Mechanically Tunable Slide‐ring Polymers via Photo‐regulated Topological Control

Abstract

Post‐synthetic dynamic control of polymer topology to modulate material properties on demand remains a grand challenge in polymer science. Here, we demonstrate a light‐responsive slide‐ring polymer network whose mechanical properties can be reversibly tuned through photoisomerization of incorporated azobenzene units. In the trans‐state, azobenzene enables unhindered sliding of macrocycles along the polymer backbone, yielding a softer, more ductile material. UV‐induced switching to the sterically demanding cis‐configuration restricts ring mobility, thereby increasing the Young's modulus by two‐fold while reducing toughness. Control experiments with non‐interlocked analogs revealed the opposite mechanical response—light‐induced softening—highlighting the pivotal role of topology in property regulation. Furthermore, the azobenzene linkage confers controlled degradability under mild conditions. This work establishes a versatile strategy for post‐synthetic topological control via molecular photoswitches, enabling the design of adaptive polymers with stimuli‐responsive mechanical properties for applications in smart materials.