Preparation, surface properties, and antibacterial activity of a poly(dimethyl siloxane) network containing a quaternary ammonium salt side chain

To obtain a copolymer network with low surface energy and antibacterial properties, a series of hydroxyl-terminated poly(dimethyl siloxane)s (PDMSs) modified by a quaternary ammonium salt (QAS) side chain was synthesized via hydrolytic polycondensation and quaternization. The structures of the intermediate and final products were confirmed by Fourier transform infrared spectroscopy, H-1-NMR, and gel permeation chromatography. The results show that each step was successfully carried out, and objective products were obtained. The modified PDMSs were crosslinked with a commercial polyisocyanate to obtain cured QAS-modified PDMS coatings. The target functional coatings exhibited excellent antibacterial performance with a low surface energy. When the molar content of QAS in PDMS was varied from 10 to 30%, the critical surface energy of the coatings remained in the range 24.05-26.88 mN/m; this indicated that the coatings had minimal adhesion with fouling according to the Baier curve. The bactericidal tests showed that the antibacterial activity was independent of the PDMS molecular weight but was closely correlated with the QAS content in PDMS. The bactericidal rate of the coatings to Escherichia coli and Staphylococcus aureus was higher than 97% when the molar content of QAS in PDMS was above 20%. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41725.