Synergistic effects of nanosecond pulse laser and atmospheric plasma treatments on enhancing the interface fatigue performance of PA11-CFRP in type IV hydrogen storage tanks

The development of Type IV high-pressure hydrogen storage tanks faces persistent technical challenges, particularly in preventing the structural degradation of polymer liners. During operational cycles, repeated hydrogen filling and degassing processes impose severe interfacial fatigue on the bond between the thermoplastic liner and the carbon fiber-reinforced polymer (CFRP) composite overwrap. Improving adhesion integrity at the PA11-CFRP interface is critical for mitigating the risks associated with liner rupture. To address this challenge, a synergistic surface modification strategy for PA11 liners combining laser texturing with plasma activation was implemented. The interfacial fatigue performance was quantitatively evaluated via flatwise tensile (FWT) testing, incorporating S–N curve analysis and progressive stiffness degradation metrics. Notably, the laser-plasma co-treatment significantly improved the interfacial fatigue resistance of PA11-CFRP compared to untreated controls or individually modified surfaces, such as laser-only or plasma-only treatments. The underlying mechanism governing interface bonding durability was explored through multiscale characterization, including microstructural evolution at the PA11-CFRP interface, surface topography and roughness parameters, thermodynamic surface energy components, and chemical functionalities of activated interfacial groups. These findings establish a theoretical foundation for analyzing interface fatigue failures in large-scale applications of Type IV hydrogen storage tanks.