Electrochemical synthesis of PEDOT and PPP macroporous films and nanowire architectures from ionic liquids

We report on the electrochemical synthesis of macroporous films and on nanowire architectures of conducting polymers from ionic liquids. The electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) and of poly(para-phenylene) (PPP) from the air and water stable ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]TFSA) and from 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIm]FAP) within the voids of a polystyrene opal structure on gold and on platinum substrates yield macroporous films. For this purpose, polystyrene spheres with an average diameter of about 600 nm were applied onto the employed electrodes by a simple dipping process resulting in a layer thickness of about 10 mu m. The macroporous films turn into yellow, orange, blue, and green colors owing to the Bragg reflection of the incident artificial white light. PPP and PEDOT nanowires were electrochemically prepared in a track-etched polycarbonate (PC) membrane with an average pore diameter of 90 nm. One side of the membrane was sputtered with a thin gold film to serve as a working electrode. Electrodeposition occurs along the pores of the template. Nanowires with an average diameter of 90 nm and a length of up to 17 mu m can be easily synthesized by this electrochemical template-assisted method. Such materials are of interest as catalyst in metal/air batteries and as cathode material in, e.g., microbatteries.