Reactive diluent with quaternary ammonium salts (RDQ) for UV-curable antistatic coating was synthesized by reacting glycidyl methacrylate (GMA) and piperazin with dropping the methansulfonic acid. In order to compare the curing behavior of RDQ with commercial monomers, the photopolymerization of RDQ, 1,6-hexandiol diacrylate (HDDA) and 1,6-hexandiol dimethacrylate (HDDMA) were studied by using real-time IR spectroscopy. Surface properties such as surface resistance, pencil hardness, and solvent resistance of the cured films containing RDQ were investigated. When used as a reactive diluent in the UV-curable coating formulation, the RDQ imparted excellent antistatic properties to the final material. The results of an Fourier transform infrared/attenuated total reflectance (FTIR/ATR) depth profile analysis show that RDQ molecules are more concentrated near the surface within a micrometer-thick layer, indicating that existence of the ionic components in the surface layer is responsible for antistatic property. Film cured from the formulation containing 12 wt % of RDQ showed the best mechanical properties with reasonable surface properties. 0 2002 John Wiley Sons, Inc.