Mechanical response of 2D polymer networks: role of topology, rate dependence and damage accumulation

The skeleton of many natural and artificial soft materials can be abstracted as networks of fibers/ polymers interacting in a non-linear fashion. Here we present a numerical model for networks of nonlinear elastic polymer chains with rate dependent crosslinkers similar to what is found in gels. The model combines the work-like chain models at the chain level with the transition state theory for bond dynamics.We study the damage evolution and the force displacement response of these networks under uniaxial stretching for di erent loading rates, network topology, and crosslinking density. Our results suggest a complex nonmonotonic response as the loading rate or the crosslinking density increases. We discuss this in terms of the microscopic deformation mechanisms and suggest a novel framework for increasing toughness and ductility of polymer networks using a bio-inspired Sacrificial bonds and Hidden Length (SBHL) mechanism. This works highlights the role of local network characteristics on macroscopic mechanical observables and opens new pathways for designing tough
polymer networks.