Influence of oxygen ion implantation on the free volume parameters and electrical conductivity of a polymer-based bakelite RPC detector material

We have investigated the effect of ion implantation on structural modification and the electrical conductivity of Bakelite-resistive plate chamber (RPC) detector material used in high energy physics experiments. Samples of Bakelite polymer were exposed to 100 keV and 150 keV oxygen ions in the fluence of 1012 to 1015 ions cm−2. Ion implantation induced microstructural changes have been studied using positron annihilation lifetime spectroscopy, X-ray diffraction and Fourier transform infrared techniques. Positron lifetime parameters viz., o-Ps lifetime and its intensity showed formation of radicals, secondary ions due to the creation of interior tracks by high-energy ions followed by chain scission at lower fluence of 100 keV implantation. The decreased free volume size at 150 keV ion implantation is an indication of crosslinking and filling up of interior tracks by the implanted ions. Variation of ac conductivity with frequency obeys Jonscher power law at 100 keV and the conduction mechanism is explained by barrier hopping model. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44962.