Temperature-dependent dielectric and AC conductivity of zinc oxide nanoparticle-enhanced CMC/PEO matrices: Insights for functional applications

Metal oxide nanoparticles in polymers create versatile materials with superior chemical and physical properties, making them ideal for electronic applications. This study synthesized ZnO nanoparticle-polymer hybrid (ZNPH) films using a Carboxymethyl Cellulose (CMC)/Polyethylene Oxide (PEO) blend (70/30 wt ratio) and ZnO nanoparticles (ZnO NPs) prepared via the Sol-Gel method. The dielectric and AC conductivity of the films were evaluated across 10 Hz to 10 MHz and temperatures of 298–333 K. At F = 50 Hz, the dielectric constant (ε') of the CMC/PEO blend rose from 12.7 at 298 K to 1373.9 at 333 K, while 4 % ZnO NPs enhanced ε' to 65.2 at 298 K and 1922.4 at 333 K. Relaxation time (τ) significantly decreased from 82 µs to 1 µs for the CMC/PEO matrix and from 2.1 µs to 0.34 µs for ZNPH films in the same temperature range. Electrical conductivity (σ') improved, with CMC/PEO showing log(σ') = -6.11405 (σ' = 7.69E-7 Ω·m⁻¹) and 4 % ZnO NPs achieving log(σ') = -5.70849 (σ' = 1.96E-6 Ω·m⁻¹). Activation energy (Ea) decreased from 1.1 eV for CMC/PEO to 0.85 eV for ZNPH at F = 100 Hz. These findings demonstrate the enhanced dielectric, relaxation, and conductivity properties of ZNPH films, making them promising for energy storage and advanced dielectric applications under variable temperature conditions.