“Characterization of polymeric composites by using positron annihilation spectroscopy”

Abstract

Over the past few decades, solid polymer electrolytes have received considerable attention due to their potential applications in solid state electrochemical devices like rechargeable batteries, super capacitors, fuel cells and chemical sensors. The present study is concerned with the effect of addition of LiClO4 on the structural, thermal, electrical and optical properties of PVC-co-PVAc / LiClO4 polymer electrolytes. The positron annihilation spectroscopy has been applied to investigate microstructural properties of the studied composites. The results of PAL and DBAR are employed to investigate the effect of addition LiClO4 on the free volume holes in PVC-co-PVAc / LiClO4 SPE system and discussed in relation to the observed changes in ionic conductivity, dielectric parameters and optical properties. The results obtained may be summarized as follows: The variations in τ3 and I3(%) as a function of LiClO4 concentration gives information about the manner at which the dopant affects the free volume hole size and concentration. Doping the polymer matrix with (Li+) and (ClO4−) ions occupy the free volume of smaller size present in the composite at initial doping level and hence reflects the constant at initial doping stage. At higher doping level, Li+ ions or molecules occupy the bigger size of free volumes. Therefore, the availability of free volumes in the composite reduces which reflects a drop in