Bioinspired Adhesives from Bio-Sourced Poly(amino acid)s Coacervates: Green and Tough

Green adhesives are gradually replacing traditional synthetic adhesives due to their eco-friendly properties and sustainability. However, the industrial applications of green adhesives are limited by their lower strength and higher cost. Here, inspired by sandcastle worms, we show green adhesives with combined high adhesive strength and low cost by enhancing the interaction of γ-PGA/ε-PLL coacervates through the introduction of tannic acid. The preparation method is green, simple, and fast. Specifically, taking advantage of non-covalent interactions between three components, the synergistical enhancement of cohesion and adhesion leads to the excellent adhesive strength, exhibiting a maximum adhesive strength of 18.21 MPa and an instant adhesive strength of 1.54 MPa. Notably, the non-covalent interactions endow the adhesive with reversible debonding-on-demand and recyclability, retaining its original adhesive strength even after 10 cycles. The feasibility to simultaneously overcome the major bottlenecks for green adhesives provides new insights for developing other sustainable green materials.