Liquid Crystal Elastomer based artificial neuromuscular unit with electrically controllable ultrafast actuation

Neuromuscular unit is the basic block for animals to convert their intentions into real movements. The similarity between ionic signal of action potential and electronic signal of electric circuit lures people to build an electronically controllable soft actuating system to rebuild the neuromuscular unit. Our work provides a new solution with a stretchable ultrathin gold-sputtered liquid crystal elastomer (LCE) film as artificial muscle which can be actuated by short voltage pulses (< 5ms) just like action potentials. Its actuation frequency range can cover the natural frequency of the mechanical system it is actuating. Therefore, it can amplify the output power density through resonance. Such energy-favorable amplification strategy is commonly used in animals’ locomotion and many robotic designs. During test, our artificial muscle (self-weight of 1.2 mg) can lift a weight of 3.1 g with actuation strain of 25% (peak strain rate of 400%/s) and frequency of 6 Hz. The power density of LCE artificial muscle in this case is 1300 W/kg, which outperforms most of the biological muscles. We believe such electrically controllable artificial neuromuscular system can inspire many new designs in the future.