Pulse Potentiostatic Deposition And Electrochemical Properties Of Polyaniline

Electropolymerization of aniline was conducted on carbon cloth in a solution of0.2M aniline and0.5M H2SO4through pulse potentiostatic method to afford polyaniline (PANI) films. The PANI films were characterized by FT-IR and UV-vis spectrometries. Surface morphologies of PANI were investigated by SEM. The electrochemical activities, electrocatalytic properties and pseudocapacitve properties of PANI were studied by cyclic voltammetry and chronopotentiometry. The results show that one dimensional growth of PANI was controlled by pulse potentiostatic method and the PANI (PPM) existed in nanofibrous structure, while the PANI made through conventional potentiostatic method (PM) displayed irregular shapes. The results of cyclic voltammetry and chronopotentiometry of three PANI films obtained by pulse potentiostatic and three films by potentiostatic methods indicated that the electrochemical activities of PPM was twice higher than that of PM; the specific capacitance of the PPM film increased39%compared to that of the PM film. In addition, hydrolysis of PANI was depressed in pulse potentiostatic deposition.To investigate the influence of pulse potential on aniline polymerization, electropolymerization was conducted at different upper potential limit Eu,0.7,0.75,0.8,0.85and0.9V. The electrochemical activities, pseudocapacitve properties, polymer chain conformations and surface morphologies of the obtained PANI films PPM00.7V, PPM0.75V, PPM0.8V, PPM0.8V and PPM were studied by cyclic voltammetry, chronopotentiometry, UV-vis spectrometry and SEM. The results show that the higher upper potential limit like0.8to0.9V resulted in one dimensional growth of PANI, and the PANI with expanded coillike conformation was obtained with the upper potential limit of0.85and0.9V, which displayed higher electroactivity and specific capacitance.Electropolymerization of aniline was also conducted in solutions containing different amount of H2SO4(0.1,0.2,0.3,0.4and0.5mol·L-1) by pulse potential method with the upper potential limit of0.9V to investigate the influence of acidity. The electrochemical activities, pseudocapacitve properties, polymer chain conformations and surface morphologies of the obtained PANI films PPM0.1M, PPM0.2M, PPM0.3M, PPM0.4M and PPM were studied by cyclic voltammetry, chronopotentiometry, UV-vis spectrometry and SEM. The results show that along with the increase in acidity, one dimensional growth of PANI is promoted, resulting in better contact of active materials with electrolyte and so higher electroactivities and specific capacitance.