Exploring the relationship of dielectric relaxation behavior and discharge efficiency of P(VDF-HFP)/PMMA blends by dielectric spectroscopy

The dielectric relaxations in P(VDF-HFP)/PMMA blends were investigated by dielectric relaxation spectroscopy. Various dielectric relaxation and their molecular mechanisms of P(VDF-HFP), PMMA, and P(VDF-HFP)/PMMA composite films were analyzed. According to the fitted data of the Havriliak-Negami (HN) function, all relaxation processes belong to non-debye relaxation, the activation energy (E _a), relaxation time (τ _HN) and dielectric relaxation strength (Δɛ) of P(VDF-HFP)/PMMA blends significantly decreased around and below room temperature with increasing PMMA content. But, the results of α _c relaxation are opposite. In addition, the conductivities (σ) of P(VDF-HFP)/PMMA composite films also sharply decreased with the addition of PMMA. Thus, the high discharge energy density and efficiency of dielectric materials closely related with the lower E _a, τ _HN, Δɛ and σ.