Designing Strong yet Tough, Multifunctional and Printable Dynamic Cross‐Linking Waterborne Polyurethane for Customizable Smart Soft Devices

Abstract Dynamic cross‐linking waterborne polyurethanes (DCWPU) are gaining increasing attention for their great potential in soft materials, flexible sensors, soft robotics, and bioelectronic devices. However, achieving a facile and straightforward design of strong yet tough, multifunctional, and printable DCWPU for customizable smart soft devices is still challenging in this field. Here, a simple and versatile visible‐light‐mediate in situ metal‐ligand coordination (VSMC) strategy is reported to fabricate high‐performance DCWPU. This photochemical strategy enables the rapid and controllable release of metal ions from ethylenediaminetetraacetic acid salts, orthogonally triggering classical radical polymerization. The resulting homogeneous metal‐coordinated network significantly enhances the stretching strain, stress, and toughness of DCWPU. The reversibility of coordination further imparts excellent shape memory, shape‐reconfigurable and self‐healing features to DCWPU when exposed to heat stimuli. Moreover, the efficient VSMC strategy greatly reduces the gelation time of DCWPU to under 5 s, which improves its printability for flexible structural design. Leveraging these advanced performances, the design and application of the DCWPU in customizable smart soft devices are demonstrated. This work is expected to open new avenues for the design and application of high‐performance DCWPU.