Directly Modifying the Nonbonded Potential Based on the Standard Iterative Boltzmann Inversion Method for Coarse-Grained Force Fields

Abstract

Effective potentials are of great importance for coarse-grained (CG) simulations, which can be obtained by the structure-based iterative Boltzmann inversion (IBI) method. However, the standard IBI method is incapable of maintaining the mechanical and thermodynamic properties of the CG model in agreement with those of the all-atom model. Unlike the existing techniques, such as introducing friction force as the dissipative force to reduce the superatom motion while keeping the conservative force arising from the CG potential intact, we directly modified the standard IBI nonbonded potential by adding an empirical function. According to an analysis of the dissipative particle dynamics, the additional function did compensate for the friction reduction of the standard IBI CG model. In this work, the thermal fluctuation information from the nonbonded radial distribution function was incorporated into the additional empirical function. As an illustration of the new CG force fields, we presented simulations of the stress-strain relation and thermodynamic properties in terms of cis-polyisoprene and compared the statistical structure information of the superatoms with those of the IBI CG model and the all-atom model. It should be emphasized that the additional empirical function contributed to compensating for the friction reduction, irrespective of the functional form it took. In this sense, the proposed method was easily operable.

A comparative study on the interfacial characteristics and tensile behaviors of natural rubber composites reinforced by carbon and boron nitride nanotubes

“…The Tersoff potential proposed by Kinaci et al [ 33 ] was used to describe the interactions between boron and nitrogen atoms in BNNTs. The CVFF, Airebo, and Tersoff potentials have been successfully and widely used for the evaluation of mechanical properties of NR polymer, [ 34 ] CNTs, [ 35 ] and BNNTs. [ 36 ] The non‐bonded interactions between CNT, BNNT and NR matrices were represented by Coulomb and vdW interactions, which were calculated, respectively, by using the Ewald method and 12‐6 Lennard‐Jones (LJ) potential with a cutoff distance of 1.25 nm.…”

Temperature Transferable and Thermodynamically Consistent Coarse-Grained Model for Binary Polymer Systems

“…However, the original IBI method does not guarantee the transferability of the developed CG potential at a specific state point over different temperatures and thermodynamic states. , To date, many efforts have been devoted to the development of CG models for single-component polymer systems. Encouragingly, good thermodynamic representability − and transferability ,− have been achieved by using necessary modifications or refinements.…”

Coarse‐grained molecular dynamics simulation of polymers: Structures and dynamics

“…However, this method sacrifices structural accuracy. Tan et al 133 introduced wave‐like functions into IBI potentials to mimic the fluctuations or roughness during collisions of CG particles. They added an auxiliary perturbation term to IBI iterations to simulate the long‐range fluctuations of the radial distribution function () in AA models.…”