Organic polymers and CO2 capture. The role of polyethylenimine: 

In this study, the focus was on the use of polyethylenimine (PEI) as a method for capturing CO2 molecules directly from ambient air.1 The process involves depositing a PEI layer onto a microporous solid support, and the CO2 adsorption is achieved through a chemisorption process where the CO2 molecules react with the amine groups of the polymer. Although this process has been widely investigated experimentally, the further diffusion of CO2 molecules within this layer is heavily hindered, and the aim of this study was to elucidate this phenomenon from a nanoscale perspective using molecular dynamics simulations. 

To achieve this, the study started with a branched unreacted PEI chain and a branched reacted PEI chain, and three different systems were generated by arranging these two compounds in different configurations. The simulation results showed that CO2 molecules were more likely to interact with the branched reacted PEI chains due to their higher electrostatic attraction. As a result, their further diffusion towards the unreacted region, where Coulombic interactions are weaker, was strongly hindered and remained unexploited. 

Molecular dynamics simulations provide insight into the fundamental processes at the nanoscale that govern the behavior of molecules in a system. In this study, the simulations shed light on the molecular interactions between PEI and CO2 molecules, providing a deeper understanding of the CO2 capture process using PEI as a potential solution for reducing greenhouse gas emissions. 

The results of this study could have important implications for the development of new and more efficient methods for capturing CO2 from the atmosphere. By understanding the fundamental processes that govern the behavior of molecules at the nanoscale, researchers can design more effective materials and optimize existing systems to achieve better CO2 capture efficiency. This could be crucial in the development of more sustainable and environmentally friendly technologies to combat the growing threat of climate change. 

Overall, this study demonstrated the potential of molecular dynamics simulations as a powerful tool for investigating complex systems and providing insights into fundamental processes at the nanoscale. The findings could have significant implications for the development of new materials and technologies for reducing greenhouse gas emissions and mitigating the impacts of climate change. 


[1] Vanini, M., Khodayari, A., Eyck, D. Van, & Seveno, D. (2023). Molecular dynamics simulations of the interactions between CO2 and branched unreacted and reacted polyethylenimine films. Gas Science and Engineering, 111(March 2023), 204928.