Permanently Mechanically Adjustable Photothermal Catalytic Spontaneous Double Cross-Linking Network Enables Durable and Stretchable Plant Skin-Like Materials

In cellulose-based plastics, as a type of thermoplastic and thermosetting materials, the excellent balance of mechanical strength and ductility poses a large challenge. To tackle this problem, a novel approach is devised to introduce reversible non-covalent ester cross-linking into dynamic covalent hydrogen-bonded polymer networks. However, the formation of ester bonds typically requires excess reactants and dehydrating agents, which is energy-intensive, environmentally harmful, and costly. To address these concerns, inspired by polyester-rich plant bark, a supramolecular composite material is developed. It can be dissolved and regenerated using a binary solvent system (choline hexanoate/choline chloride-oxalic acid). In water, this supramolecular composite material underwent self-healing and ester exchange reactions to form double-cross-linked networks, interfaced with photo-thermal catalysis promoting the reaction due to its high photo-thermal conversion efficiency (86.7%) and water evaporation rate (1.38 kg m −2 h −1 ). This enables the rapid and repeatable construction of durable and stretchable biomaterials. The mechanical properties of the supramolecular plastic can be adjusted by solar photo-thermal conditions of the synthesis environment. These materials exhibit high performance in solar water evaporation and have self-healing properties and are degradable, recyclable, and capable of eliminating their own adhesions.