Influence of side chain structure on the thermal and antimicrobial properties of cationic methacrylic polymers

Abstract

A novel methacrylic monomer, 2-(((2-(4-methylthiazol-5-yl)ethoxy)carbonyl)oxy)ethyl methacrylate (MTZ), containing in the lateral chain both hydrolytically sensitive carbonate and thiazole groups has been firstly described. Posterior, it was free-radical polymerized and copolymerized with acrylonitrile in anhydrous solution of dimethylsulfoxide, with the purpose of investigate the influence of its chemical and structural characteristics on the antimicrobial activity. Cationic antimicrobial polymers were subsequently obtained by alkylation reaction with methyl and butyl iodide agents. Their thermal behavior was analyzed in all series, modified and unmodified copolymers in terms of glass transition temperature and thermal stability. The antimicrobial activity in solution was tested against Gram-positive Staphylococcus aureus and Staphylococcus epidermidis, Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria, and Candida parapsilosis yeast and further correlated with their zeta potential. Then, blends of these cationic polymers with commercial polyacrylonitrile as matrix material were prepared and their effectiveness as antimicrobial coating was determined against Gram-negative Escherichia coli bacteria. In addition, and due to the presence of the carbonate groups in the copolymer structures, these systems could be further used as antimicrobial releasing coatings in alkaline conditions.