超临界二氧化碳流体环境中导电聚吡咯复合材料的制备

以聚苯乙烯(PS)和锌盐中和的磺化聚苯乙烯(Zn-SPS)膜为基体, 在超临界二氧化碳(SC-CO₂)环境中用化学氧化法原位制备了聚吡咯(PPy)导电复合材料. 由于SC-CO₂对聚合物基体的强溶胀作用, 吡咯分子高效地扩散到基体内部进行聚合而形成导电通路, 得到比传统的水溶液法更高的电导率. 聚合物基体的性质对复合材料的导电性和形貌产生重要影响. 在相同条件下, Zn-SPS/PPy的电导率比PS/PPy高3~4个数量级, 而它们的体积逾渗阈值分别为2.7%和6.2%, 远远低于理论预测值(16%).

Preparation of Conductive PPy Composites Under Supercritical Carbon Dioxide Circumstance

Electrically conductive composites were prepared via the chemical oxidative polymerization of pyrrole monomer in polystyrene(PS) and zinc neutralized sulfonated polystyrene(Zn-SPS) films under supercritical carbon dioxide(SC-CO_(2)) circumstance.The strong swelling effect of SC-CO_(2)made polypyrrole(PPy) particles not only formed on the surface,but also incorporated into the film,resulting in a homogenous structure and a relatively higher conductivity.By comparison,the composite prepared in aqueous solution shows a skin-core structure and a conductivity of 3 to 4 orders of magnitude lower than that of the former due to the diffusion controlled process of pyrrole monomer.The percolation thresholds of PS/PPy and Zn-SPS/PPy composites are 6.2% and 2.7% of volume fractions of PPy,respectively,much lower than a theoretically predicted value of 16%.Moreover,the conductive composites prepared under SC-CO_(2) circumstance show higher thermal stability,especially in the high-temperature region.