Oxidative graft polymerization of aniline on modified Si(100) surface

Abstract

Chemical modification of the argon plasma-pretreated Si(100) surface by UV-induced surface graft polymerization with either glycidyl methacrylate (GMA) or glycidyl acrylate (GA) was carried out. The GA graft polymerized Si substrate was further subjected to coupling reaction with aniline (An) and finally oxidative graft polymerization of An. The composition and microstructure of the graft-polymerized Si(100) surfaces were studied by X-ray photoelectron spectroscopy (XPS) and imaging XPS, respectively. The graft concentrations of the GMA polymer, GA polymer, and An polymer increased with increasing concentration of the respective monomer used for graft polymerization. The graft polymerization efficiency of GA on the Ar plasma-pretreated Si(100) was much higher than that of GMA. Ethanol, when used as a solvent, catalyzed the coupling reaction of the epoxide groups of GA with An and should be of more than 40 vol% in concentration to achieve the optimum effect. The protonation-deprotonation characteristics, interconvertible intrinsic redox states, and metal reduction behavior of the polyaniline (PANI) chains, obtained from subsequent oxidative graft polymerization of An on the modified Si(100) surface, were grossly similar to those of the PANI homopolymer. The resistance of the modified Si(100) surface from consecutive graft polymerization with GA and An was on the order of 107 Ω/sq.