Intermolecular interactions and high dielectric energy storage density in poly(vinylidene fluoride-hexafluoropropylene)/poly(vinylidene fluoride) blend thin films

Homogeneous poly(vinylidene fluoride-hexafluoropropylene) and poly (vinylidene fluoride) (P(VDF-HFP)/PVDF) blend films were prepared via a chemical solution approach, followed by quenching, annealing, and hot pressing. The intermolecular interactions of the blends were investigated through atomic simulation. Higher melting temperature, higher crystallinity, larger elastic modulus, and improved breakdown strength (>850 MV/m) were observed in the optimized polymer blends, in comparison with either of the two constituent polymers, PVDF or P(VDF-HFP). In addition, the P(VDF-HFP)/PVDF blend film also showed larger dielectric constant. As a result, an extremely high energy density of 30.1 J/cm3 was achieved in P(VDF-HFP)/PVDF (50:50 by weight) blend films.