Superelastic and Photomechanical Behavior of Acylhydrazone Derivative Crystals

Abstract

The discovery of superelastic organic crystals capable of phototwisting and photobending represents a significant advance in the field of light-responsive materials. This research focused on the synthesis and characterization of crystals derived from trifluoromethyl-substituted acylhydrazone derivatives, known as TBMP. These crystals exhibited remarkable superelasticity when subjected to mechanical forces along their (010) crystallographic plane while showing a tendency to fracture along the (001) plane. Single-crystal analysis revealed that hydrogen bonds, especially C–H···F, C–H···O, and C–H···N interactions, are crucial in providing the crystals with superelastic properties. In addition, reversible E ↔ Z isomerization of TBMP molecules occurred under UV irradiation and heating, resulting in photomechanical (twisting or bending) and thermal recovery behavior of the crystals. Due to their exceptional properties, these crystals possess significant potential for application in robotic arm technology.