Azo-Functionalized Thermoplastic Polyurethane for Light-Driven Shape Memory Materials.

Shape memory polymers have great potential in the fields of soft robotics, injectable medical devices, and as essential materials for advanced electronic devices. Herein, light-triggered shape-memory thermoplastic polyurethane (TPU) is reported using azido TPU grafted by the photoswitchable azo compound. The trans-cis transitions of the azobenzene on the side chain of the TPU induce the recoiling of the main chain, leading to shaping memory behavior. Under UV irradiation, cis-azo allows the oriented main chain to recoil to release residual stress and realize light-triggered shape memory behavior. The facile method proposed here for the preparation of azo-functionalized TPU can provide viable opportunities for soft robotics and smart TPU applications.