Physical properties and β-phase increment of AgNO3-filled poly(vinylidene fluoride) films

X-ray diffraction (XRD), infrared (IR) transmition and optical absorption (OA) spectra, differential thermal analysis (DTA), dc electrical resistivity (ρ), magnetic susceptibility (χ) and electron spin resonance (ESR) of AgNO₃-filled poly(vinylidene fluoride) (PVDF) films, were measured over the filler mass fraction range 0.001 ≤ W ≤ 15%. XRD and IR analysis evidenced the increase of α- and β-PVDF crystalline phases due to the AgNO₃ filler. The maximum crystallinity increment was found at W = 0.5%. Three endothermic peaks were detected by DTA, and were attributed subsequently to: the first order para–para-electric phase transition, the first-order ferro-para-electric phase transition and the melting. The melting peak was used to calculate the order of reaction and the activation energy of melting. The observed OA peaks and/or plateau were attributed to the charge-transfer complex formed mainly by the AgNO₃ filler. This assumption was supported by the diamagnetic susceptibility detected for the present system. The temperature dependence of ρ was explored according to a previously proposed one-dimensional interpolaron-hopping model. The hopping distance was formulated numerically as a function of temperature and filling level. The ESR findings were attributed to the roles of AgNO₃ and dimethylformamide solvent in complex formation. Copyright © 2004 Society of Chemical Industry