Developing a Transferable Coarse-Grained Model for the Prediction of Thermodynamic, Structural, and Mechanical Properties of Polyimides at Different Thermodynamic State Points

Abstract

In the present work, we develop a coarse-grained (CG) model for polyimide (PI) at 800 K and 1 atm by applying iterative Boltzmann inversion (IBI) and the density correction method to derive the bonded and nonbonded interaction potentials. Although the CG force field is built at a single thermodynamic state point without any temperature correction, the CG model possesses a rather favorable temperature transferability in a wide temperature range of 300–800 K at P = 1 atm and a good pressure transferability to some extent in a certain pressure range from 0.1 to 30 MPa. In addition to the local conformation and local packing distribution functions, the thermodynamic properties such as the glass transition temperature and the coefficient of linear thermal expansion are predicted correctly by the CG model, and the isothermal compressibility coefficients calculated from both atomic and CG models are on the same order of magnitude. Additionally, the stress–strain behavior under compression or tension of the CG model shows a qualitative agreement with the atomistic results, and the corresponding values of the elastic modulus of the CG model at different temperatures roughly match with those of the atomistic model.

Coarse-Grained Molecular Dynamics Modeling of a Branched Polyetherimide

“…[50,51] Several methods of deriving coarse-grained potentials, including bottom-up approaches such as iterative Boltz-mann inversion (IBI), [52][53][54] inverse Monte Carlo, [55,56] force matching, [57][58][59], the relative entropy, [60,61] and the reversible work, [62] and various top-down or mixed approaches, [63][64][65][66] have been developed. Several groups have applied these methods to construct coarse-grained MD models of polyimides [67][68][69][70][71][72][73] and polyetherimides. [74][75][76] Clancy et al coarse-grained polyimides based on the BPDA dianhydride and three different APB diamine isomers into chains of linked vectors and used such linked-vector chains to quickly obtain relaxed configurations of the polymers that can be reverse-mapped to atomistic systems.…”

“…[50] Recently, Hu et al constructed a transferable coarse-grained MD model based on the IBI approach combined with the density correction method to predict the thermodynamic, structural, and mechanical properties of Kapton. [73] Clearly, more efforts are needed along this direction for polyimide and polyetherimide polymers. In this paper, we aim to develop a coarsegrained model for a branched polyetherimide that is not only transferable but also expandable.…”

Inverse Boltzmann Iterative Multi-Scale Molecular Dynamics Study between Carbon Nanotubes and Amino Acids

“…IBI is a multi-scale simulation method that has attracted the attention of many researchers in recent years [14][15][16][17][18] . It can effectively modify the coarse-grained model derived from the mean-field.…”

tSPICA: Temperature- and Pressure-Dependent Coarse-Grained Force Field for Organic Molecules

“…Hu et al published a model that aimed at the transferability of both T and P up to 800 K and 30 MPa. 32 Recently, Cao and Sun created a temperature-dependent model for alkane chains based on the Shinoda−DeVane−Klein (SDK) FF, 33 which was later expanded to polyethers. 34 Cao divided the Lennard−Jones (LJ) parameters into separate components and the so-called entropic components were linearly scaled for alkane chain beads.…”

“…The majority of models focus only on T dependence. Hu et al published a model that aimed at the transferability of both T and P up to 800 K and 30 MPa . Recently, Cao and Sun created a temperature-dependent model for alkane chains based on the Shinoda–DeVane–Klein (SDK) FF, which was later expanded to polyethers .…”