(382e) Parameterization of Dynamically Consistent Coarse-Grained Models of Chemically Specific Polymer Melts
AIChE Annual Meeting
Wednesday, November 18, 2020 - 9:00am to 9:15am
All-atom (AA) molecular dynamics models of polymeric materials are the most accurate methods for calculating structural and dynamical properties that are comparable to experimental measurements but are computationally expensive and limited in both the length and time scales that can be achieved. Coarse-grained (CG) models, in which many atoms are lumped into fewer CG sites, enable faster, cheaper simulations, however the simplification required creates challenges in agreement with the original AA system. âBottom-upâ CG methods capture chemically-specific details â an example is iterative Boltzmann inversion (IBI) which captures structural properties from short reference atomistic simulations. A significant problem in this area is that such bottom-up methods suffer from unphysically fast dynamics due to the smoother potential energy landscape. One means to address the problem of accelerated dynamics is by incorporating nonconservative forces into the CG potential which have been introduced to great effect in CG models which address universal aspects of polymer dynamics. Here, we study the development a chemically specific, thermodynamically consistent, and dynamically correct model by augmenting the bottom-up coarse-grained model with a dissipative potential. First, we utilize custom code for IBI to parameterize the conservative potential for model melt-state oligomer systems. Then, we study several approaches for parametrizing the dissipative potential and examine the degree of self-consistency. We discuss the practical implications of a proxy for tuning monomeric friction and further considerations for the optimization of conservative and dissipative potentials.