Heterocyclic and acyclic silane monomers and siloxane polymers, and their halogenated derivatives, are provided for the purpose of functionalizing surfaces or materials so as to render them biocidal upon exposure to oxidative halogen solutions. The biocidal function can be imparted either before or after bonding or adhesion to the surface or material. The biocidal surfaces and materials can then be used to inactivate pathogenic microorganisms such as bacteria, fungi, and yeasts, as well as virus particles, which can cause infectious diseases, and those microorganisms which cause noxious odors and unpleasant coloring such as mildew. Examples of surfaces and materials which can be rendered biocidal in this invention include, but are not limited to, cellulose, chitin, chitosan, synthetic fibers, glass, ceramics, plastics, rubber, cement grout, latex caulk, porcelain, acrylic films, vinyl, polyurethanes, silicon tubing, marble, metals, metal oxides, and silica.