Dielectric Relaxation and Interfacial Polarization in Polystyrene/Rutile TiO 2 Nanocomposites: Interfacial Electronic Coupling and Structure–Property Relationships

ABSTRACT This study investigates dielectric relaxation and thermal degradation in PS/rutile TiO 2 nanocomposites. Films were fabricated via solution mixing and hot pressing, with 5 wt% loading identified as the optimal concentration for uniform dispersion. Impedance spectroscopy (90°C–150°C) revealed non‐Debye Maxwell‐Wagner‐Sillars (MWS) interfacial polarization, accurately captured by an equivalent circuit model ( χ 2 ≈ 4.95 × 10 −5 ). Arrhenius analysis yielded an interfacial hopping activation energy of 13.46 kJ/mol. Thermal analysis (DSC/TGA) showed increased glass transition temperatures ( T g ) and enhanced degradation stability. Kinetic modeling via the Coats‐Redfern method confirmed that TiO 2 incorporation elevates both the activation energy ( E a ) and Gibbs activation energy (Δ G ) for thermal breakdown. Raman spectroscopy identified local interactions between Ti 4+ sites and the polymer π‐system, suggesting that restricted segmental mobility at the interface governs both charge transport and thermal kinetics. This unified interfacial approach successfully explains the synergistic dielectric and thermal phenomena observed in the composite.