Soft Actuators Based on Liquid Crystal Elastomer and Laser Induced Graphene

Thermoresponsive Liquid Crystal Elastomers (LCEs) are widely studied for their use as soft actuators as they feature excellent actuation properties including large actuation strains and reversible actuation processes. To overcome the prevalent limitations of rigid heating elements hindering the actuation performance of soft actuators, composites of LCEs and a soft heating structure promise a great enhancement of the actuation behaviour. As compliant heating elements conductive tracks of Laser Induced Graphene (LIG) are used which are obtained from laser scribing with an IR CO₂ laser on a polymeric precursor substrate. The precursor is converted into a conductive porous carbon thanks to a photothermal pyrolysis process. By embedding these conductive LIG tracks in a thermoresponsive LCE matrix a temperature sensitive soft actuator was built in which the LIG served as a Joule heating element to resistively heat the LCE and trigger an actuation. The actuation performance of the LCE and the LCE/LIG composite were investigated regarding actuation strain and stress and a demonstrator was produced.