Supramolecular Solvent-mediated Polymeric Gel with High Adhesion and Toughness for Adaptive Grasping Soft Robotics

Glassy polymers such as polyacrylic acid suffer from fragility, limited extensibility, and toughness. By introducing solvents that weaken polymer-polymer interactions, glassy polymers can be converted into soft states. To obtain mechanical strength and ductility simultaneously, a supramolecular solvent-mediated polymeric gel with high toughness and adhesion is proposed by the synergistic effect of supramolecular solvent and polyacrylic acid. Polymerization of acrylic acid within the supramolecular solvent composed of β-cyclodextrin and citric acid results in a macroscopically homogeneous system with in-situ microphase separation: the polymer-rich phase exhibits compelling high elastic behavior under tensile strain, and the supramolecular solvent-rich phase weakens interchain interactions within polymer chains and establishes a robust solvent-polymer interface interaction, improving the toughness. The supramolecular solvent-mediated polymeric gels exhibit high toughness (208 MJ m⁻³), high stretchability (≈3400%), self-healing, and recyclability. The dynamic feature and strong affinity of supramolecular solvent would enable them to adaptively wet rough surfaces and form topological cross–linking for adhesion, thereby improving the interfacial toughness. Reversible adhesion could be realized by moisture treatment. The application of adaptive grasping soft robotics with in-situ repair capability is also demonstrated. This work provides a novel and simple strategy for the fabrication of tough gels with excellent adhesive performance.