Effect of Topological Defects on the Elasticity of Near-Ideal Polymer Networks

In recent years, new types of polymer gels have emerged, which have a well-controlled network structure and few topological defects. These so-called near-ideal polymer networks constitute a good model system to revisit the long-standing problem of structure–property relationships in polymer networks, as well as a promising platform for the development of polymer gels with outstanding mechanical properties. In this study, we investigate the relative contributions of network defects (dangling chains and second-order loops) on the stress–stretch response of near-ideal polymer networks using a computational discrete network model. We identify the average chain prestretch as a key parameter to capture the effect of network topology on the elastic modulus and maximum extensibility. Proper account of the chain prestretch further leads to scaling relations for the elastic properties in terms of topology parameters that differ from classical estimates of rubber elasticity theory. Stress–stretch curves calculated using the discrete network model are also compared to semi-analytical estimates.