Thermo- and near infrared light-induced reversible multi-shape memory materials for actuators and sensors

Smart materials with reversible shape transformation have drawn enormous interest for their potential applications in various fields. Herein, we show a novel reversible shape change bilayer material based on a shape memory polymer layer and a passive silicone layer, which can exhibit excellent thermo- and near infrared (NIR) light-induced reversible multi-shape memory performance. The NIR light responsiveness of the material is achieved by the introduction of tannic acid/ferric ion coordination, while the multi-shape memory effect originated from the wide glass transition temperature of the shape memory polymer layer. Based on the shape recovery stress at elevated temperature and resilience force of the silicone layer during the cooling process, thermo- and NIR light-induced reversible multi-shape memory performance is realized. Moreover, the practicability of the bilayer material as a light-driven actuator and temperature sensor is also investigated, demonstrating its versatile application potential as an actuator and sensor.