Robust mussel-inspired adhesives sourced from sustainable lignin

Adhesive materials resistant to manifold extreme conditions, such as water, organic solvents, and ultra-low temperatures, are highly sought after but remain rare. Here we present a top-down approach for making mussel-inspired, catechol-based copolymers from two types of natural plant lignins involving depolymerization, derivatization, and copolymerization. The lignin-sourced polymers exhibit robust adhesion and high resistance to water (8.73 MPa) and cryogenic temperature (7.28 MPa), and even retain 6.04 MPa after consecutive immersion in water and liquid N2, a testing condition rarely examined. Through a combination of monomer permutation screening and molecular dynamics simulations, we demonstrate that lignin-specific moieties, such as catechol, methoxy, and alkyl groups, significantly enhance the adhesive performance of the resulting polymers. Thus, this work pioneers a sustainable pathway for making robust biomimetic materials from bio-based feedstocks.