WATER-DISPERSED POLYTHIOPHENE WITH DIFFERENT MORPHOLOGY AND SIZE: SYNTHESIS, CHARACTERISATION AND ANTICORROSION PERFORMANCE IN WATERBORNE EPOXY COATING

摘要

Water-dispersed polythiophene was prepared through chemical oxidative polymerisation using anhydrous FeCl_2 as catalyst, H_2O_2 as oxidant and acetonitrile as co-solvent. The stirring rate, the ratio of thiophene/FeCl_2/H_2O_2, and the ratio of DIW (deionised)/ acetonitrile were varied step by step to study their influence on morphology and size of the polythiophene. The morphology and size of polythiophene were characterised by SEM and the performance of water-based coating containing polythiophene was investigated by electrochemical impedance spectroscopy(EIS) technique and salt spray test. The studies indicate that the morphology and size of polythiophene microspheres are affected by the stirring rate of polymerisation, the ratio of thiophene/ FeCl_2/H_2O_2 and the co-solvent. Moreover, the coating with smaller nanopolythiophene microspheres or network polythiophene shows more excellent anticorrosion than the others. In parallel, the desired anticorrosion could be reached by obtaining smaller nanopolythiophene microspheres or network polythiophene coating.