Micromechanism-based chemo-mechanical cohesive model for polymer interface under transient chemical mass diffusion

This paper presents a fully coupled thermodynamically consistent chemo-mechanical cohesive zone model for polymer interfaces subjected to a chemo-mechanical environment. A bond-chain-interface method is exploited to describe the macroscopically interfacial performances controlled by the chemical reaction extent and the microscopic properties of interface. The energetics of bond stretching and the coupling between reactive-diffusive mechanisms and mechanics at the polymer interface are taken into account. The cohesive zone model is implemented using finite element method software ABAQUS through UEL subroutines. The numerical simulation with the cohesive element is directly compared to a single lap shear experiment for chemo-mechanical fracture of a bio-inspired polymer interface. Besides, a particularly numerical example including the chemical diffusion and compression case is conducted, it clearly shows the proposed model can capture the features of shear flux and stress-driven diffusion, which verifies the completeness of the chemo-mechanical interface theory. Finally, a parametric analysis is conducted to assess the influences of critical bond stretch, areal chain density and chemical reaction rate on the evolution of interfacial damage and rate of chemical diffusion. The model also accounts for the phenomenon where a strong polymer interface effectively restricts chemical diffusion across an interface. This research provides a novel investigative tool to study chemo-mechanical fracture of polymer interfaces, with potential applications in materials science and engineering.