Energy renormalization for coarse-graining of thermomechanical behaviors of conjugated polymer

Y Wang and ZF Li and KM Niu and WJ Xia, POLYMER, 256, 125159 (2022).

DOI: 10.1016/j.polymer.2022.125159

Conjugated polymers (CPs) with the characteristics of relatively rigid conjugation backbone and peripheral flexible side-chain have drawn considerable attention in applications of organic optoelectronic devices. However, the "bottom-up" prediction of the thermomechanical behavior of CPs to serve the needs of devices design and prediction of their performance is challenging due to the prohibitive computational times of all-atomistic (AA) simulations. Coarse-grained (CG) modeling is an essential strategy for making progress on this problem. In this study, taking the amorphous poly(3-hexylthiophene) (P3HT) as a representative CP model system, we develop a temperature transferable CG model based upon the recently proposed "energy-renormalization" (ER) approach, allowing for preserving their glass-forming dynamics over a wide temperature range under coarse-graining. Specifically, our results show that the developed CG model faithfully captures the relaxation dynamics of its atomistic counterpart to a good approximation. Systematic evaluation of tensile and shear response reveals that the cohesive interaction exhibits a great impact on the mechanical behaviors of amorphous bulk polymer. Our work demonstrates the efficiency of ER strategy towards coarse-graining of CPs for their thermomechanical behaviors, and sheds new light on the design of other relevant polymers with heterogeneous chain architectures via bottom-up prediction.

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