Bioinspired phenol-amine chemistry for developing bioadhesives based on biomineralized cellulose nanocrystals

Inspired by the phenol-amine chemistry and biomineralization of insect cuticles, we developed a green and facile strategy for preparing a bio-adhesive with excellent adhesion properties, mildew resistance, and antibacterial activity. This biomimetic strategy incorporates functional catechol-modified ε-polylysine and vanillin via grafting and Schiff base reactions. The biomineralized cellulose nanocrystals were prepared using a cellulose nanocrystal bio-template by regulating the in-situ biomineralization of inorganic nanoparticles, thereby building an optimized organic-inorganic mineralization framework in the polymer. The bonding strength of composite adhesive was significantly improved by multiple cross-linking networks through sacrificial hydrogen bonds, electrostatic interactions, and dynamic covalent bonds. The adhesion strength of the composite adhesive reached 1.13 MPa, which was 151% higher than the pristine adhesive. As a result of the synergistic effect of the catechol component, cationic ε-polylysine, and aldehyde group, the bio-adhesive also exhibited favorable anti-mildew and anti-bacterial properties.