fabric was dipped into the nano TiO2 powder dispersed silica sol for 30 min and was then treated by a conventional pad-dry-cure method. The padded cotton fabric was dried at 373 K for 5 min in a preheated oven and ultimately cured at 413 K for 3 min in a curing oven to ensure the adsorption of TiO2 nanoparticles on cotton fabrics. The above process was repeated for the different percentages (TS-4, TS-6, TS-8, and TS-10) of the nano TiO2 coating on cotton fabric samples.


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FIG. 2.

XRD patterns of TiO2 nanoparticles after calcination at different temperatures.

Characterization Techniques XRD analysis (X’Pert Pro, PANalytical, the Netherlands) was performed to study the crystal structures, crystallite sizes and phase formations of the prepared samples. The crystallite size was evaluated from the observed X-ray pattern based on Scherrer’s formula.[25] Morphology, shape, size, distribution of TiO2 nanoparticles, and their nature of adherence on cotton fabrics were studied by SEM (JEOL, Japan) and TEM techniques (CM200, Philips, USA). The samples were subjected to EDX to verify the elemental composition on the surface of the fabrics. FTIR spectra were recorded for the TiO2 nanopowders by forming a TiO2 pellet with KBr in the region of 4000400 cm−1 (Spectrum100, Perkin-Elmer, USA). FTIR spectra of the TiO2 coated fabrics were also characterized using the ATR-FTIR method (Spectrum100, ATR, Perkin-Elmer). The UV-visible transmittance spectrums for the coated and uncoated fabrics were recorded using UV-visible-NIR Spectrophotometer (Carry 5000, Varian, USA). The UV protection factor (UPF) for

the cotton fabric was calculated from the transmittance value that was observed according to the Australian/New Zealand standard AS/NZS4399 (1996). RESULTS AND DISCUSSION Structural Characterization, Morphology, and EDS Analysis of TiO2 Nanoparticles The XRD patterns of the as-synthesized sample with an increase in the acid catalyst (T-5/2, T-5/3 and T-5/4) are shown in Figure 1. The figure represents the diffraction pattern for the sample with an increase in the acidic catalyst (2–4% of HCl), which is attributed to the tetragonal symmetry of the rutile TiO2 phase. The absence of the other diffraction line shows that the other polymorphs of TiO2 such as anatase or brookite are absent.[9,26] The strong peaks observed at (110), (101), and (211) indicates that the material is oriented preferentially.[3] According to Scherrer’s formula for the rutile (110) diffraction peaks,



the average crystallite sizes of the samples were found to be 9, 8, and 7 nm for samples T-5/2, T-5/3, and T-5/4, respectively. These results indicate that the crystal sizes of the resulting rutile nanorods decrease with an increase in the percentage of HCl from 2 to 4. It can be seen from Figure 1 that the optimum reaction (T-5/2, T-5/3, and T-5/4) occurred with 5% of TiCl3 , 2%, 3%, and 4% of HCl, which results in the formation of smaller nanoparticles. It is interesting to note that the amount of acid catalyst has significant effects on the preparation of TiO2 nanoparticles. The samples obtained by calcination at different temperatures as shown in Figure 2 were also assigned to the rutile phase (JCPDS File No.: 21-1276) of TiO2 . The full width half maximum (FWHM) of (110) peak decreases as the calcination temperature increases from 673 to 1273 K with an increment of 200 K for four segments (673, 873, 1073, and 1273 K). It is suggesting that the crystallite size and crystallinity of TiO2 grains increase gradually with an increase in the calcination temperature, which is in good agreement with the expected results.[3,27] The presence of the functional chemical group and the formation of TiO2 are represented in a typical FTIR spectrum. The FT-IR spectra of TiO2 nanoparticles with increase in acid catalyst are shown in Figure 3. The broad bands appearing in the region between 400 and 1000 cm–1 are the characteristic peaks of the Ti-O stretching mode. Furthermore, the broad peak around 3400 cm–1 and the band at 1618 cm–1 correspond to the stretching and bending modes of the O-H group of absorbed water molecules, the observed peaks 1049 and 1050 cm–1 correspond to carboxylate bonds and most probably, as the Ti-OH surface group.[28–31] The wave band that is observed at 650 cm–1 corresponding to the Ti-O stretching vibrations which shows a shift in the T-5/3 spectra and illustrates the percentage of the acid catalyst also shows a significant effect on the formation of TiO2 .[32] Figure 4 shows the FT-IR spectra of T-5/3 samples that were calcinated at different temperatures respectively 673, 873, 1073, and 1273 K for 3 h. Band intensity at 3400 and 1619 cm–1 corresponds to the characteristics of the associated surface adsorbed water and the hydroxyl groups.[30,31] The intensity of the band was gradually reduced with an increase in the calcination temperature. The broad bands over the range of 1000-400 cm−1 related to the bending and stretching modes of Ti-O-Ti and are characteristic of well ordered TiO6 octahedrons which confirm the presence of the nanocrystalline rutile TiO2 phase.[33] The FTIR spectra of the calcinated TiO2 nanoparticles show the strong intensity of the Ti-O band which predicts the effective growth of TiO2 crystals compared with the synthesized samples. The surface morphology and SEM microstructure of the assynthesized TiO2 particles with a variation in the acidic catalyst and the calcinated samples (673, 873, 1073, and 1273 K) are shown respectively in Figures 5 and 6. Figure 5 shows a dense agglomerated microstructure that shows several ultra small particles of few nanometers in size. Some of the particles might

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FIG. 3. FTIR spectra of TiO2 powders obtained at different proportion of acidic catalyst (T-5/2, T-5/3, and T-5/4).

be fused together to generate larger aggregates.[26] It has been noted from Figure 5 that the variation in the percentage of the HCl catalyst is important which induces the formation of rodlike morphology and regulates the shape and size of the TiO2 particles. Rod-like morphology with a variation in grain size has been observed in the calcinated samples as shown in Figure 6. At the temperatures 1073 and 1273 K, the morphology of the particles changed from a rod-like to an elliptical structure with nearly unagglomerated particles as presented in Figure 6. The above result indicates that the grain growth increases at higher temperature. Figure 5 reveals that the sample consists of 58.35 wt% of Ti and 41.65 wt% of O without the presence of any residual carbon. The size, morphology, and dispersion of the calcinated samples were analyzed by TEM measurements. Figure 7 shows that the representative TEM micrographs of the TiO2 sample which reveals that the samples consists of rod-like morphology with a mean length of 227 nm and a mean diameter of 104 nm. It can be seen from Figure 7 that the particles are distributed almost uniformly and deformed into an elliptical morphology after calcination of the sample at 1073 and 1273 K. It is interesting to note that the length and diameter of the rutile nanorods increased with the increase in the calcination temperature was observed from Figure 7. The aspect ratio increases as a function of an increase in the calcination temperature and gradually reduces in the calcination temperature range of 1073–1273 K because of grain growth. These results suggested that the shape and the aspect ratio of the rutile rod can be controlled by varying


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FIG. 4.

FTIR spectra of TiO2 nanoparticles after calcination at different temperatures.

the calcination temperature. It is notable that the size estimated from TEM studies is comparable to values obtained from SEM studies as represented in Figure 6. Effect of Nano TiO2 Coating on Cotton Fabrics Morphology and Compositional Analysis SEM analyses were carried out on all the nano coated samples to examine the nano TiO2 coating on the surface of the cotton fabrics. Figure 8 illustrates the SEM micrographs of uncoated and the different percentage of nano TiO2 incorporated silica sol coated cotton fabrics. The different percentage (owf) of nano TiO2 coated cotton fabrics showed significant changes in the fabric surface, which consisted of a few aggregates. It showed the presence of TiO2 nano particles on the fabric surface, which were surrounded by the spherical morphology of the silica particles. Furthermore, the surface morphology of the nano TiO2 coated cotton fabric samples after washing was analyzed using SEM analysis as shown in Figure 9. It can be seen from SEM analysis that the nano TiO2 particles are well adhered to the surface of the fabrics after washing, because of the linkage

between the hydroxyl groups of TiO2 and the SiO2 network with the surface hydroxyl groups on cellulose molecules.[20,34,35] Figure 9 shows the EDAX spectrum of pure cotton fabrics and Figure 9 nano TiO2 incorporated silica sol coated cotton fabrics. EDAX results confirm that the cotton fabrics consist only of titanium, silicon, and oxygen in addition to the presence of residual carbon. The element of silicon exists from the coating medium (silica sol) used for the dispersion of TiO2 . Table 1 lists the percentage composition of individual element present on the cotton fabrics after the coating of different percentage (owf) of nano TiO2 incorporated silicate. Thus, the presence of nano TiO2 on the cotton fabrics has been increased linearly with increasing the addition of percentage of nano TiO2 in silica sol as a constant coating medium. Figure 9 shows the stability of nano TiO2 particles on the surface of the cotton fabrics. It is noteworthy that a significant amount of TiO2 and silica where present on the cotton fabrics after washing. Structural Analysis Figure 10 shows the XRD analysis of the cotton fabric before and after coating with TiO2 nanoparticles incorporated silica



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FIG. 5. SEM images of TiO2 nanoparticles obtained at different proportion of acidic catalyst: (a) T-5/2, (b) T-5/3, (c) T-5/4, and (d) the typical EDS spectrum of T-5/3 sample. (color figure availabe online).

FIG. 6. SEM images of synthesized TiO2 nanoparticles calcinated at different temperatures: (a) 673 K, (b) 873 K, (c) 1073 K, and (d) 1273 K for 3 h. (color figure availabe online).


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FIG. 7. TEM images of synthesized TiO2 nanoparticles calcinated at different temperatures: (a) 473 K, (b) 673 K, (c) 873 K, (d) 1073 K, (e) 1273 K, and (f) variation of average particle size with the calcination temperature.

sol. The typical XRD patterns for pure cotton fabric showing the diffraction peaks at 14.92◦ , 16.59◦ , 22.82◦ , and 34.34◦ are in accordance with the JCPDS file No.3-0226.[36] In addition, diffraction peaks at 27.87◦ , 36.44◦ , 40.88◦ , 54.66◦ , and 70.74◦ shows that TiO2 nanoparticles incorporated silica sol coated fabrics are closely associated with the rutile phase of TiO2 [4,13] with the additional characteristic peaks of cellulose.[36] Hence, it is clear that nano TiO2 particles are coated on the cotton fabrics using a stable silica sol. Figure 11 presents the ATR-FTIR absorbance spectra of uncoated and TiO2 nanoparticles incorporated silica sol coated cotton fabrics. The spectra assigned for the uncoated sample show the characteristic peaks of cotton (cellulose) fabrics.[37,38] The increase in intense peaks at 1058 cm–1 has been observed after coating with TiO2 nanoparticles dispersed silica sol. Such an increase in peak value may be assigned to the Si-C stretching character of silica with the cellulose bands. The TiO2 nanoparticles dispersed silica sol coated

fabrics showed an additional peak at 958 cm–1, belonging to the Ti-O-Si vibration band which confirms the modification of cotton fabrics using TiO2 nanoparticles in the presence of silica sol.[23] The previous studies conclude that the coating of TiO2 nanoparticles dispersed silica sol on cotton fabrics forms hydrogen bonding with the hydroxyl groups of cellulose molecules of fabrics as reported elsewhere.[20,39] UV-vis Measurements The protective properties of nano TiO2 coated textile fabrics against UV radiation have been analyzed and shown in Figure 12. The transmittance spectra of the cotton fabrics coated with a different percentage of nano TiO2 incorporated silica hybrid particles were determined by UV-Vis spectrophotometer. The UV protection ability of nano TiO2 coated cotton fabrics has been explored using the UV-Vis transmittance spectra of coated and uncoated cotton fabrics. The decrease in the

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FIG. 8. SEM images of uncoated and different weight percentage of TiO2 nanoparticles coated cotton fabrics: (a) uncoated fabric, (b) TS-2, (c) TS-4, (d) TS-6, (e) TS-8, and (f) TS-10.

percentage of transmittance of UV radiation is noticed for coated cotton fabrics, which points out the UV shielding effect of TiO2 nanoparticles. Moreover, it is observed that the UV transmittance in the range of 315–400 nm (UV-A region) was decreased with increasing the percentage of nano TiO2 in coatings (TS-2, TS-4, TS-6, TS-8, and TS-10). This confirms the quantitative UV shielding property of TiO2 nanoparticles incorporated silica sol coated cotton fabrics. The spectra of TS-2, TS-4, and TS6 samples are gradually reduces the transmittance intensity of UV radiation which is considered as good UV blocking property. Samples TS-8 and TS-10 (8% and 10% of nano TiO2 in coatings, respectively) shows a slight increase in transmittance intensity when compared to the samples TS-6 and TS-4. It can be seen from Figure 12 that the samples TS-4 and TS-6 shows better UV protection property (decreased UV transmittance intensity) than TS-8 and TS-10. This may that be the higher concentration of nano TiO2 induces flocculation of the particles in coatings, which leads to higher particles size and transmits higher UV in-

tensity rather than absorption. Ultimately, the 6% of nano TiO2 incorporated silicate (TS-6) coating shows the peculiar performance as efficient UV absorbers, which can be optimized and efficiently transferred to cotton fabrics for effective UV shielding. TABLE 1 Elemental compositions of nano TiO2 coated cotton fabric imparted using silica sol Sample TS-2 TS-4 TS-6 TS-8 TS-10

C

O

Ti

Si

TiO2

SiO2

39.28 30.51 32.95 18.3 19.14

54.7 55.44 57.08 56.39 55.97

1.44 7.89 5.9 19.56 16.74

4.58 6.16 4.06 5.74 8.15

20.51 49.65 52.61 72.04 61.17

79.49 50.35 47.39 27.96 38.83


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FIG. 9. EDAX spectrum (a) uncoated cotton fabrics, (b) TiO2 nanoparticles coated cotton fabrics, (c) TiO2 nanoparticles coated cotton fabrics after washing, and (d) SEM images of TiO2 nanoparticles coated fabric after washing. (color figure availabe online).

FIG. 10. XRD spectra obtained from uncoated cotton fabric and TiO2 nanoparticles coated cotton fabric. FIG. 11. ATR-FTIR spectra of uncoated cotton fabric and TiO2 nanoparticles coated cotton fabric.


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ing property of nano TiO2 incorporated silicate coating which shows that the nano TiO2 particles adhere well to the surface of cotton fabrics.[1,39] As discussed in UV transmittance spectra, the UPF value also dramatically reduced for the TS-8 sample with a slight increment in the TS-10 sample. This means that at a higher concentration of nano TiO2 particles, an abrupt agglomeration takes place because of its higher surface energy.[19] Hence, it can deduce that the prepared nano TiO2 incorporated silicate coated cotton fabrics shows a significant UV shielding property.

FIG. 12. UV–vis spectra of uncoated and nano TiO2 coated fabric.

Generally, a UPF value of 40–50+ indicates excellent protection yielded by clothing against damage to the human skin from UV radiation. The UV absorption study of the coated fabrics showed a high UPF rating of 50+, which belongs to the excellent protection classification according to the Australian/New Zealand standard AS/NZS4399 (1996),[21] compared with UPF rating for uncoated fabric.[40] The calculated UPF of the uncoated cotton fabric is 6.8, which increased gradually to 45.4, 93.5, and 160.4 for TS-2, TS-4, and TS-6 samples, respectively. UPF values of uncoated and nanoTiO2 coated fabrics are represented in Figure 13. The increased UPF value of coated cotton fabrics confirms the remarkable UV shield-

CONCLUSIONS In summary, a simple soft chemical process has been developed for production of TiO2 nanoparticles through acid (HCl) catalyzed hydrolysis by using TiCl3 as a precursor and CTAB as a stabilizer. Powder characterization studies reveal that the produced TiO2 nanoparticles consist of rutile crystalline phase with rod-like morphology. The obtained TiO2 nanoparticles have been successfully embedded into silica sol under sonochemical reactor. Nano TiO2 embedded hybrid silica sol were coated on cotton fabrics using conventional pad-dry-cure method. It can be revealed that the size and morphology of the TiO2 nanoparticles were controlled by controlling the percentage of catalyst and calcination temperature. Significant changes on the surface morphology of cotton fabrics were shown in SEM for different percentages of TiO2 nanoparticles coated cotton fabrics. The coated cotton fabrics have good stability after industrial washing, which was confirmed by SEM and EDS data of the washed fabrics. The samples TS-2, TS-4, and TS-6, showed better UV protection property in the UV-A region. Hence, TiO2 nanoparticles coated cotton fabrics show better UV protection with a UPF value of 50+. The developed nano coating technology can be viable and easily transferred to textile industry for generating cotton fabrics with UV shielding property. REFERENCES

FIG. 13. UPF values of uncoated and nano TiO2 coated fabric. (color figure availabe online).

1. Daoud, W.A.; Xin, J.H. Low temperature sol-gel processed photo-catalytic titania coating. J. Sol-Gel. Sci. Technol. 2004, 29, 25–29. 2. Fujishima, A.; Honda, K. Electrochemical photolysis of water at a semiconductor electrode. Nature 1972, 238, 37–38. 3. Coronado, D.R.; Gattorno, G.R.; Pesqueira, M.E.E.; Cab, C.; Coss, R.D.; Oskam, G. Phase-pure TiO2 nanoparticles: anatase, brookite and rutile. Nanotechnology 2008, 19, 145605–14. 4. Tahir, M.N.; Theato, P.; Oberle, P.; Melnyk, G.; Faiss, S.; Kolb, U.; Janshoff, A.; Stepputat, M.; Tremel, W. Facile synthesis and characterization of functionalized monocrystalline rutile TiO2 nanorods. Langmuir 2006, 22, 5209–5212. 5. Wang, Y.; Zhang, L.; Deng, K.; Chen, X.; Zou, Z. Low temperature synthesis and photocatalytic activity of rutile TiO2 nanorod superstructures. J. Phys. Chem. Comp. 2007, 11, 12709–12714. 6. Zhang, D.; Qi, L.; Ma, J.; Cheng, H. Formation of crystalline nanosized titania in reverse micelles at room temperature. J, Mater, Chem. 2002, 12, 3677–3680. 7. Machida, M.; Norimoto, K.; Kimura, T. Antibacterial activity of photocatalytic titanium dioxide thin films with photodeposited silver on the surface of sanitary Ware. J. Am. Ceram. Soc. 2005, 88, 95–100.


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