Polymer Sorbent Design for the Direct Air Capture of CO₂

Anthropogenic activities have resulted in enormous increases in atmospheric CO₂ concentrations particularly since the onset of the Industrial Revolution, which have potential links with increased global temperatures, rising sea levels, increased prevalence, and severity of natural disasters, among other consequences. To enable a carbon-neutral and sustainable society, various technologies have been developed for CO₂ capture from industrial process streams as well as directly from air. Here, direct air capture (DAC) represents an essential need for reducing CO₂ concentration in the atmosphere to mitigate the negative consequences of greenhouse effects, involving systems that can reversibly adsorb and release CO₂, in which polymers have played an integral role. This work provides insights into the development of polymer sorbents for DAC of CO₂, specifically from the perspective of material design principles. We discuss how physical properties and chemical identities of amine-containing polymers can impact their ability to uptake CO₂, as well as be efficiently regenerated. Additionally, polymers which use ionic interactions to react with CO₂ molecules, such as poly(ionic liquids), are also common DAC sorbent materials. Finally, a perspective is provided on the future research and technology opportunities of developing polymer-derived sorbents for DAC.