Effect of Alkyl Derivatization on Several Properties of N-Halamine Antimicrobial Siloxane Coatings

Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the I position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain length, in contrast to reported observations for biocidal quaternary ammonium salt derivatives. The stabilities of the derivatives toward hydrolyses and ultraviolet light exposure have also been found to not be dependent upon the nature of the alkyl substituent group. These observations led to the conclusion that the 5,5-dimethyl derivative would be recommended for use, since it is the least expensive alternative.