Leveraging dynamic bonds to probe equilibrium topology in polymer networks

Formation of chemically crosslinked polymer networks is a kinetically-driven process leading to local topological defects such as primary loops which decrease the elastic effectiveness of the network. Dynamic bonds in a network create possibilities for bond exchanges and network rearrangement, potentially altering topology. This work investigates how network topology changes as a result of incorporating dynamic bond rearrangements into an irreversibly-crosslinked network. Kinetic Monte Carlo simulations and experimental validation reveal that incorporating dynamic bond rearrangements leads to lower primary loop fraction and higher modulus. Such rearrangements lead to formation of a more strongly percolated structure and a greater number of higher-ordered cyclic structures in comparison to kinetically crosslinked networks. The quantitative change in the topology is dependent on the concentration and equilibrium constant, demonstrating that irreversible crosslinking occurs by an out-of-equilibrium process and that dynamic bonding can tune network topology.