When Polymers Part Ways: Modeling Mechanical Failure at Polymer-Polymer Interfaces

Polymeric encapsulants are essential materials in photovoltaic modules, protecting sensitive electronics from environmental factors while maintaining the mechanical stability of the assembly. However, these materials are vulnerable to degradation processes caused by environmental exposure, ultraviolet radiation, thermal stresses, and mechanical loading. As the market increasingly shifts to more cost-effective material choices, composite layered encapsulants made from ethylene-vinyl acetate (EVA) and polyethylene elastomer (POE) are becoming more popular. Despite their current adoption, there is uncertainty regarding the performance of multilayered EVA-POE-EVA (EPE) encapsulants as this usage is not supported by adequate reliability testing or field data. In this study, we utilize molecular dynamics simulations to investigate mechanical failure of EPE encapsulants. Our objective is to identify uncertainties related to the adhesion between polymer layers within EPE composites. This talk will address the non-trivial challenge of constructing an interpenetrating EVA-POE interface with control over interfacial geometry. We will report on simulations of mechanical testing used to predict stress-strain relationships and identify the impact of cross-link density, bond breaking frequency, and interfacial geometry.