Effect of V2O5 incorporation on the Structural, Electrical, and Conduction Properties of sulfonated PVC/PMMA Blend: Positron Annihilation Study

Abstract

The present study investigates the structural, electrical, and free-volume properties of PVC/PMMA blends modified with V2O5 filler using various characterization techniques. X-ray diffraction (XRD) analysis reveals that the addition of V2O5 does not significantly alter the peak positions but decreases the intensity and broadens the peaks, indicating a slight decrease in the degree of crystallinity. The AC conductivity of the PVC/PMMA/V2O5 blend is lower compared to the PVC/PMMA blend, attributed to the dielectric properties of V2O5, which increase the overall dielectric constant and reduce the AC conductivity. The conduction mechanism is identified as the correlated barrier hopping (CBH) mechanism, where charge carriers require energy to travel through the material. Impedance spectroscopy shows a semicircle representing Debye relaxation, a constant phase element, and an inductive element. The DC ionic conductivity of the PVC/PMMA/V2O5 blend is lower than the PVC/PMMA blend, explained by strong interactions between V2O5 and polymer chains, restricting mobility and segmental motion essential for ionic transport. Positron annihilation lifetime spectroscopy (PALS) indicates that adding V2O5 decreases the average free volume size and increases the free volume fraction, attributed to the reinforcement effect of V2O5, which restricts segmental motion and alters free volume characteristics. The findings provide valuable insights into structure-property relationships in PVC/PMMA/V2O5 blends, with implications for designing advanced polymer-based materials with tailored electrical and free-volume properties for applications in energy storage, sensors, and optoelectronics.