Making Protein-Based Adhesives Water Resistant: Role of Protein Water Solubility, Galloyl Modification, and Complexation

There has been an ongoing interest in using proteins as more environmentally friendly substitutes for the existing synthetic adhesives. Poor water resistance is a particular shortcoming of protein-based adhesives, which negatively affects their outdoor functionality. In this study, we systematically investigated if water solubility of the protein, addition of a phenolic compound such as tannic acid, and protein–polyphenol complexation could improve the water resistance of protein-based adhesives. It was found that the synergetic effects of these parameters can yield commercial-level water resistance.