Mussel-inspired catechol prepolymers as surface primer for enhanced interface bonding to high-performance thermoplastics

High-performance thermoplastics , such as polyether ether ketone (PEEK) and polyester sulfone (PES), are extensively utilized across various industries owing to their exceptional properties. However, their relatively low surface energy often leads to insufficient bonding strength when adhering PEEK or PES. Commonly used surface pretreatments, such as acid-base and plasma treatments, have drawbacks including the use of toxic acids and bases, complex procedures, and poor stability. In this study, we synthesized four catechol-functionalized prepolymers by reacting bisquinone A with dithiols or diamines in a 1:1 M ratio. These catechol-containing prepolymers were employed as surface primers, and the adhesion performance before and after primer treatment was examined using epoxy adhesive for bonding tests. Compared to untreated samples, the lap shear strengths of surface primed PEEK and PES were significantly enhanced by 181 % and 114 %, respectively. These results indicate that the synthesized prepolymers with catechol structures can effectively serve as adhesive primers for bonding.