Internal and active heating and cooling systems in LCEs. (A) Introducing the microfluidic channel. The LCE actuator containing a microfluidic channel can produce fast actuation and recovery by alternately injecting hot water (90°C) and cold water (20°C). Reprinted with permission from Ref [124]. (B) Integrating thermal electric device. When a current is applied to a soft TED, the right side of the LCE contracts due to the heating by the Peltier effect, causing the TED-LCE to bend uniformly in the counterclockwise direction. Reversing the flow of current causes the previously heated right side to actively cool, and the left side of the device to heat up, resulting in a clockwise bending. Reprinted with permission from Ref [125].