Advanced cotton fibers exhibit efficient photocatalytic self-cleaning and antimicrobial activity

Sodium alginate/chitosan-coated TiO2NPs hybrid fiber with photocatalytic self-cleaning property, UV resistance and enhanced tensile strength

SA/CS-coated TiO₂NPs hybrid fibers with photocatalytic self-cleaning properties, UV resistance and enhanced tensile strength were successfully prepared by adding CS-coated TiO₂NPs to SA matrix. The FTIR and TEM results demonstrate the successful preparation of CS-coated TiO₂NPs core-shell structured composite particles. SEM and Tyndall effect results showed that the core-shell particles were uniformly dispersed in the SA matrix. When the content of Core-shell particles increased from 0.1 to 0.3 wt%, the tensile strength of SA/CS-coated TiO₂NPs hybrid fibers increased from 26.89 to 64.45 % compared with SA/TiO₂NPs hybrid fibers. The SA/CS-coated TiO₂NPs hybrid fiber (0.3 wt%) exhibits excellent photocatalytic degradation performance, achieving a 90 % degradation rate for the RhB solution. And the fibers also exhibit outstanding photocatalytic degradation performance towards various dyes and stains commonly encountered in daily life, including methyl orange, malachite green, Congo red, coffee and mulberry juice. The UV transmittance of the SA/CS-coated TiO₂NPs hybrid fibers decreased significantly from 90 % to 75 % with the increase in core-shell particle addition, and correspondingly, the UV absorption capacity increased. The SA/CS-coated TiO₂NPs hybrid fibers prepared lay the groundwork for potential applications in various fields, including textiles, automotive engineering, electronics and medicine.

Physical and Mechanical Characterization of a Functionalized Cotton Fabric with Nanocomposite Based on Silver Nanoparticles and Carboxymethyl Chitosan Using Green Chemistry

Cotton is the most widely used natural fiber for textiles but its innate capacity to absorb moisture, retain oxygen, and high specific surface area make it more prone to microbial contamination, becoming an appropriate medium for the growth of bacteria and fungi. In recent years, the incorporation of silver nanoparticles in textile products has been widely used due to their broad-spectrum antibacterial activity and low toxicity towards mammalian cells. The aim of the current study is to synthesize and characterize a nanocomposite based on silver nanoparticles and carboxymethyl chitosan (AgNPs-CMC), which was utilized to provide a functional finish to cotton fabric. The scanning electron microscope (SEM) to produce a scanning transmission electron microscope (STEM) image showed that the nanocomposite presents AgNPs with a 5–20 nm size. The X-ray diffraction (XRD) analysis confirmed the presence of silver nanoparticles. The concentration of silver in the functionalized fabric was evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES), which reported an average concentration of 13.5 mg of silver per kg of functionalized fabric. SEM showed that silver nanoparticles present a uniform distribution on the surface of the functionalized cotton fabric fibers. On the other hand, by infrared spectroscopy, it was observed that the functionalized fabric variation (compared to control) had a displaced peak of intensity at 1594.32 cm−1, corresponding to carboxylate anions. Similarly, Raman spectroscopy showed an intense peak at 1592.84 cm−1, which corresponds to the primary amino group of carboxymethyl chitosan, and a peak at 1371.5 cm−1 corresponding to the carboxylic anions. Finally, the physical and mechanical tests of tensile strength and color index of the functional fabric reported that it was no different (p ˃ 0.05) than the control fabric. Our results demonstrate that we have obtained an improved functionalized cotton fabric using green chemistry that does not alter intrinsic properties of the fabric and has the potential to be utilized in the manufacturing of hospital garments.

Study of the Effect of Titanium Dioxide Hydrosol on the Photocatalytic and Mechanical Properties of Paper Sheets

Different amounts of a stable aqueous TiO₂ hydrosol were used to fabricate paper sheets having photocatalytic activity. The TiO₂ hydrosol was prepared in aqueous medium using titanium butoxide as precursor and acetic acid as catalyst for the hydrolysis of titanium butoxide. An aging process at room temperature and atmospheric pressure was finally applied to obtain crystalline anatase TiO₂ hydrosol. The effects of different TiO₂ hydrosol loadings on the mechanical strength and barrier properties of modified paper sheets were investigated in detail. The photocatalytic behavior of TiO₂-modified paper sheets was investigated as well using methylene blue (MB) as target pollutant.