Mechano-Optical Sensors Fabricated with Multilayered Liquid Crystal Elastomers Exhibiting Tunable Deformation Recovery

Advances in tuning the mechanoresponsive behavior of liquid crystal elastomers have facilitated the development of next-generation applications such as reconfigurable photonic/electronic materials, energy-harvesting devices, and flexible sensors. However, the molecular-level control of mechanical responses remains difficult, with limited tunability achieved for recovery processes after stimulus removal. Herein, a design concept is proposed for facilely tuning the recovery of both the macroscopic deformation and molecular orientation change of liquid crystal elastomers using layered materials that exhibit the desired mechanoresponsive behavior. Changing the layering materials (a polydimethylsiloxane film with elastic response to a polymethylpenten film with plastic response) alters the relaxation time from 6 months. To demonstrate this concept, highly sensitive, stretchable mechano-optical sensors with fast and ultraslow recovery times are developed that enable an applied strain to be quantitatively detected in real time or memorized with high spatial resolution, even with a conventional camera. This material design concept for arbitrarily controlling the recovery response can provide a platform for stimuli-responsive applications.