Photo‐Tunable Elastomers Enabling Reversible, Broad‐Range Modulation of Mechanical Properties Via Dynamic Covalent Crosslinkers

Modulating the mechanical properties of soft materials with light is essential for achieving customizable functionalities. However, existing photo-responsive materials suffer from limited mechanical performance and a restricted tunable range. Here, a photo-tunable elastomer is developed by incorporating a urethane acrylate network with selenosulfide-based dynamic covalent crosslinkers, achieving high tensile strength exceeding 1.2 MPa in their stiff state and variable Young's modulus within a 0.8 MPa range. These crosslinkers undergo selenosulfide photo-metathesis, gradually breaking under ultraviolet light and reforming under visible light, enabling fine control over the modulus, strength, and stretchability of the elastomer. In terms of controllability, the design supports multiple tunable states, which allow for the use of intermediate mechanical properties. Moreover, by modeling the …