Tailoring Photoweldable Shape Memory Polyurethane with Intrinsic Photothermal / Fluorescence Via Engineering Metal-Phenolic Systems

Multifunctional shape memory polymers are significant for next-generation intelligent systems as smart materials. However, their practical applications are limited by toughness, manufacturability, and functional integration strategies. Besides, while 4D printing is used to construct deformable devices, the limited accessible shapes and difficulty of integrating multiple materials hindered the development of multifunctional devices. Herein, metal-phenolic coordination is used as crosslinks to tailor tough shape memory polyurethanes with intrinsic photothermal effect and/or tunable fluorescence. The reversible dissociation of metal-phenolic complexes upon loading provides an efficient energy dissipation for the polymer network. The photothermal/fluorescent properties of target polyurethane can be effortlessly programmed by changing the coordinated metals and functional ligands. The obtained fluorescent polyurethane displays tunable fluorescence through the reversible dissociation-association of dynamic bonds upon thermal stimulus. Moreover, relying on light-triggered hybrid exchange reactions among various metal-phenolic coordination bonds, heterogeneous interfaces can be merged to manufacture exquisite 3D shape-shifting devices and integrate more advanced functions. As demonstrations, intrinsic photothermal-responsive shape memory stent, and 3D fluorescent encryption device are produced based on photo-welding instead of 4D printing. This study not only provides a convenient supramolecular strategy for constructing multifunctional smart materials but also demonstrates a feasible method for making personalized integrated architectures.