Dielectric properties of PVA/FeGaInS₄ composites: effects of temperature and concentration of fillers.

This study investigates the dielectric behavior of polyvinyl alcohol (PVA) composites incorporating FeGaInS4 layered crystals as fillers at varying weight concentrations (1 wt.%, 3 wt.%, 5 wt.%, and 8 wt.%), synthesized using the solution mixing method. The layered structure of FeGaInS₄ facilitates distinctive interfacial interactions with the polymer matrix, potentially augmenting dielectric properties. Structural characterization was performed using X-ray diffractometry and Fourier-transform infrared (FTIR) spectroscopy, while dielectric properties were assessed via dielectric spectroscopy across different filler concentrations, temperatures, and frequencies of applied alternating current. FTIR analysis elucidated polymer-filler interactions, and dielectric spectroscopy results demonstrated an increase in dielectric permittivity with temperature and a decrease with frequency. Notably, the composite with 1 wt.% filler exhibited the highest dielectric permittivity, attributed to the uniform dispersion of FeGaInS₄ crystals within the matrix, enhancing interfacial polarization. The tangent loss angle was observed to rise with temperature, corresponding to increased electrical conductivity. The Correlated Barrier Hopping (CBH) model was applied to evaluate system parameters (s, WM, Rω, and N) for PVA and FeGaInS₄-based composites at 293 K and 313 K under a frequency of 2 × 103 Hz, indicating charge transport via electron hopping between localized states mediated by zone and hopping conductivity mechanisms. Activation energy values were determined for composites with varying filler concentrations, ranging from 0.71–0.30 eV for pure PVA to 1.46–0.85 eV (1 wt.%), 0.57–0.27 eV (3 wt.%), 0.71–0.30 eV (5 wt.%), and 0.70–0.34 eV (8 wt.%). The findings reveal that increasing the semiconductor filler content enhances electrical conductivity, underscoring the potential for optimizing the dielectric and electrical properties of PVA composites through controlled filler concentration. [ABSTRACT FROM AUTHOR]