Study on the interfacial interactions and adhesion behaviors of various polymer-metal interfaces in nano molding

This study focuses on investigating interfacial interactions and the adhesion mechanism of polymer-metal interfaces in nano-molding. Polyphenylene sulfide (PPS), polyamide 6 (PA6), and isotactic polypropylene (iPP) were chosen as candidate polymers, and aluminum (Al), and copper (Cu) were used as metal substrates. By establishing the metal matrix composed of a rectangular pit with length, width, and depth of 4.5, 4.5, and 2.0 nm, respectively, six paired polymer-metal interfacial systems in a cuboid of 7.5 × 7.5 × 11.5 nm, consisting of metal, polymer, and vacuum layer (from bottom to top) were constructed. Molecular dynamics simulations were performed to calculate interfacial interactions and bonding processes. Results showed that wall-slip behavior was pronounced in nano-molding. Viscoelasticity and polarity of the polymers played a crucial role in interfacial interactions, which guided the wall-slip behavior and greatly affected the bolt performance. PA6 and PPS were more suitable for molding than iPP on both Al and Cu substrates. PA6 showed the best filling and bonding performances, followed by PPS, while iPP revealed the poorest performances. The Cu substrate exhibited better anchor strength and filling rate than Al substrates with the same polymer.