Environmentally-Friendly RF Plasma Treatment of Thai Silk Fabrics with Chitosan for Durable Antibacterial Property

Abstract

Abstract. A 13.56 MHz RF plasma discharge was successfully utilized to activate and coat Thai silk fabrics with chitosan for durable antibacterial property. Uncolored and untreated Thai silk fabrics were activated in Ar plasma for 5 minutes with an optimized RF power of 120 W under Ar pressure of 0.8 Torr. After plasma activation, specimens were submerged and stirred in a 1% (w/v) chitosan solution. FTIR analysis confirmed the presence of chitosan on the silk fabrics. From SEM analysis, chitosan was observed to coat silk fibers almost everywhere. RF plasma treated fabrics were able to absorb the chitosan solution substantially faster than those without the treatment. Another benefit of increased hydrophilicity is the ability of the treated fabrics to allow human perspiration to flow through more effectively, providing additional comfort when worn in tropical-zone countries. Antibacterial properties against E. coli and S. aureus reduced with increasing washing cycles dropping to approximately 95% after 5 rounds of washing. Extrapolation of linear trend lines revealed that for the case of E. coli, it will take approximately 16 washing cycles to reduce the antibacterial ability to 90%. For the case of S. aureus, it will take approximately 10 washing cycles to reduce the antibacterial ability to 90%. Fabrics without RF plasma treatment prior to chitosan solution submersion will have their antibacterial ability for E. coli and S. aureus reduced to 90% after only about 5 washing cycles. Thus, RF plasma treatment can effectively induce chitosan to provide a strong and durable coating for Thai silk fabrics, thus, offering a new, very environmentally-friendly coating technique for Thai silk with chitosan for potential use in the textile industry.

Chitin/Chitosan: Versatile Ecological, Industrial, and Biomedical Applications

“…Chitosan per se or blends of chitosan-based composites deposited onto textiles fabrics were mostly tested for durable antibacterial activity (nearly all antibacterial studies include E. coli and S. aureus that represent correspondingly Gram-negative and Gram-positive bacteria). Coated Thai silk fabric with chitosan using radio frequencies plasma treatment exhibited antibacterial effects (Wongsawaeng et al 2017), and polyester/cotton fabric treated with chitosan can be used as an alternative to the antibacterial triclosan (Ranganath and Sarkar 2014). Chitosan grafted on cotton (Ferrero et al 2015) or on wool (Periolatto and Ferrero 2013) fabrics using UV irradiation bestowed antibacterial activity after many washing cycles.…”

Study of physico-chemical and antibacterial properties of DBD plasma treated ahimsa silk coated with natural active agent

“…Rani et al used DC glow discharge plasma and ZnO nanoparticles to make tasar silk antimicrobial [14]. RF plasma-treated Thai silk with chitosan exhibited antibacterial characteristics, while N 2 plasma increased cell adhesion [15,16].…”

Functionalization of silk fabric using hyperbranched polymer coated attapulgite nanoparticles for prospective UV-resistance and antibacterial applications

“…The functional silk fabrics possessed excellent anti-UV property [10]. Wong et al utilized chitosan via a 13.56 MHz RF plasma to treat silk fabrics for durable antibacterial property [11]. After 5 washing cycles, the antibacterial rate of finished silk fabrics decreased from 100% to 88.78% to E. coli, from 100% to 90.26% to S. aureus.…”