Branched and Responsive Antimicrobial Polymers Based on Modified PVA for Functionalizing of Cellulose Fibres

Abstract

In this work polyvinyl alcohol (PVA) was modified via grafting or coupling with the guanidine-based antimicrobial polymer using epichlorohydrin as a crosslinking agent. The resulting polymer was tested for its charge density and inhibition against E.coli. The modified PVA adsorbed onto cellulose fibres via electrostatic association; thus resulting in the hand-sheets (or paper) with improved antimicrobial activity. As a further extension of this work, the temperature-responsive antimicrobial polymers were prepared based on acetalyzed PVA (APVA) grafted with guanidine-based polymer chains. In conjunction with anionic APVA copolymer (APVA copolymerized with sodium acrylate), the cationic and responsive APVA formed a unique antimicrobial polymer system via layer by layer (LbL) assembly, which could adsorb on fibre surfaces and be incorporated into cellulose fibre networks, leading to the functionalizing of cellulose fibres. The lower critical solution temperature (LCST) of APVA copolymer could be tailored by controlling the degrees of acetalysis (DA) and co-monomer ratios. AFM images obtained to reveal the roughness of the surfaces; while the antimicrobial test proved that cellulose fiber assembled with APVA-based multilayers exhibited excellent antimicrobial activity against E.coli.