Effect of Chain Polydispersity on the Elasticity of Disordered Polymer Networks
Valerio Sorichetti, Andrea Ninarello, José Ruiz‐Franco, Virginie Hugouvieux, Walter Kob, Emanuela Zaccarelli, Lorenzo Rovigatti
Abstract
. We rationalize this dependence by employing a generic stress-strain relation for polymer networks that does not rely on the specific form of the polymer end-to-end distance distribution. We find that the shear modulus of the networks is a nonmonotonic function of the density of elastically active strands, and that this behavior has a purely entropic origin. Our results show that if short chains are abundant, as it is always the case for randomly cross-linked polymer networks, the knowledge of the exact chain conformation distribution is essential for correctly predicting the elastic properties. Finally, we apply our theoretical approach to literature experimental data, qualitatively confirming our interpretations.