Smart Cotton Functionalized With Self-Implanted Palladium Nanopanicles: Full Ultraviolet Shielding Potency


 Unique technique is currently demonstrated for preparation of ultraviolet protective cotton fabrics with full shielding effect, via self-implantation of palladium nanopanciles. Palladium (Pd) nanopanciles were in-situ immobilized within native & cationized cotton using two different concentrations of palladium precursor (20 & 60 mM) under strong acidic (pH 2) and basic (pH 11.5) media. Cationization (50% and 100%) of cotton fabrics was performed in order to increase the accessibility of fabric for controllable implantation of palladium nanopanciles. Size distribution of palladium nanopanciles in supernatant solution was estimated via Transmission electron microscopy to be 3.2 nm. The estimated data showed that the sample prepared with the highest cationization percent and highest concentration of palladium precursor in strong alkaline medium exhibited the highest yellowness index, color strength and excellent ultraviolet shielding effects. The yellowness index was significantly increased from 15.67 for cationized cotton to 74.99 for the sample prepared with the highest cationization percent and highest concentration of Pd+2 in alkaline medium (Pd-CC (100)4). Tensile strength was insignificantly decreased from 93.2 MPa for cationized cotton to 84.5 MPa for Pd-CC (100)4. Ultraviolet shielding effect was superiorly enhanced with implantation of palladium nanopanciles. The UV protection factor (UPF) was also excellency increased from 1.3 (insufficient) for native cotton to 256.6 (excellent) for Pd-CC (100)4.


Introduction
Increment for the consideration over damaging resulted from the exposure to microbial organisms, chemical reagents, insecticides, ultraviolet irradiation and pollutants in the last decade, has heightened the requirement for protective clothing materials. Garments today is required to be waterproo ng, ame resistant, self-cleaning, pest repellent and microbicidal to protect human body from the infections, ultraviolet irradiation, chemical and biological reagents, be warmer in cold weather and comfortable in summer. Conventional methodologies of nishing application, such as pad-dry-cure or coating that are recently being applied to make the fabrics acquired the microbicidal, ultraviolet shielding, self-cleaning and re-retardant nishing reagents, are usually combined with increment in ber thickness, loss of smoothness and drape, lowering the washing fastness, poor of mechanical properties and most importantly reduced the comfortability to the wearers ( Mostly, the protective clothes were actually ascribed to impair user potentiality. Moreover, there are vital safety issues correlating to the application as well as the disposal of chemical reagents used in contemporary nishing. Therefore, the researchers considered with the eld of textile industry were continued to look for alternative nishing reagents and technologies that must be environment friendly, with high fastness, costless and do not disadvantageously affect the comfortability of clothes while providing e ciency and optimum protection (Hassabo et  For acquirement of any additional functions to the textile materials, numerous reports were considered with the exploitation of some organic reagents, like triclosan for antibacterial potency, benzophenones for ultraviolet shielding, dimethylol dihydroxy ethylene urea for anti-crease performance, uorocarbons for lipophilic characters, long-chain hydrocarbons and polydimethylsiloxanes for exibility and softening (Almeida 2006;Hewson 1994). Butane tetra-carboxylic acid, citric acid and maleic acid (Yang et al. 1998;Welch 1988;Yang et al. 2010) were also exfoliated for acquiring cotton fabrics with anti-crease action.  Rikkinen et al. 2011). Moreover, palladium nanostructures were found to be more e cient in removal of dyes from the aqueous media via the heterogenous catalysis than many typically applied methodologies, like ltration, biological treatment, chemical precipitation, adsorption and techniques. According to our knowledge, no researching studies were considered with exploitation of palladium nanostructures in textile functionalization.
Herein, a novel/investigative approach for preparation of excellent ultraviolet protective cotton fabric is uniquely proposed via self-implantation of palladium nanopanciles. Whereas, for the rst time, the immobilized palladium nanopanciles were functionalized in acquirement of the treated fabrics excellent ultraviolet shielding potency. The particle size of the dispersed palladium nanopanciles in supernatant solution was estimated from transmission electron microscopic images. Regulative implantation of palladium nanopanciles was proceeded via immobilization within the polymeric matrix of both native and cationized cotton fabrics. Afterward, the modi ed fabrics were characterized via infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), colorimetric measurements (color coordinates and color strength), mechanical properties (tensile strength and elongation percentage), and UV-protective action (transmittance percent, ultraviolet protection factor UPF and ultraviolet protection rating).

Materials and chemicals
Palladium chloride (PdCl 2 , 99%, from Sigma-Aldrich -USA), Sodium hydroxide (99%, from Merck, Darmstadt-Germany), acetic acid and sodium carbonate were of laboratory grade chemicals. 3-Chloro-2hydroxypropyl trimethyl ammonium chloride (69%) of technical grade chemicals (known as  was purchased under the commercial name CR-2000 from Aldrich. All the chemicals were used as supplied without any further puri cation. Mill de-sized, scoured and bleached cotton fabric, plain weave, supplied by El-Nasr Company for spinning weaving and Dyeing El-Mahallah El-Kubra, Egypt. The fabric was further puri ed in the laboratory by washing at 100 o C for 60 min using a solution containing 2 g/L, Na 2 CO 3 and 1 g/L, non-ionic surfactant. The fabric was then washed several times with boiling water then with cold water and nally dried at ambient conditions.

Cationization of cotton fabrics
Chemical modi cation of the cotton gauze through cationization was carried out as per the pad-dry-cure method (Hashem et al. 2009;Hashem et al. 2005). The experimental procedures adopted were as follows: 3-Chloro-2-hydroxypropyl trimethyl ammonium chloride (Quat-188) was mixed with sodium hydroxide solution at a NaOH/Quat-188 molar ratio of 2:1. The cotton gauze was padded in this mixture in two dips and two nips, and then squeezed to a wet pick-up of about 100%. The cotton gauze was dried at 40 o C for 10 min and cured at 120 o C for 3 min. Thus, treated cotton gauze was washed with cold water and 1% acetic acid, followed by several washing cycles and nally dried under the normal laboratory conditions.

Self-implantation of palladium Nanopanicles
The palladium Nanopanicles were self-implanted in to the native and cationized cotton fabrics by dipping method. In this procedure, pieces of cotton fabrics (0.25 g) were impregnated in distilled water and stirred till temperature reached 90 o C then palladium salt solution with speci c concentration (20 and 60 mM) was added with liquor ratio of 2:50 at two different pH (2 & 11.5) and left for continuous stirring at 90 o C for 30 minutes. Afterward, the fabric pieces were air dried before they were instrumentally analyzed. Table  1 represented the samples that were prepared in the current approach under different experimental conditions. Characterization and instrumental analysis Geometrical shape and size distribution of the self-implanted palladium nanopanciles were estimated by using a high-resolution transmission electron microscope (JEOL-JEM-1200; Japan). Size distribution of palladium nanopanciles was evaluated with 4 pi analysis software (from USA) for at least 50 particles. The treated fabrics were characterized via the high-resolution scanning electron microscope (HRSEM Quanta FEG 250 with a eld emission gun, FEI Company, Netherlands). Elemental analysis was also estimated using an energy dispersive X-ray analyzer (EDAX AME-TEK analyzer). The infrared spectra of the treated fabrics were obtained by using a Jasco FT/IR 6100 spectrometer. Their spectral mapping was ranged from 4000 cm −1 to 400 cm −1 and were determined with 4 cm −1 resolution and 64-time scanning with a rate of 2 mm/sec. Additionally, the prepared fabrics were characterized by powder X-ray diffraction using X'Pert MPD diffractometer system from Philips, at room temperature. Diffraction patterns were estimated in the diffraction angle (2θ) range of 3.5 -50° using monochromatized (Cu Kα X-radiation at 40 kV, 50 mA and λ = 1.5406 Å). For each sample, estimation was estimation two different times, and the average was calculated.

Results And Discussion
Synthesis of palladium nanopanciles , but there were no researching approaches on the synergism between palladium nano-objects within cotton textiles nishing. Additionally, no researching reports were studied the direct implantation of palladium nanopanciles. Therefore, the leverage effects of direct implantation for palladium nanopanciles before and after fabric cationization on coloration, mechanical properties and UV-protection e ciency for cotton fabrics was the focus of this study.
In accordance to literature [], self-implantation of palladium nanopanciles within cotton fabrics could be hypothesized as the cellulosic building blocks of cotton fabrics with the terminal/alcoholic groups might assist in reduction of palladium ions for ingraining of palladium nanopanciles that could be highly stabilized within the intermolecular spaces of cotton polymeric matrix. Moreover, fabric cationization was performed for cotton before self-implantation of palladium nanopanciles in order to achieve the ful ll goal. Fabric cationization is supposed to enhance the implantation and stabilization of palladium nanopanciles within fabric matrix, while, such chemical modi cation acquired the fabric more accessible reducing groups to act more actively for ingrowth and stabilization of the requisite nanostructure ( Figure  1).

TEM and size distribution
The geometrical features and topography of the implanted palladium nanopanciles that were stably dispersed within the supernatant solution containing the treated fabrics were shown in transmission electron microscopic images from which the size distribution was estimated ( Figure 2). The microscopic images displayed the successful implantation of palladium nanopanciles with size distribution of 41.3 ±10.1 nm in alkaline medium (pH of 11.5) in the supernatant solution of native cotton treated with 20 mM of palladium chloride. Quite smaller sized palladium nanopanciles (3.2 ± 0.6 nm) were ingrained and well dispersed within the supernatant solution of cationized fabric treated with palladium precursor under the same experimental conditions, re ecting the pre-eminent effect of cationization in enhancement the accessibility of fabric/cellulosic backbone in the ingrowth of palladium nanopanciles. While, duplication of the percentage of quaternary ammonium salt exploited for cationization from 50-100% is insigni cantly affected on particle size (4.6±1.7 nm).

SEM
The topography of the surface of the pristine and cationized fabrics before and after implantation of palladium nanopanciles. In order to show the effects of palladium precursor concentration and cationization on the successive implantation of palladium nanopanciles, Scanning electron microscopic images (SEM images), energy dispersive x-ray (EDX signals), and the elemental analysis of cationized cotton, Pd-C4, Pd-CC(50)4, Pd-CC(100)3 and Pd-CC(100)4 were plotted in Figure 3. Before successive implantation of palladium nanopanciles, the surface of the cationized fabric seemed to be smoothy, and the specialized signals of carbon, oxygen, nitrogen and chlorine were obviously detected (Figure 3a). After implantation of palladium nanopanciles, the nanopanciles were clearly dispersed on the surface of the modi ed fabrics. Whereas, from EDX data, the characteristic peaks of carbon, oxygen, nitrogen, chlorine, and palladium were signi cantly presented, that a rmed the successive implantation of nanopanciles within the fabrics (Figure 3b). Moreover, cationization were shown to extensively enhance the implantation of palladium nanopanciles to be regulatory uploaded on the fabric surface as shown in Fig.   3b&c, while, duplication of the cationization percent from 50% (Fig. 3c) up to 100% (Fig. 3e) resulted in more accessibility for implanting of more condensed nanopanciles, which could con rm the postulated mechanism of palladium nanopanciles implantation. By comparing between the microscopic images of the modi ed fabrics after implantation of palladium nanopanciles (Fig. 3d &3e), increment of the concentration of palladium precursor resulted in more dense masses of nanopanciles were obviously shown on the surface of the fabric.

FTIR
The chemical composition of quaternary ammonium salt, pristine cotton, cationized cotton and fabrics immobilized with palladium nanopanciles was investigated via FTIR (Figure 4). From the spectral data it could be depicted that the quaternary ammonium salt, pristine and cationized cotton were characterized

Colorimetric data and mechanical properties
From the visual observation of the samples imaged in Figure 6 it could be noted that, treatment of fabrics with the demonstrated technique resulted in fabric coloration, while, the color is changed from white for native cotton to creamy white with cationization, and under different experimental conditions, the fabric color was developed to yellowish, brownish and lastly to dark black color. The color data of the pristine cotton and cationized cotton after implantation of palladium nanopanciles are presented in Table 2 and  Table 2, Yellowness index (YI) of the cationized cotton was extremely higher than that of pristine cotton fabrics. For fabrics prepared under alkaline condition, with increment of the concentration of palladium precursor and with duplication of the cationization percentage up to 100%, the lightness (L*) and whiteness index (WI) were signi cantly decreased, while, color strength (K/S), darkness (b*) and yellowness index are signi cantly increased. From the plotted results in Figure 6, it could be observably shown that, cationized fabrics were shown with higher absorbance and color strength values. Additionally, absorbance and color strength were extensively higher for fabrics prepared under alkaline conditions rather than that prepared under acidic pH with increment of palladium salt concentration and duplication of cationization percentage from 50% up to 100%. The color strength was evaluated to be 8. 9, 9.2, 9.2, 11.  Pd-CC (100)3 87.0 12 Pd-CC (100)4 84. 5 12 The effects for implantation of palladium nanopanciles within the polymeric matrix of both pristine and cationized cotton on the mechanical properties were monitored via estimation of tensile strength and elongation percentage and the results were tabulated in Table 3 Ultraviolet protection factor (UPF, Table 4) and transmission percent (T%, Figure 8) could be ascribed as key factors for evaluation of the ultraviolet protection action for all the prepared samples in the current study. The ultraviolet shielding property was analyzed within wavelength range of 280−400 nm, as shown in Fig. 7, for all the samples prepared from native and cationized cotton immobilized with palladium nanopanciles. Transmittance percent of cotton fabric is ca. 66% and 83.3 % for both UV-A and UV-B, respectively. As seen in Fig. 7, the blocking percent of the treated fabrics indicated with minor transmittance of UV radiation compared to untreated ones (UVA blocking percent 34.0% & UVB blocking16.7%), i.e., T% of all the prepared samples was observably diminished after implantation of palladium nanopanciles compared to that of the untreated fabric (UVA T% 66.0 & UVB T% 83.3). The blocking percentage of treated cotton fabrics showed that the percent of blocking for UV-B radiation is higher than that of UV-A for all samples prepared from native cotton, in contrast to that prepared from cationized cotton ( Table 4). The increment of concentration of palladium precursor (UVB T% for Pd-C3 was 1.6 %, while, for Pd-C4 was 1.0 %) and processing the palladium implantation under alkaline conditions resulted in lowering the detected transmission percent. Therefore, Pd-C4 sample (UVA T% 0.9 & UVB T% 1) was exhibited by the highest UVA & UVB blocking percent of 99.1% and 99.0 %, respectively, compared to the other three samples pristine cotton (Fig. 8a).   Emam et al. 2020b). Therefore, the results represented currently suggested that palladium nanopancilescoated fabrics could be expressed as potential candidates for ultraviolet shielding in textile functionalization, packaging applications and optoelectronics.

Conclusion
In the current study, for the rst time, self-implantation of palladium nanopanciles within cotton fabrics was proceeded in order to aid as strong ultraviolet absorbers to acquire the treated fabrics excellent ultraviolet protection potency with full shielding effects. The self-implanted palladium nanopanciles were immobilized within the polymeric matrix of both native and cationized cotton fabrics. For all the prepared specimens, the effects of the concentration of palladium precursor, pH, and cationization percentage on the particle size of the implanted nanopanciles, in addition to, the color coordinates, yellowness index, whiteness index, color strength, tensile strength, elongation percentage were monitored. From all of the illustrated data it could be summarized that, palladium nanopanciles aided superiorly as strong