INSITU CONDUCTIVITY ELECTROCHEMISTRY OF CONDUCTIVE POLYMERS - POLY(3-METHYLTHIOPHENE) AND POLYTHIOPHENE

In situ monitoring of conductivity and potential response of conductive polymers during electrochemical process had been described. A renewable carbon fibre array ring-glassy carbon disk electrode was used for this purpose. Poly(3-methylthiophene) and polythiophene were investigated with this method, and some 5 orders in magnitude of conductivity changes were observed during the electrochemical redox process.

ELECTROLYTE EFFECTS ON THE ELECTROCHEMICAL POLYMERIZATION OF N-BENZYLANILINE

The electrochemical behaviour of N-benzylaniline polymerization is determined by the nature of the electrolyte. The voltammograms for a poly-N-benzylaniline modified Pt electrode prepared in 1 M HCl (abbreviated to PBAn(HCl)), and 1 M H2SO4 (PBAn(H2SO4)) tested in 1 M hydrochloric, sulfuric, and perchloric acid were almost superimposable. The polymer film electrode prepared in 1 M HClO4 (abbreviated to PBAn(HClO4)) is electroinactive, and exhibits only charging behaviour in 1 M HClO4 solution and can be activated in hydrochloric or other acid electrolytes with a smaller anion. These interesting phenomena are explained in terms of the anions catalyzing the loss of benzyl groups.

LIGHT-ASSISTED OXIDATIVE DOPING OF POLYANILINES

A novel doping phenomenon of fully reduced polyaniline and poly-o-methyl-aniline, "light-assisted oxidative doping", was found for the first time. The doping reaction was followed by FTIR, UV-VIS, ESR and electrical conductivity measurements. It was shown that the fully reduced polyanilines in the form of HCl-salts undergo a spontaneous transition from an insulator or semiconductor to a conductor when exposed to air and light, and their final molecular chain structures are analogous to those found in HCl-doped common polyanilines.

THE INFLUENCE OF PROTONIC ACIDS ON THE CHEMICAL POLYMERIZATION OF ORTHO-METHYLANILINE

The chemical polymerization of ortho-methylaniline (MAn) is performed in aqueous solution of six protonic acids. The MAn polymerization conversion, and the electrical conductivity and doping level as well as molecular chain structure of the polymers obtained depend not only on the acid concentration but also on their acidity and molecular size.

聚苯胺纳米结构的制备及其防腐性能的研究

从纳米结构自组装和聚苯胺的刚性分子链出发，本文分别采用界面聚合法和直接混合反应法制备了一维聚苯胺纳米结构，探讨了产物结构及形成机理，并对其防腐蚀性能和机理进行了研究。主要研究结果如下： 1. 直接混合反应法是一种有效的制备聚苯胺纳米结构的方法，其产率高于界面聚合法。不同掺杂酸对产物结构和产率存在较大影响。 2. 在硫酸体系中，采用直接混合反应法合成了聚苯胺纳米纤维，其直径约为60-100 nm，长度达到几个微米，导电率为6.0 S/cm。综合考虑产物形貌、导电率和产率的最优合成条件为：硫酸浓度1 mol/L，苯胺与过硫酸铵配比0.8，反应时间16 h。 3. 在醋酸体系中，采用直接混合反应法可合成出纳米纤维和纳米管，反应物配比是产物形貌和产率的主要影响因素。在醋酸浓度为1 mol/L，苯胺浓度为0.2 mol/L，过硫酸铵浓度为0.1 mol/L，反应时间为24 h的条件下，可以制备得到螺旋状聚苯胺纳米纤维。 4. 电化学测试技术研究表明，直接混合反应法合成的聚苯胺纳米纤维具有比常规聚苯胺更好的防腐蚀性能；在3.5%NaCl溶液中，掺杂态聚苯胺产物的防腐蚀性能优于解掺杂态聚苯胺产物。聚苯胺在低碳钢表面钝化形成的氧化膜与纯聚苯胺涂层均具有一定防腐时效性，但防护时间较短。要获得更长期的防腐效果，需开发聚苯胺与常规涂层的混合体系。