(255ba) Pore Size Tuning of Poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) Hypercrosslinked Polymers: Insights from Molecular Simulations

Hypercrosslinked polymers (HCPs) are highly porous materials that are attracting increasing interest due to their potential in energy applications. Furthermore, HCPs are considered low-cost and lightweight material with exceptionally high surface area, high thermal stability and relatively robust against chemical degradation. These attractive characteristics from HCPs make them an excellent candidate for important industrial applications such as gas capture, gas storage, catalyst applications, and separation processes.

In this study, the structure-property relationships of HCPs, poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene), were investigated using atomistic simulations. A virtual polymerization algorithm, Polymatic, was used to synthesize the HCPs in silico. To ensure the conformity of our simulated samples, the structures were validated with experimental data including BET surface area, micropore volume, and gas loading (H₂ and CO₂). Furthermore, the influence of the degree of cross-linking on polymer structures was analyzed, and it was observed that, as expected, both the surface area and micropore volume increase as a function of the degree of cross-linking. We also investigated if divinylbenzene molar content in HCPs can be varied to tune the porosity of the polymer structure in order to improve H₂/CO₂ gas separation performance. Specifically, we varied the divinylbenzene content from 0 to 50 mol% and evaluated how structural and gas separation performance changes. Our results demonstrated that divinylbenzene can be used as a porosity tuning agent and it significantly affected the structure and properties of the polymer. However, no significant improvement in H₂/CO₂ gas separation in pressure swing adsorption process with respect to varying divinylbenzene molar content was observed, in contrast with experimental forecast.