Enhancing the formation and capacitance properties of interfacial polymerized polyaniline nanofibers by introducing small alcohol molecules

Abstract

Three kinds of polyaniline (PANI) nanofibers were prepared by introducing small alcohol molecules including methanol and ethanol as co-solvents into aqueous phase in the interfacial polymerization. The influences of alcohols on the morphology, microstructure, and electrochemical behaviors of PANI nanofibers were investigated by field emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, as well as electrical and electrochemical measurements. It is found that the growth and migration of PANI nanofibers were obviously suppressed due to the hydrogen bonding between polymer chains and alcohol molecules. An improvement on the electrochemical performances could be achieved by adding alcohol molecules especially ethanol into aqueous medium. The specific capacitance was 1017, 1031, and 1042 F g−1 at the scan rate of 5 mV s−1 and 444, 463, and 489 F g−1 at the current density of 1 A g−1 for the PANI nanofibers prepared without alcohol as well as with methanol and ethanol, respectively. The increase in specific capacitance could be contributed to the formation of the nanofibers with larger length to diameter ratio and higher orientation of polymer chains, which could provide shorter ion diffusion path, enhance the electroactive regions, and increase the electrode/electrolyte contact area. This study therefore provides an efficient modified interfacial polymerization for fabricating PANI nanofibers with more desirable morphology and better energy storage performance.