Bio-mimicking hybrid polymer architectures as adhesion promoters for low and high surface energy substrates

Abstract Thermoplastic materials like High Density Polyethylene (HDPE) and Polytetrafluoroethylene (PTFE) are promising candidates for specialty industry/aerospace sectors considering their exceptional properties and lower densities. However, the low surface energy leading to poor wetting and reduced adhesion curtails the scope of their wide-spread usage. In this work, we report adhesion promoter primers based on epoxy–catechol with and without fluorinated polymer and investigated their adhesion promotion efficiency on low/high surface energy substrates. The rational design of catechol-fluorine-epoxy hybrid network, mimicking mussel chemistry enabled a non-destructive surface activating approach resulting in profound adhesion promotion. The fluorine containing primer could effectively enhance adhesion between homo and hetero interfaces of Aluminium/HDPE/PTFE owing to the good interface interaction and could outperform common etching methods. A series of molecular level characterizations together with computational and AFM studies provided evidences for the high degree of interaction of the primer between the substrates and epoxy-based adhesives. Bond integrity endurance test using a weight of 10 and 20 kg resulted in ‘no fail’ categorization for the primed substrates during the entire 40 days test duration. The catechol-functionalized primers reported here can be a good overreaching approach to keep non-polar substrates afloat in advanced sectors.