Liquid Crystalline Elastomer for Separate or Collective Sensing and Actuation Functions

A porous liquid crystalline elastomer actuator filled with an ionic liquid (PLCE-IL) is shown to exhibit the functions of two classes of materials: electrically responsive, deformable materials for sensing and soft active materials for stimuli-triggered actuation. On one hand, upon the order-disorder phase transition of aligned mesogens, PLCE-IL behaves like a typical actuator capable of reversible shape change and can be used to assemble light-fuelled soft robot. On the other hand, at temperatures below the phase transition, PLCE-IL is an elastomer that can sustain and sense large deformations of various modes as well as environmental condition changes by reporting the corresponding electrical resistance variation. The two distinguished functions can also be used collectively with PLCE-IL integrated in one device. This intelligent feature is demonstrated with an artificial arm. When the arm is manually powered to fold and unfold, the PLCE-IL strip serves as a deformation sensor; while when the manual power is not available, the role of the PLCE-IL strip is switched to an actuator that enables light-driven folding and unfolding of the arm. This study shows that electrically responsive LCEs are a potential materials platform that offers possibilities for merging deformable electronic and actuation applications.