Shape Memory Elastomers: A Review of Molecular Structures, Stimulus Mechanisms, and Emerging Applications

Shape memory elastomers, a class of smart polymers, can remember their initial shapes under external stimuli and have potential applications in many fields, including medical devices, artificial muscles, actuators, and soft robots. Therefore, this review aims to explore research progress on the molecular structures, stimuli-responsive mechanisms, and emerging applications of shape memory elastomers and their composites in recent years. First, the molecular structures, shape memory effects, and working mechanisms of shape memory elastomers are thoroughly discussed and explained based on different external stimuli, including heat, light, electricity, magnetic fields, and solvents. Subsequently, emerging applications of shape memory elastomers, such as artificial muscles, actuators, soft robots, smart electronics, and aerospace, are presented. Finally, future challenges and insights into shape memory elastomers are discussed. Shape memory elastomers have received extensive attention and show great application potential in many emerging fields.