Influence of gas sorption on dynamics of supported thin polyamine films

Supported thin polyamine films have been identified as one of the most promising geometries for carbon dioxide capture, especially from dilute sources. Despite the extensive characterization of the chemical reactions between carbon dioxide and the amine groups, their influence on the dynamics of thin polyamine films remains largely unexplored. In this work,[1] we compare the dynamics of supported thin polyethylenimine (PEI) films before and after carbon dioxide absorption through broadband dielectric spectroscopy (BDS). Detailed analyses show carbon dioxide absorption slows down the PEI dynamics. Further in-situ kinetic measurements demonstrate non-monotonic changes in relaxation times or dielectric amplitudes of some processes during carbon dioxide sorption or desorption, suggesting an intriguing interplay between carbon dioxide chemisorption and the dynamics of supported thin PEI films. These results demonstrate that BDS is a powerful platform for resolving the carbon dioxide sorption-induced dynamics changes of thin polyamine films.

[1] M. Tress, S. Ahmadi, and S. Cheng, In situ monitoring of CO2 sorption on polyethylenimine dynamics through broadband dielectric spectroscopy AlChE J., DOI: 10.1002/aic.18627 2024.