Fabrication of C6-Fluorocarbon-dendrimer based superhydrophobic cotton fabrics for multifunctional aspects


 C6-Fluorocarbon-dendrimer has been applied to the cotton knit fabric to develop oil-water repellent, oil-water separation, acid-resistant, self-cleaning, flame retardant, UV resistant, and antibacterial properties. The C6-Fluorocarbon (FC)-dendrimer-coated 100% cotton single jersey knitted fabric samples were prepared using the “pad-dry-cure” method. The 90 g/L and 100 g/L FC-dendrimer-treated cotton fabrics showed excellent water repellency and oil-water separation as well as good self-cleaning performance. However, air permeability and heat conductivity were reduced by 13%, 15%, and 40%, 54%, for 90 g/L and 100 g/L FC-dendrimer-treated cotton fabrics compared to untreated fabrics. The presence of FC-dendrimer in the treated fabric was confirmed by FTIR, SEM, EDS, and XRD analyses. SEM analysis was employed to study the morphology of deposited FC-dendrimer particles on the fabric surface. TGA and DTA evaluated thermal performance. The FC-dendrimer-treated fabric also showed acid resistance, self-cleaning performance, and UV resistant attribute. In addition, Bacterial population growth appears to be less on the FC-dendrimer-treated sample than on the untreated sample. Overall, the result suggests that FC-dendrimer can be a valuable ingredient in the manufacture of multifunctional products.


Introduction
The rapid growth in the use of protective textiles and their uses has created a serious need produced by the fabric's air permeability, waterespecially water Vapor-permeability, heat 120 permeability (Behera and Hari 2010). Wearing impermeable clothing can cause a 3 0 C rise in 121 temperature within ten minutes when a person is performing a physically moderate task and a 10 0 C 122 rise in temperature when performing physically demanding work (Day and Sturgeon 1986). 123 Generally, water-proof fabrics have lamination, high-density tight weaving and solid coating, all 124 of which block air and water vapor movement. As a result, the wearer feels discomfort, due to the 125 condensation of sweat inside the clothing. On the other hand, FC-dendrimer repellent finishes 126 overcome these problems by developing a permeable layer that allows water vapor, heat and air to 127 pass through the clothing. As Dendrimer macromolecule's ability to build up crystal structures in 128 nano range on the fabric surface with the benefit of not impairing the permeability the textile to 129 air and vapor. Then the wearer feels at ease. Such water-repellent fabrics can be used for various 130 types of protective garments against rain, snow and cold, active sportswear, etc (Krishnan 1991; groups (functional groups). The number of end groups increases exponentially with the number of 138 generations building up the dendrimer. 139 Fluorocarbon polymers are applied together with dendrimers, causing self-organisation 140 where the fluorocarbon chains are enriched on the surface and co-crystallize with the dendrimers. 141 Dendrimers are highly branched oligomers with non-polar chains forming a starbrush structure. reactions are also called photochemical reactions, which implies that light is absorbed in a 155 chemical substance (Appleyard, 2012). An outdoor jacket is usually being exposed to sunlight 156 and therefore this was an important test in order to evaluate the performance of the treated fabrics surface growth will only occur when the relative humidity is high. So, it is expected that the hydrophobic 169 property will be helpful for the inhibition of microbial growth. 170 Flame retardants are chemicals that are applied to materials to prevent the start or slow the growth  In view of all this information, the aim of the present work is to study the different 191 functional properties such as self-cleaning, oil-water separation, acid-resistant, antimicrobial    Gazipur. "RUCOSTAR EEE6" was used as a water-and oil-repellent chemical, which was C6-217 FC-dendrimer resin with polymeric hyperbranched dendrimers in a hydrocarbon matrix. Non-ionic 218 polysiloxane ("RUCOFIN HSF") was used as a softening agent and blocked polyisocyanate 219 ("RUCO LINK-RCX") was used as a cross-linking agent. All chemicals were purchased from 220 Spectra Dry-Chem (PVT.) Ltd., Germany. The dried samples were then mixed with KBr in the ratio of 1:100 using mortar and pestle.

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An FTIR spectrophotometer (Spectrum-100, Perkin Elmer, USA), with a scanning range of 400-238 4000 cm -1 was used to carry out the test. The crystallinity of the treated and untreated samples was evaluated by X-Ray diffraction 242 (XRD) analysis using X' Pert PRO diffractometer (PAN Analytical, Auckland, New Zealand). The 243 XRD was carried out using Cu-Kα radiation, of wavelength   0.15406 nm, as the X-ray source.

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The operating voltage and current were 40kV and 30mA, respectively, at room temperature. The 245 sample holder was placed in the X-ray goniometer and a 2 scanning range, over 5⁰-50, was 246 used.

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The 'd' spacing was evaluated according to Bragg's law: where, is 0.15406 nm is the X-ray wave length and d is the inter plane spacing. In this equation, K (= 0.9) is the Scherrer constant, the X-ray wave length is   0.15406 255 nm, is the Braggs diffraction angle, and β is the full width of the peak in the X-ray pattern line 256 at half peak-height in radians.

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The crystalline percentage (Cr %) of treated and untreated samples was calculated from the 258 XRD pattern, using the following equation Where: I002 is representing the crystalline region of the material, and Iam is representing the amorphous 262 region of the material in cellulose fibres.

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A scanning electron microscope was used to study the surface morphology of the cotton 266 fabric both before and after modification. SEM (Model-Phenom G2 pro, Netherland) was 267 performed to investigate the surface morphology at × 3000 magnification.

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The energy dispersive X-ray (EDS or EDX) represents the different elements composing      Acid resistance test 325 The extent to which the fabric was acid-resistant was tested by an acid drop test. 20μL of 326 98% sulfuric acid was dropped on the fabric with a micropipette. A digital camera then recorded    Where, K is the ability of the of the sample to conduct heat, m is the brass disc mass, s is 389 the specific heat of the disc material, d is the specimen thickness (in mm), is the cooling rate, 390 a is the area of the specimen cross-section, t1 is the highest temperature persisting over time and 391 t2 is the lowest temperature persisting over time.

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Water vapor permeability 397 The BS 7209 test (1990) was used to measure the water vapor permeability of the sample 398 using the following formula:

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Water vapor permeability = At In the above equation, M is mass loss (in grams), A is the sample's exposed area in m 2 and t is the Results and discussion 409 The manuscript has been organized so that the first confirmation tests, such as FTIR, XRD,    The untreated and FC-dendrimer-treated fabrics both showed three distinctive peaks, at the   No major difference is seen in the inter-plane spacing of untreated and FC-dendrimer-471 treated fabric as shown in Table 3. The X-ray diffraction shows that the characteristic peaks of 472 untreated and FC-dendrimer-treated fabric are almost the same. Thus, the cotton fibre cellulose 473 did not produce any remarkable changes after FC-dendrimer incorporation.         When the concentration of FC-dendrimer was 90 g/L and 100 g/L, the weight gain percentage was  are introduced onto the cotton surface, the surface will become more hydrophilic. As a result, a 609 water droplet will spread across the surface easily and the water contract angle will become 610 smaller. On the other hand, if hydrocarbons are introduced onto the surface, the surface will 611 become more hydrophobic and the water contract angle will become larger. Therefore, to measure 612 the water contact angle, a droplet of water is placed on the surface. The height and width of the 613 water's spread are then recorded to calculate the angle.

614
The 100 g/L and 90 g/L FC-dendrimer treated cotton fabric provided excellent water 615 repellence: its water contact angle measured between 154° and 144°, as shown in Fig. 8 (e, f). 60 616 g/L, 70 g/L and 80 g/L FC-dendrimer-treated cotton fabrics exhibited water contact angles of 124°,

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122° and 136°, respectively, as shown in Fig. 8 (b, c, d).  Fig. 9(c). The spherical shape of the water and oil droplet is shown in Fig. 9(c). Thus, FC 625 dendrimer-treated cotton fabrics are water and oil repellent.    The surface tension and density of n-heptene are 19.8 mN/m and 0.69 kg/dm 3 , respectively.

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The surface tension of n-heptane is less than that of the other organic oils which were used in the 661 oil repellence test, as shown in Table 1. N-heptane organic oil can easily wet 60 g/L, 70 g/L, and 662 80 g/L FC-dendrimer-treated fabric, but not 90 g/L and 100 g/L FC-dendrimer-treated fabric.

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Therefore, 90 g/L and 100 g/L FC-dendrimer-treated fabric showed an oil repellence rating of 8 664 (eight), according to the oil repellence test chart, as shown in Table 1. The high value of water 665 contact angle also indicated the high degree of oleophobicity. The water contact angle of 90 and 666 100g/L FC-dendrimer-treated fabrics are 154° and 144° as in Fig. 10 (e, f). 667 The surface tension and density of n-octane are 21.4 mN/m and 0.70 kg/dm 3 , respectively.   Self-cleaning coatings can be:

745
In super hydrophilic coatings, the surface is cleaned by the sheeting effect of water.

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Complex organic substances on the surface are broken down into carbon dioxide and water.  Fig. 13(a) shows that methylene blue dye powder spread widely on the untreated fabric 758 surface due to the capillary effects of cotton fibers. The coated cotton surface has extremely little 759 adhesion to methylene blue dye powder. However, dirt like methylene blue dye powder on the 760 superhydrophobic cotton surface was quickly and easily removed by water droplets. Thus, the 761 surface in Fig. 13(b-f) is clean and dry. Among the treated samples, 80 g/L, 90 g/L and 100 g/L 762 FC-treated samples showed better self-cleaning performance than did the 60 g/L and 70 g/L FC-763 treated samples.    Table 9 illustrates that UPF value gradually increased with increasing FC-dendrimer

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Clear microbial inhibition zones were not found for untreated or treated fabrics in Fig. 15 844 (a-f). However, bacterial population growth seems to be less on the FC-dendrimer-treated sample 845 in Fig. 11(b-f) than the untreated sample in Fig. 11(a). Among the treated samples, 100 g/L FC-846 dendrimer treated fabric (Fig. 11(f)) showed the lowest bacterial population growth.  Table 9 Thickness and GSM of treated and untreated fabric. image revealed that micro-roughness was developed on fluorocarbon-treated cotton ( Fig. 15(b-f)  where the expected results were that the treatment should be rubbed off to some extent. The spray 886 rating remained unchanged after 5,000 rub cycles, according to the results (Table 11). On the other 887 hand, water repellency was decreased a little bit after 10,000 rub cycle. Water spray rating of 60 888 g/L FC-dendrimer treated fabric was retained 4 according to ASTM D4966-98 (1989) method. 889 After a 10,000 rub cycle, 70 g/L FC-dendrimer treated fabric maintains a 4-5 spray rating. 80, 90, 890 100 g/L FC-dendrimer treated fabrics showed the best abrasion resistance.  Thermal conductivity is heat flow through a material. Table 12 illustrates that the least   The calculated values of 60 g/L, 70 g/L and 80 g/L FC-dendrimer-treated fabric are less 915 than the tabulated values as shown in Table 12 Table 13. The highest air permeability value existed 926 in 60 g/L and the air permeability of 90 g/L and 100 g/L treated fabrics were 13% and 15% lower 927 respectively, compared to that of untreated fabric. Among the FC-dendrimer-treated samples. As  The critical chi-square value is  2 at a 5% level of significance and the degree of freedom  Table 7. On the other hand, the calculated value for 80 g/L, 90 g/L and 100 g/L is 941 greater than the tabulated value, the null hypothesis is rejected as shown in Table 7. The 80 g/L, 942 90 g/L and 100 g/L FC-dendrimer-treated fabric observation did not achieve a sufficient value for 943 acceptance of the null hypothesis but the 60 g/L and 70 g/L FC-dendrimer-treated fabric 944 observation did. Thus, we conclude that 60 g/L and 70 g/L FC-dendrimer treatment will not 945 hamper air permeability or comfort of the fabric. But this will not hold true at higher levels of FC-946 dendrimer concentration.    The calculated values of 60 g/L and 70 g/L FC-dendrimer-treated fabrics are less than the 967 tabulated value, so the null hypothesis is accepted as shown in Table 15. On the other hand, the calculated values of 80 g/L, 90 g/L and 100 g/L FC-dendrimer-treated fabrics are greater than the 969 tabulated values, as a result, the null hypothesis is rejected. It may be concluded that 60 g/L and 970 70 g/L FC-dendrimer treatment will not hamper the water vapor permeability rate as well as In this study, spray rating did not change after five times machine wash. On the other hand, the 994 spray rating did not change after the 5000 rub cycle. Furthermore, 70, 80 and 100 g/L FC-995 dendrimer treated fabric still maintained their hydrophobicity even after the 10,000 rub cycle. 996 Therefore, it can be said that self-cleaning, oil-water separation, hydrophobic, antibacterial, UV  Fluorocarbon polymer on bre surface. Where m=6-10, X and Y are co-polymers mainly stearylacrylates, R= H or CH3 (polyacrylic or polymethacrylic acid esters), and A is the re surface.

Figure 2
A dendrimer structure synthesized from three distearyl-amines or amides and a tri-functional isocyanate X (N=C=O).       Water-oil repellent properties of (a) & (b) Untreated fabric and (c) 100 g/L FC-dendrimer treated fabric.

Figure 10
Oil repellency rating of the FC-dendrimer treated sample.

Figure 11
Schematic diagram of oil-water separation process.