Dynamic Non-Covalent\nBonds Powering Enhanced Temporary\nShape Retention Temperature and Mechanical Robustness in Shape Memory\nPolyurethane

Shape memory polyurethane (SMPU) with excellent mechanical\nproperties\nholds significant application value in engineering. However, achieving\nhigh strength and toughness typically relies on hydrogen bonding for\nenergy dissipation, which limits the application of such PUs due to\ntheir deformation temperature being below room temperature. Here,\nwe introduce a rigid long-chain polyamide acid with a rich aromatic\nstructure as a chain extender, combined with metal coordination, to\ndevelop a shape memory polyurethane with a phase transition temperature\nof 50 °C and outstanding mechanical performance. The presence\nof rigid segments of polyamic acid (PAA) and −COOH not only\nincreases the rigidity of the polyurethane chains but also promotes\nthe formation of hydrogen bonds and π–π conjugation,\nleading to physical cross-linking points and significant microphase\nseparation, resulting in superior mechanical properties for PU-PAA.\nThe dynamic bonding characteristics impart self-healing and solvent\nrecyclability to PU-PAA. The coordination interactions enhance the\ncross-linking points, enabling PU-PAA-Eu to exhibit excellent shape\nfixation and recovery rates, as well as fluorescence properties. Additionally,\ndue to the presence of −COOH, PU-PAA demonstrates remarkable\nadhesion to various metals. This work provides a strategy toward the\ndevelopment of high performance SMPU and holds promising potential\nfor applications such as anticounterfeit coatings.