邻苯二胺的电聚合及膜氧化还原过程的研究

Study of Electropolymerization of o Phenylenediamine and Redox Process of Polymer Films

用循环伏安法和电化学石英晶体微天平（ＥＱＣＭ） 研究了０－１ ｍｏｌ／ＬＨ２ＳＯ４ 溶液中邻苯二胺在金电极上的电化学聚合过程及聚合膜（ＰＯＰＤ） 的电化学性质． 邻苯二胺的起始氧化电位约为０－４ Ｖ（ ｖｓ－ＳＣＥ） ． 从ＥＱＣＭ 数据得知在酸性水溶液中邻苯二胺较易发生聚合，在邻苯二胺单体氧化的同时电极上就有聚合物沉积引起表面质量增加． 质子在ＰＯＰＤ 膜氧化还原过程中起着非常重要的作用，ＰＯＰＤ 膜质子化（ 氧化） 或去质子化（ 还原） 的同时使阴离子嵌入膜中或脱出，使ＥＱＣＭ电极频率发生变化，根据Ｓａｕｅｒｂｒｙ 方程计算了阴离子迁嵌入或迁脱出量及其随ＰＯＰＤ膜质量和电位扫描速度的变化．

The electropolymerization of o phenylenediamine(OPD) on gold electrode and the redox behavior of poly( o phenylenediamine)(POPD) films in sulfuric acid solutions have been studied by cyclic voltammetry and electrochemical quartz crystal microbalance(EQCM). The decrease in the resonant frequency of the quartz crystal during electropolymerization of OPD demonstrated that the deposition of the polymer films occurrs mainly in the potential range >0 5 V, at which the monomers are anodically oxidized. It is revealed that the protonation and deprotonation play an important role in the redox process of POPD films. The protonation during the reduction of POPD film induces the intercalation of anions, whereas the deprotonation in the oxidation of POPD film makes the escape of anions from the film. The quantity of anions intercalated into POPD film has been calculated according Sauerbry equation from the frequency decrease of EQCM electrode. Its values are in the range of 10 -9 to 10 -8 mol/cm 2 and varies with the mass of POPD film as well as with the scan rate of electrode potential.