Nonlinear Network Deformation and Loop Effect

The characterization of network structure remains one of the unresolved problems of polymer science. To investigate the effect of the network topology and establish contributions from different network structural elements, we developed a forensic-like framework utilizing network response to nonlinear deformations. By applying this approach to coarse-grained networks of phantom strands studied by molecular dynamics simulations, we obtained the degree of polymerization of network strands between crosslinks, quantified the contributions of loops and dangling ends, and established the actual network functionality. In particular, we determined the loop coefficient for phantom networks C_loop = 0.87±0.04, which describes the reduction of the network structural modulus by contributions from different types of loops. Furthermore, our analysis showed that the dangling ends not only influence the density of the stress-supporting strands but also decrease the effective crosslink functionality.