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.