Nano-Sized rGO-Encapsulated TiO₂ Nanowire-Filled PDMS cone type dielectric elastomer actuator operating at low applied electric field

Dielectric elastomer actuators (DEAs) have versatile applications in soft robotics, medical devices, and environmental monitoring, making them a highly anticipated area for future applications. On the other hand, developing DEAs exhibiting high strain at low voltages remains challenging. This paper reports a strategy for enhancing the actuating performance of polydimethylsiloxane (PDMS) at low voltages by preparing a hybrid filler comprised of TiO₂ nanowires (TiO₂ NWs), polydopamine (PDA), and nano-sized reduced graphene oxide (nrGO). This hybrid filler, merging the virtues of these three materials, was added at 15 parts per hundred of rubber (phr), resulting in a 2.3-fold increase in the dielectric permittivity of PDMS while mitigating the increase in loss tangent and enhancing efficiency. Actuators fabricated using this composite exhibited the highest deformation at 10 phr, reaching approximately 27.31 % (at 28 V/µm), representing a remarkable 15.2-fold improvement compared to pure PDMS. Moreover, even at a low voltage of 1.6 V/µm, they displayed a substantial actuated strain of 2 %. This novel strategy for manufacturing hybrid fillers is a promising example of enhancing the performance of DEAs, offering innovative solutions for future technological advancements.