Data underlying the publication: Healable Reversible Underwater Adhesives

The strategies used by organisms living in water to adhere to surfaces have been a major source of inspiration to develop synthetic underwater adhesives. Amongst the mechanisms explored, byssus-inspired organometallic chemistry offers a broad range of possibilities due to the breath of coordination bonds, salts and polymer backbones available. This has led to a significant amount of research on bio-inspired synthetic glue-type (liquid) and tape-type (solid) adhesives. However, reversibility under water, durability and universality of adhesion remains elusive. We demonstrate that the combination of Ni-organometallic chemistry with a flexible hydrophobic polymer allows developing fully healable and recyclable polymers able to reversibly adhere (under water) to substrates with surface energies as diverse as Teflon and glass. Other metal ions such as Fe3+ and Zn2+ did not provide the desired adhesion in water. The underlying mechanism is attributed to local water-induced chain re-orientation and the use of strong but dynamic organometallic coordination (Ni2+-2,5 thiophenedicarboxyaldehyde). The results unveil a versatile route to develop solid-state underwater adhesives and water-triggered healing polymers using a one-pot synthesis strategy (Schiff-base with metal coordination) with an underlying mechanism that can be extrapolated to different application domains such as biomedical, energy and underwater soft robotics.

水生生物附着于固体表面的策略，一直是开发合成水下胶粘剂的重要灵感来源。在已探索的各类附着机制中，受贻贝足丝（byssus）启发的有机金属化学（organometallic chemistry），凭借可获取的配位键、盐类与聚合物骨架的丰富选择，提供了大量开发可能性。这使得仿生合成胶状（液态）与带状（固态）胶粘剂领域涌现出大量研究成果。然而，粘附的水下可逆性、耐久性与通用性仍难以实现。本研究证明，将镍基有机金属化学与柔性疏水聚合物相结合，可制备出可完全自愈且可回收的聚合物材料，该材料能够在水下可逆地粘附于表面能差异极大的基底，如特氟龙（Teflon）与玻璃。其他金属离子如三价铁离子(Fe³+)与二价锌离子(Zn²+)则无法在水中实现预期的粘附效果。其背后的机制可归因于局部水诱导的分子链重取向，以及强而动态的有机金属配位作用（二价镍离子-2,5-噻吩二甲醛，Ni²+-2,5 thiophenedicarboxyaldehyde）。本研究结果揭示了一条通用的研发路径：通过一锅合成法（one-pot synthesis），即带有金属配位的希夫碱（Schiff-base）反应，制备固态水下胶粘剂与水触发自愈聚合物，其背后的机制可推广至生物医学、能源、水下软体机器人等多个应用领域。