Synthesis of a Water-Soluble Siloxane Copolymer and Its Application for Antimicrobial Coatings

Copolymers of ail N-halamine siloxane and a quaternary ammonium salt siloxane were prepared using 5,5-dimethylhydantoin and trimethylamine as functional groups. The Solubility of this siloxane copolymer in water was dramatically improved over that of a hydantoinyl siloxane homopolymer developed earlier. The biocidal activity of cotton swatches coated with the copolymer was evaluated against S. aureus and E. coli O157:H7; the antimicrobial fabric with 0.23%-0.26% chlorine loading could inactivate 10(7) colony forming units (CFU) of bacteria within 1-5 min of contact. It was observed that a 1 wt % coating bath could provide a coating that Could be chlorinated to greater than a 0.20% chlorine loading for a copolymer having a 9:1 ratio of hydantoin to quat moieties. The stability of the oxidative chlorine loading on the cotton swatches was, not affected by the presence of the very hydrophilic quat functional group. Use of the copolymer in an antimicrobial coating application will be desirable because no organic solvent is needed for the preparation of a coating bath for textile materials.