Experimental and computational investigation of PVDF-BaTiO_3 interface for impact sensing and energy harvesting applications

摘要

The interfacial polarization between PVDF and BaTiO_3 was studied using density functional theory calculations and atomic charge density analysis. A comparative study of dielectric relaxation, thermodynamic properties and impact analysis of the electrospun polyvinylidene fluoride (PVDF) and a 3 % BaTiO_3-PVDF nanofibrous composite are presented. The frequency-dependent dielectric properties revealed the microstructural feature of the composite material. The impedance analysis and Nyquist plots showed a decrease in the bulk resistance of the composite compared to the pure PVDF. The temperature dependence of the electric modulus shows Arrhenius-type behavior. The electric loss modulus relaxation peak shifts towards the high frequency side which indicates a decrease in relaxation time and faster charge carrier dynamics. The observed non-Debye type dielectric relaxation in electric loss modulus follows a thermally activated process, which can be attributed to the polaron hopping effect. The particle-induced crystallization of the PVDF polymer is supported by thermodynamic properties from differential scanning calorimetric measurements. The observed increase in piezoelectric response from high strain rate impact sensing was attributed to the interfacial interaction between PVDF and BaTiO_3.