Nonlinear mechanics of triblock copolymer elastomers: from molecular simulations to network models

We introduce an entropic network model for copolymer elastomers based on the evolution of microscopic chain conformations during deformation. We show that the stress results from additive contributions due to chain stretch at the global as well as entanglement level. When these parameters are computed with molecular simulations, the theory quantitatively predicts the macroscopic stress response. The model requires only one elastic modulus to describe both physically crosslinked triblock networks and uncrosslinked homopolymers.