A facile strategy to design shape memory rubber composites with tunable mechanical properties and photothermal performance

Shape memory polymers (SMPs) represent a prominent category of smart polymers that show attractive prospects in emerging fields of soft robots and biomedical devices. However, most of the existing SMPs show limitations in single-stimulus responsiveness and an imbalance between mechanical and shape memory properties. Herein, biological phytic acid served as a natural curing agent to vulcanize the biobased epoxidized natural rubber (ENR), while Fe3+ was introduced to construct a second cross-linked network based on coordination interaction. Polycaprolactone (PCL) was introduced and acted as net points to regulate the shape fixing behavior, while the dual cross-linked network provided strong resilience to achieve the shape recovery performance. Meanwhile, the Fe3+-based coordination complex not only served as sacrificial elements to realize tunable mechanical properties by effectively dissipating energy, but also acted as a photothermal agent to realize the light-induced shape memory behavior and thermoelectric power generation. The fabricated composites process multi-stimuli-responsive shape memory properties, photothermal capabilities, and tunable mechanical properties, exhibiting outstanding potential in harvesting sunlight for outdoor portable power generation and stimuli-responsive sensors.