Electropolymerization of polyaniline in ionic liquid ([bmim]PF6)/water microemulsion

Microemulsion polymerisation, an important way to synthesise the controllable size and shape of nano-scale materials, has received increasing attention. In this study, polyaniline (PANI) has been prepared by cyclic voltammetry in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6)/water (IL1/W) microemulsion. The electrochemical properties of the PANI prepared in IL1/W microemulsion are compared with those of the PANI polymerised in the conventional acidic aqueous solution and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4)/water (IL2/W) microemulsion. The results show that the PANI electrodes prepared in IL1/W microemulsion have the highest capacity. Also, the effects of the potential cycle number on the specific capacitance and electrochemical characteristics of the PANI film electrodes are discussed in detail. The result shows that the specific capacitance of the PANI film obtained by 50-cycle electropolymerisation in IL1/W microemulsion is 334 F g(-1) at the charge-discharge current density of 2 mA cm(-2). The scanning electron microscopy image indicates that the PANI film obtained in IL1/W microemulsion presents cauliflower-like morphology, and the energy-dispersive X-ray spectroscopy result suggests that the polymer is co-doped with SO42- and PF6-.