Deformation of Inhomogeneous End-linked Polymer Networks

Polymer networks represent an important class of soft materials with a broad range of applications in adhesives, coatings, membranes and natural materials. In particular, synthetic end-linked polymer gels, where the network is swollen in solvent, has received growing attention in the biomedical field due to their structural and mechanical similarities to tissues. Failure of these materials during mechanical deformations is intimately tied to their elastic and fracture properties. Synthetic and natural gels have highly complex environments that contain defects and phase boundaries, and the interplay between these molecular structures and the elastic and fracture responses remains an open question. In this study, we use molecular dynamics simulations to prepare and characterize two-phase polymer networks with one glassy and one rubbery domain. We characterize their mechanical properties and how the strain localizes in the glassy and rubbery domains as a function of the polymer chain length. Our simulations reveal that structural features on multiple length-scales serve to localize the site of failure.