Functional surface engineering of Kosa silk fabrics via graft copolymerization: Structural and antibacterial insights

Natural Kosa silk (KS), a protein-based textile, is susceptible to microbial degradation during use and storage. This study surface-modified KS through thermochemical grafting of quaternary ammonium monomers vinyl benzyltrimethylammonium chloride (VBT) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MAETC) using redox system. Reaction parameters were systematically optimized, yielding maximum grafting efficiencies of 17.1% (VBT) and 14.5% (MAETC). These levels imparted enhanced thermal stability and potent antibacterial properties to the functionalized silk, as confirmed by characterization techniques. The modified fabrics showed strong antimicrobial activity against Gram-negative Escherichia coli (zone of inhibition: 45 ± 2.25 mm) and Gram-positive Staphylococcus aureus (41 ± 2.05 mm).