A study on electroactive PVDF/mica nanosheet composites with an enhanced γ-phase for capacitive and piezoelectric force sensing.

Herein, a multifunctional poly(vinylidene fluoride) (PVDF)/mica nanosheet composite (PMNC) thin film was developed for preparing a capacitive and piezoelectric force sensor. A high electroactive γ-phase content (89%) of PVDF was achieved through a facile rapid cooling process of PMNC films. The crystallinity of PVDF decreased upon the addition of mica nanosheets, while the dielectric constant increased significantly (∼300%). The capacitance-based PMNC pressure sensor was found to be sensitive to the applied pressure. On the other hand, piezoelectric voltages of 18 V (single layer) and 32 V (multi-layer) were generated for PMNCs loaded with 1% mica nanosheets. Furthermore, a PMNC based nanogenerator generated a power density of 8.8 µW cm-2 and showed excellent durability (>60 000 cycles). High flexibility, lightweight and skin-friendly PMNCs could be a potential material in applications such as energy harvesting, energy storage, actuators, and self-powered and smart wearable electronic devices.