Data underlying the publication: Water-triggered self-healing and reversible underwater adhesion in metalorganic polymers

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.

水生生物的表面附着策略，是合成水下胶粘剂研发的重要灵感源泉。在已探索的诸多附着机制中，受足丝（byssus）启发的有机金属化学（organometallic chemistry），因可利用的配位键（coordination bonds）、盐类与聚合物骨架（polymer backbones）种类繁多，展现出广阔的应用潜力。这推动了大量关于仿生合成胶状（液态）与带状（固态）胶粘剂的研究工作。然而，水下可逆性、粘接耐久性及粘接普适性仍属尚未攻克的难题。本研究证明，将镍基有机金属化学（Ni-organometallic chemistry）与柔性疏水聚合物（hydrophobic polymer）相结合，可制备出具备完全自愈与可回收性能的聚合物，该聚合物能够（在水下）可逆附着于表面能范围覆盖特氟龙（Teflon）与玻璃等多种材质的基底。Fe³+与Zn²+等其他金属离子则无法在水中实现预期的粘接效果。其核心机制可归因于水诱导的局部链重取向，以及采用了强而动态的有机金属配位作用（Ni²+-2,5-噻吩二甲醛）。本研究成果揭示了一条通用的研发路径：采用一锅合成法（one-pot synthesis，结合金属配位的希夫碱（Schiff-base）反应），即可制备固态水下胶粘剂与水触发自愈聚合物，其核心机制可推广至生物医学、能源及水下软体机器人等多个应用领域。