Magneto-induced self-stratifying liquid metal-elastomer composites with high thermal conductivity for soft actuator

Electrothermal actuators have attracted widespread interest owing to the potential in soft robotics, whereas the lower actuated voltage and higher thermal conductivity remain main challenges to enhance their electrothermal actuating performance. Here, we propose a one-step magnetically induced sedimentation method for fabricating self-stratifying PDMS/CI/LM (polydimethylsiloxane/carbonyl iron/liquid metal) film to improve the deficiencies. Ideally, the thermal conductivity of the hybrid film is increased by 2.3 times than pure PDMS film. Under low voltage (<3.5 V) stimulation, the hybrid film-based actuator can produce a maximum temperature of 120°C and bending curvature of 1.68 cm ⁻¹. Moreover, the special structure of the hybrid film can be further assembled to be a pressure/magnetic biresponsive sensor, which also can be applied as the “on-off” controller. Finally, the bionic frog tongue and portable tactile-activated gripper are fabricated, demonstrating that the developed electrothermal actuator possesses wide application potential in intelligent devices and bionic robots.