Upon spontaneous deposition on surfaces underwater and moderate compression, single-component coacervates of adhesive peptide mimics (mfp-3S-pep) display orders of magnitude improvement compared with un-coacervated native (mfp-3S) or synthetic peptides. The increase in the work of adhesion is due to the peptide’s intrinsic cohesive properties upon coacervation correlated with dehydration, tight peptide packing and restricted peptide mobility.

Broader Impacts: Dense single-component coacervate liquids represent an essential adaptation for the priming stages of mussel adhesive deposition, and provide a previously untapped design principle for synthetic underwater adhesives.