Cooperative modification of PVDF electroactive films due to the exfoliated and oriented Na+‐MMT with assistance of different cationic chain length ionic liquids

Abstract

AbstractPoly(vinylidene fluoride) (PVDF) based nano dielectric composites have been investigated widely due to their potential application in sensors, actuators, and energy storage fields. To achieve these goals, a novel modification of PVDF electroactive films was prepared due to the exfoliated and oriented Na+‐MMT with the assistance of different cationic chain length imidazole‐based ionic liquids. The results proved the ion exchange between Na+‐MMT and ILs promoted exfoliation and uniform dispersion of Na+‐MMT in PVDF matrix efficiently even under a low ILs content (<0.05%). Furthermore, the existence of ILs and shearing force contributed to the oriented dispersion of Na+‐MMT. The synergistic effect of Na+‐MMT and ILs induced the crystal conformation transition from non‐polar α‐crystal to electroactive β/γ crystal. The ILs with longer cationic chains behaved much higher inducibility for PVDF electroactive phases. Compared with pure PVDF, PVDF/Na+‐MMT/ILs nanocomposites with longer cationic chain ILs showed higher dielectric constant, breakdown strength, and energy density, while kept low‐dielectric loss and conductivity. The improved compatibility between PVDF and Na+‐MMT due to the ion exchange and decreased crystal size for the polar β/γ crystal enhanced the transparency and elongation at break of PVDF/Na+‐MMT/ILs nanocomposites significantly. The results proved [C16MIM][Cl] behaved optimum synergistic modification effect for the nanocomposites, and which showed potential applications in dielectric energy storage and microelectronic fields.