Accelerated ReaxFF Simulations of Vitrimers with Dynamic Covalent Adaptive Networks

In a recent publication, the authors employed the ReaxFF reactive force field along with the bond boost implementation available in AMS2024 to investigate the viscoelastic behavior of vitrimers.

Vitrimers, a promising class of sustainable polymers, consist of dynamic covalent networks that allow for reprocessability and recyclability through bond-exchange reactions. However, existing modeling approaches often fail to fully capture the underlying reaction pathways, limiting the molecular-level understanding of their viscoelastic properties. To address this limitation, the authors extended and applied the Accelerated ReaxFF technique—also known as the bond boost method—within the AMS2024 framework.

Bayesian optimization was used for force field parameter selection, and an empirical function was introduced to model the temperature dependence of reaction probabilities. This enhanced framework was applied to simulate the nonisothermal creep behavior of vitrimers under various stress levels, heating rates, and numbers of reactions. The simulation results show good agreement with experimental data reported in the literature, supporting the validity of the approach and offering molecular insight into vitrimer viscoelasticity.