Photoswitchable Flexible-Brittle Transition with Reversible Cracking and Healing in a Photochromic Crystal

Soft materials with ordered structures have attracted much attention due to their potential applications, such as flexible electronics, optical devices, and sensor materials. In particular, organic crystals that exhibit elastic and plastic deformation, as well as self-healing capability, are attractive owing to their shape adaptability and low cost. Although reversible photoinduced modulation of mechanical properties has been reported, organic crystals capable of repeated fracture and subsequent