Dynamic Non-Covalent Bonds Powering Enhanced Temporary Shape Retention Temperature and Mechanical Robustness in Shape Memory Polyurethane

Shape memory polyurethane (SMPU) with excellent mechanical
properties holds significant application value in engineering. However, achieving
high strength and toughness typically relies on hydrogen bonding for energy
dissipation, which limits the application of such PUs due to their deformation
temperature being below room temperature. Here, we introduce a rigid long-chain
polyamide acid with a rich aromatic structure as a chain extender, combined with
metal coordination, to develop a shape memory polyurethane with a phase
transition temperature of 50 °C and outstanding mechanical performance. The
presence of rigid segments of polyamic acid (PAA) and −COOH not only
increases the rigidity of the polyurethane chains but also promotes the formation
of hydrogen bonds and π−π conjugation, leading to physical cross-linking points
and significant microphase separation, resulting in superior mechanical properties
for PU-PAA. The dynamic bonding characteristics impart self-healing and solvent
recyclability to PU-PAA. The coordination interactions enhance the cross-linking points, enabling PU-PAA-Eu to exhibit excellent
shape fixation and recovery rates, as well as fluorescence properties. Additionally, due to the presence of −COOH, PU-PAA
demonstrates remarkable adhesion to various metals. This work provides a strategy toward the development of high performance
SMPU and holds promising potential for applications such as anticounterfeit coatings.