Syntheses of polyaniline and polyaniline filled with silver particless using pulsed inductively coupled plasma

Abstract

Polyanilines were synthesized using pulsed plasma generated from a theta-pinch device and a pulsed inductively coupled plasma (PICP) device at same pressure of 2 Pa and discharging current of 125 kA. While a voltage of 20 kV was applied to the former, a voltage of 9.5 kV was used in the latter. The numbers of the plasma shots were varied from 5, 10, 15, 20, 25, to 30 shots and different types of gases including argon, oxygen and nitrogen were used. These parameters significantly affected the chemical structures of the obtained polyanilines as revealed by FTIR spectra. Polyanilines doped with sulfuric acid had better electrical and thermal properties than those doped with hydrochloric acid. The suitable condition that yielded polyaniline with highest conductivity of 10⁻⁷ S.cm⁻¹ was at 20 shots of argon. In addition, it was found that using PICP device yielded polyanilines with better properties than using theta-pinch device. Therefore, PICP device was used for preparing polyanilines filled with silver particles. Polyanilines filled with silver particles can be synthesized in one step by using the mixture of aniline in nitric acid solution and silver nitrate solution in plasma polymerization. The numbers of the plasma shots, the gas types and the concentration of silver nitrate solution were varied. These parameters significantly affected the chemical structures of the obtained polyanilines as revealed by FTIR spectra. Electrical conductivity of these polyanilines was about 10⁻⁴ S.cm⁻¹ higher than that of unfilled polyanilines. They also had better thermal stability. FE-SEM images showed the spherical silver particles with diameters about 50-80 nm and the nanofibrils of polyaniline with diameters about 50-100 nm.