CPBA/PVDF dielectric elastomer composites with high actuation performance under low electric field by optimizing the internal structure

Dielectric elastomers (DEs) have been extensively studied for their excellent electromechanical conversion properties, which make them ideal for flexible and non-magnetic drives. However, the common DEs usually require a high actuating electric field to achieve outstanding performance, severely limiting their application. In this study, advanced DE composites with good mechanical and dielectric properties was designed and synthesized (named as CPBA/PVDF). Adding DMF to the precursor solution and removing it after polymerization can lower the crosslinking density and increase linear polymer plasticizers in the matrix. As a result, the Young's modulus reduces and elongation at break arises without deteriorating the hysteretic and relaxation properties. Moreover, the incorporation of polar PVDF notably increases the tensile strength and dielectric constant of the composite films. Based on these, the CPBA/PVDF-3 gets a relatively high dielectric constant (5.74@1 kHz) and low modulus (0.144 Mpa), remarkably improves its actuation sensitivity (39.86), which is three times higher than that of the CPBA matrix (11.44). Therefore, CPBA/PVDF-3 achieved a high actuating strain of 25.1 % under 17.17 kV/mm with non pre-strain, and 160 % at 36.3 kV/mm under 200 % biaxial pre-tension. Importantly, it demonstrated a specific power density of 235 W/kg at just 16 kV/mm (@ 6 Hz). In addition, a simple linear actuator based on the CPBA/PVDF film can produce a free displacement of 0.755 mm (7.55 % of the actuator's effective length) and an output force of 306.95 mN/g at 15.7 kV/mm.