Durable antibacterial cotton fiber surface fabricated by the thiol-ene click reaction between eugenol and L-cysteine

Cotton fabric plays an important role in the textile industry, but suffers from bacterial proliferation. The incorporation of naturally occurred phenols onto cotton fiber surfaces has the potential to yield powerful antibacterial effects, yet a simple and feasible method for their covalent grafting is currently lacking. In this study, we present a cleaning technique for preparing antibacterial cotton fabrics by using eugenol (Eug) and L-Cysteine (Cys) as finishing agents. The reactive carboxyl group of Cys is utilized to link Cys molecules onto cotton fibers via an esterification, followed by linking Eug molecules to the Cys moieties through thiol-ene click reaction. Simulated reactions validate the chemical mechanism of the thiol-ene click reaction between Eug and Cys, confirming its feasibility for various applications. Experimental results demonstrate that the modified fabrics achieve high bacteriostatic reduction rates (BR) against both Escherichia coli and Staphylococcus aureus . It is inferred that the Eug moieties incorporated onto the cotton fibers furnish phenolic groups, which interact with saccharides and proteins to exert bactericidal effects. The resulting fabrics also display exceptional antibacterial durability, maintaining over 95 % antibacterial activity after enduring durability tests. Meanwhile, the original properties of the fabrics (strength, flexibility, etc.) are minimally affected by the modification process.