Fully Recyclable, Healable, Soft, and Stretchable Dynamic Polymers for Magnetic Soft Robots

Magnetic soft robots capable of wirelessly controlled programmable deformation and locomotion are desirable for diverse applications. Such multi-variable actuation ideally requires a polymer matrix with a well-defined range of softness and stretchability (Young's modulus of 0.1-10 MPa, high stretchability >200%). However, this defined mechanical range excludes most polymer candidates, leaving only a limited number of available polymers (e.g., PDMS, Ecoflex) with covalently cross-linked networks that may lead to non-recyclable robots and further potential threats to environment. Herein, based on the synergistic effects of reduced cross-linking density and intermolecular hydrogen bonding, a dynamic covalent polyimine is newly designed as polymer matrix and magnetic microparticles as fillers, and integrate defined softness and stretchability, full chemical recyclability, rapid room-temperature healability and multimodal actuation into a single magnetic soft robot. The polyimine is soft and stretchable enough to process soft robots in various geometries by simple laser cutting, without the need to pre-design the geometry to suit target scenarios. Through a cyclic depolymerization/repolymerization, this full recycling restores 100% of the robots' mechanical properties and rapid deformability/mobility to their original level within seconds and heals quickly within minutes when damaged, facilitating ideal cyclic material economy for soft robots in diverse scenarios.

Automated summary

Researchers have designed a new polymer matrix and magnetic microparticles to create a programmable magnetic soft robot capable of deformation and locomotion. The polymer has a defined range of softness and stretchability and allows for full chemical recyclability and rapid room-temperature healability. The robot's mechanical properties can be fully restored and its deformability/mobility can be healed quickly within seconds and minutes, respectively, through cyclic depolymerization/repolymerization.