Multiscale Analysis of Amine‐Containing CO 2 Capture Membrane via Dissipative Particle Dynamics Simulations Using Ab Initio Elongation Method‐Based Parameters

ABSTRACT Our developed elongation (ELG) method, an ab initio linear‐scaling method for calculating the electronic structures of aperiodic polymers, was combined with dissipative particle dynamics (DPD) simulation to perform more reliable simulations using quantum chemistry (QC)‐based parameters. This was achieved by using the Valdivia–Jaime equations [Valdivia et al ., Soft Matter 17, no. 4 (2021): 1028–1036], connecting QC‐based hydration energy to the DPD repulsive parameter. The ELG‐DPD model was employed to analyze phase separation in an amine‐containing CO 2 capture membrane reported in Taniguchi's experiment [Taniguchi et al ., Science and Technology of Advanced Materials 18, no. 1 (2017): 950–958]. The ELG‐DPD results showed that poly(vinyl alcohol) hydrogel has higher performance on phase separation compared with poly(ethylene glycol), well reproducing the reported experiment. In contrast, simulations using the group contribution method, widely used for DPD parameters, showed the opposite trend from the experiment. The ELG‐DPD model was also applied to examine the effects of multi‐amine sites and hydroxyl (–OH) group in alkanoldiamine on the phase separation in the CO 2 capture membrane. The simulations showed that the phase separation is suppressed by including a secondary amine site, while it can be accelerated by the –OH group. Our previous QC reaction analysis [ Chemical Physics Letters 783 (2021): 139070; Physical Chemistry Chemical Physics 24, no. 23 (2022): 14172–14176] revealed that both the multi‐amine and –OH activate the CO 2 capture reaction. Comprehensively, multi‐amine has an advantage on both the mesoscopic phase separation and microscopic CO 2 capture reaction, while –OH group can cause a trade‐off between its mesoscopic disadvantage and microscopic advantage.