Micro-Bubble Sonic-Electrochemical Preparation of Polyaniline

Abstract

Polyaniline is one of the most promising conductive polymers because the polymer can prepared in water medium, no requirement of inert gas in the preparation process. Further, aniline monomer is low cost for production. Polyaniline is prepared by oxidative chemical polymerization with an aid of oxidizing agent such as ammonium persulfate or H2O2 in the presence of iron catalyst, or electrochemical polymerization in the water. Chemical polymerization affords to synthesize polyaniline in the bulk state or powder. However, deposition onto the metal electrode for applications is somewhat difficult because infusible and insolubility in common organic solvent. On the other hand, electrochemical polymerization allows producing thin film deposited onto the electrode. The thin polyaniline film on the electrode is valid for applications such as battery, anti-corrosion films, and gas-sensors. We recently developed electrochemical polymerization of aniline with bubble air. Nano-bubble has been paid attention for various industrial fields [1]. The polyaniline thus prepared by the micro-bubble electrochemical polymerization has micro-pores on the surface. The size of micro-pores can be tuned by amount and size of micro-bubbles during the polymerization process through tuning of application voltage. The micro-bubble consists of H2 gas as a result of electrolysis of water. Polymerization is occurred during discharge of H2 gas from the anode side with producing micro-pores, resulting polyaniline with micro-pores. We attempt capture of pollens in the air from the plant with the micro-pores on the polyaniline surface for solution of pollen allergy. The form of micro-pores on the conductive polymer has possibilities for cleaning of air by remove of pollens, removal micro-sands, dusts, oil, and poison gas to improve the environment. Combination of good redox character and the micropores form can lead to construction of electro-active clean up system. Sonoelectrochemistry has opened a new avenue for electrochemical applications [2,3]. In this paper, we introduce preparation method of polyaniline having micro-pores by micro-bubble electrochemical polymerization with sonic vibration. Surface observation of the polymer with a scanning electron microscopy and discussion of the pore size and effect of the surface state with application of high-power sonic are reported.