dently for each occurrence Cl, Br, or I; and [0028] n is an integer less than or equal to about 1500. [0029] In a preferred embodiment, the invention comprises Poly(4-vinyl-N-alkylpyridinium bromide) or poly(methacryloyloxydodecylpyridinium bromide) (MDPB) covalently attached to a glass surface.