Photomechanical crystals composed of three-dimensionally ordered and densely packed photochromes hold promise for high-performance photochemical actuators. However, bulk crystals with high structural ordering are severely limited in their flexibility, resulting in poor processibility and a tendency to fragment upon light exposure, while previous nano- or micro-crystalline composites have lacked global alignment. Here, we demonstrate a photon-fueled macroscopic actuator consisting of diarylethene microcrystals in a polyethylene terephthalate (PETE) host matrix. These microcrystals survive large deformations and show a high degree of three-dimensional ordering dictated by the anisotropic PETE, which critically also has similar stiffness. Overall, these ordered and compliant composites exhibit rapid response times, sustain performance over at least hundreds of cycles, and generate work densities exceeding those of single crystals. Our composites represent the state-of-the-art for photochemical actuators and enable properties unattainable by single crystals, such as controllable, reversible and abrupt jumping (photosalient behavior).

Authors: Wenwen Xu (University of Colorado Boulder), David M. Sanchez (Stanford University), Umberto Raucci (Stanford University), Hantao Zhou (University of Colorado Boulder), Xinning Dong (University of California, Riverside), Mingqiu Hu (University of Massachusetts Amherst), Christopher J. Bardeen (University of California, Riverside), Todd J. Martinez (Stanford University), Ryan C. Hayward (University of Colorado Boulder)