An organic-inorganic hybrid material was prepared through the addition of nanometer fumed silica partly modified by dimethyl dichlorosilane into a water-borne poly(urethane acrylate) (PUA) anionomer. A PUA/silica hybrid film was made via ultraviolet curing. The mechanical properties of the hybrid film were studied. The tensile strength, elongation at break, pendulum hardness and the glass-transition temperature of the hybrid material increased with increasing content of silica. Scanning electron microscopy showed an asymmetrical distribution of modified silica in PUA. Atomic force microscopy demonstrated that silica particles could make the surface of the film smooth. (C) 2004 Wiley Periodicals, Inc.