Self-Reinforcing Poly(disulfides) Underwater Adhesives via Catechol-Cation Synergy.

Developing high-performance underwater adhesives capable of tolerating complex application scenarios while exhibiting specific degradability represents a critical yet highly challenging endeavor. Inspired by marine bio-adhesion, this work reports a catechol-ammonium cation synergistically reinforced poly-(disulfides) underwater adhesive, which demonstrates universal adhesion across diverse substrates and especially robust adhesion stability across a wide temperature range, spanning from -196 °C to 200 °Ca feature rarely reported in dynamic polymeric systems. Such exceptional stability is attributed to the synergistic integration of π-cation interactions, covalent crosslinking, and multiple hydrogen bonds in the cohesive network. More importantly, the adhesive exhibits self-reinforced in situ underwater adhesion, reaching a maximum strength of 7 MPa on glass substrates. This unique self-reinforcing behavior stems from the capacity of cationic amine groups to displace substrate hydration layers, thereby creating a dehydrated interface favorable for catechol-mediated binding. Meanwhile, the hydrophobic poly-(disulfides) backbone effectively impedes water penetration, endowing the adhesive with long-term underwater stability. Moreover, the inherently dynamic poly-(disulfides) backbone undergoes specific depolymerization in alkaline conditions, thereby expanding the potential applications of this high-performance, degradable underwater adhesive in complex aqueous and even marine environments.