Design of mechanically robust, recyclable, multi-stimuli-responsive shape memory elastomers based on biological phytic acid and cuttlefish ink

Facilitating the utilization of biomass in the rubber field is a facile strategy to reduce environmental pollution and the carbon emission. Herein, biological phytic acid (PA) was served as an eco-friendly curing agent, and cuttlefish ink (CI) was acted as a photothermal trigger switch to fabricate multi-stimuli-responsive shape memory biobased epoxidized natural rubber (ENR) with mechanical robustness and recyclable ability. ENR was vulcanized by PA via the ring-opening reaction between phosphate groups of PA and epoxy group of ENR, leading to the construction of an impeccable cross-linking network and an adjustable T g gradient, which endowed the elastomers with improved mechanical properties and shape memory effect. Meanwhile, the topology rearrangement occurred at elevated temperatures relied on phosphate transesterification, leading to excellent thermo-activated recyclable ability and reconfigurable shape memory performance of the elastomers. Additionally, CI acted as reinforced filler to enhance the ENR matrix, enabling elastomers to achieve a robust tensile strength of 21.4 MPa and tensile toughness of 30.4 MJ/m 3 , which was nearly 26.8 times and 11.3 times of the neat ENR, respectively. Exhilaratingly, CI also acted as photothermal trigger switch for the response to near-infrared light and sun, which realized the remotely multistage shape memory performance, demonstrating the potential application of ENR in the field of actuators without environmental pollution.