Designer Adhesives for Tough and Durable Interfaces in High-Performance Ti-Carbon PEKK Hybrid Joints

Advanced high-performance structural applications require the right materials in the right place and suitable interface engineering. However, poor adhesion in harsh environmental conditions frequently challenge material interfaces. An example is the moisture sensitivity of titanium-poly ether ketone ketone (PEKK) interfaces. Here, this work offers a high-performance composite adhesive system, which combines strong adhesion and high interfacial toughness, particularly when used in metal-polymer bonding. This system includes aminopropyl triethoxy silane (APTES)-polydopamine (SiPDA) layers, which can be formed on the titanium surface before the joining process with carbon fiber-reinforced PEKK (C/PEKK). Adhesion between PEKK and titanium is evaluated before and after hot/wet conditioning using mandrel peel tests. This work discovers that applying thin SiPDA layers not only results in a remarkable rise in the interfacial fracture toughness but also provides durable bond stability after hot/wet conditioning. These findings indicate that polydopamine-based coatings show great potential to achieve stable interfaces for the next generation of high-performance metal-polymer hybrid materials.