Creating tough Mussel-Inspired underwater adhesives from plant catechyl lignin

The adoption of plant feedstocks to create mussel-inspired adhesives can considerably improve the sustainability and economic viability of such important materials. Catechyl lignin (C-lignin) is essentially a homogeneous and linear biopolymer, which can be depolymerized into a single catechol compound suitable for the fabrication of mussel-inspired materials. Here, we present a novel approach to engineering catechol-functionalized copolymers from C-lignin in Chinese tallow seed coats through depolymerization, derivatization, and copolymerization, where almost all atoms in C-lignin are incorporated into the final materials. The resulting mussel-inspired copolymers display outstanding adhesion on various surfaces, demonstrating strengths surpassing 2.0 MPa on hydrophobic PTFE and reaching 8.1 MPa when submerged in seawater on steel. This work pioneers a burgeoning paradigm for developing tough mussel-inspired underwater adhesives sustainably, potentially incentivizing advancements in the fabrication of functional materials.