Exploration of free volume behavior and ionic conductivity of PVA: x (x = 0, Y2O3, ZrO2, YSZ) ion-oxide conducting polymer ceramic composites

Abstract

This article presents a comparative analysis of three distinct zirconia-inserted polyvinyl alcohol (PVA) polymer matrices. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) were used for the study of structural, chemical composition (functional groups), and morphological properties. Changes in IR bands revealed the interaction of nanofillers with the PVA matrix. ZrO2 added sample shows the lowest degree of crystallinity with the least free volume compared to pristine PVA. Threadlike chains and scattershot crystal morphologies were seen in AFM images, and the PVA/ZrO2 has the lowest level of roughness (1.27 nm). Positron annihilation lifetime profile showed identical behavior for τ3, τ2, and their intensities I3,I2. ZrO2 nanoparticles had a better interfacial interaction with the PVA matrix, which resulted in a higher Tg and shorter o-Ps lifetime (τ3). The positron trapping rate increased for ZrO2/PVA polymer ceramic composite (PCC), which indicated that both volume expansion and vacancy trapping effects occur when the positrons are effectively trapped at vacancies. The Nyquist plot for dielectric measurement was investigated, and an equivalent circuit model was used to evaluate variables such as carrier concentration (n), mobility (μ), and diffusion coefficient/ diffusivity (D). Ionic conductivity of 2.77 × 10−7 S cm−1 was recorded for the ZrO2/PVA sample. This might be due to a change (increase) in the carrier concentration.