Comprehensive Structural Characterization of Charged Polymers Involved in Moisture-Driven Direct Air Capture

Gayathri Yogaganeshan; Rui Zhang; Raimund Fromme; Sharang Sharang; Jamie Ford; Douglas M Yates; Marlene Velazco Medel; Martin Uher; Justin Flory; Jennifer Wade; Petra Fromme

arXiv · 2508.11809

Comprehensive Structural Characterization of Charged Polymers Involved in Moisture-Driven Direct Air Capture

Gayathri Yogaganeshan·Rui Zhang·Raimund Fromme·Sharang Sharang·Jamie Ford·Douglas M Yates·Marlene Velazco Medel·Martin Uher·Justin Flory·Jennifer Wade·Petra Fromme

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Abstract

The rise in atmospheric carbon dioxide (CO2) levels has led to urgent calls for effective carbon capture methods, with direct air capture (DAC) emerging as a promising solution. This study focuses on the structural characterization of commercially available alkaline anion-exchange membrane (AEM) polymers, Fumasep FAA-3 and IRA 900, for use in low-energy, moisture-driven DAC applications. A combination of X-ray diffraction, small and wide-angle X-ray scattering (SAXS/WAXS), atomic force microscopy (AFM), focused ion beam-scanning electron microscopy (FIB-SEM), and transmission electron microscopy (TEM) were employed to explore the structural features of these materials. X-ray scattering analysis revealed molecular ordering and large-scale structural organization in both materials, while humidity-induced changes highlighted the impact of moisture on structural properties. AFM surface analysis further indicated the presence of clustering, porosity, and swelling, which were corroborated by FIB-SEM and TEM imaging. These structural insights offer a deeper understanding of the behavior of AEM-DAC materials during CO2 capture and release, emphasizing the role of moisture in these processes. This work lays the foundation for the development of more energy-efficient DAC polymers, paving the way for improved CO2 capture technologies.

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Gayathri Yogaganeshan, Rui Zhang, Raimund Fromme, Sharang Sharang, Jamie Ford, Douglas M Yates, Marlene Velazco Medel, Martin Uher, Justin Flory, Jennifer Wade, Petra Fromme. 2025-08-15. Comprehensive Structural Characterization of Charged Polymers Involved in Moisture-Driven Direct Air Capture. https://arxiv.org/abs/2508.11809

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