Deformation of Hybrid Networks

Hybrid networks - networks consisting of different types of strands which could differ by their degree of polymerization (DP), chemical structure, and rigidity (Kuhn length). Examples of hybrid networks include biological networks and gels made by crosslinking biopolymers with various binding protein and networks made by crosslinking graft polymers through their side chains. Here we report on a theoretical model and coarse-grained molecular dynamics simulations of hybrid networks made of two types of strands. The model is built on the phantom network model of nonlinear springs which properties are derived from the force-deformation response of individual chains and are characterized by the Kuhn length, DP, and bond deformation potentials. The developed approach self-consistently accounts for entropic elasticity, bond deformation, and continuous redistribution of stress between different network strands as they undergo nonlinear deformations. The model predictions are tested by molecular dynamics simulations of hybrid network deformations. In particular, simulations confirm a breakdown of the simple mixture rule and the “weakest link” concept in the nonlinear deformation regime.