Influence of Supporting Salts to Shape of the Microstructures Formed during the Electropolymerization of Pyrrole

Background: We previously reported that polypyrrole microtubes (ca. 10 and 0.4 um in length and diameter, respectively) form on the surface of working electrode during the electrochemical polymerization of pyrrole without any shape-guiding template. However, the influence of supporting salt to the shape of the mocrostructure during the electrochemical polymerization of pyrrole was not well studied. Objective: In first part of this short article, we briefly report influence of supporting salt to the shape of the mocrostructure during the electrochemical polymerization of pyrrole. In second part we briefly reviewed recent patents relevant to conducting polymers. Method: Electrochemical polymerization of pyrrole was conducted using a designed supporting salt with three-electrode setup. Scanning electron microscopic (SEM) observations of the microstructures were carried out. Results: When sodium p-toluenesulfonate was used as a supporting salt, usually microtubes were formed, but sometimes, “micro-flowers” or “micro-corals also were formed. When sodium 1,3-benzenesulfonate was used “micro-vases” or “micro-cactuses” were formed. In the case of lithium chloride “microcucumbers” were formed. Conclusion: We found that the shape of the spontaneously formed microstructure is evidently influenced by the kind of the supporting salt.