Bioinspired design of vascular artificial muscle

Recently, liquid crystal elastomers (LCEs) have drawn much attention for its wide applications as artificial muscle in soft robotics, wearable devices and biomedical engineering. One commonly-adopted way to trigger deformation of LCEs is using embedded heating elements such as resistance heating wires and photo-thermal particles. To enable the material to recover to its unactuated state, passive and external cooling is often employed to lower down the temperature, which is typically slow and environmentally sensitive. Here, inspired by biology, we design and fabricate a vascular LCE-based artificial muscle (VLAM) with internal fluidic channel in which we inject hot or cool water to heat up or cool down the material to achieve fast actuation as well as recovery. We demonstrate that the actuation stress, strain and cyclic response rate of the VLAM are comparable to mammalian skeletal muscle. Because of the internal heating and cooling mechanism, VLAM shows very robust actuating performance within wide range of environmental temperature.