The Goldilocks Principle and Carbon Capture
Burning coal, oil, and other fuels releases pollutants, including carbon dioxide. Materials are needed to extract the carbon dioxide quickly and efficiently, and release it on command. A promising material is poly(ethylenimine), or PEI, coated onto the inside of miniscule silica tubes, bonded together in a honeycomb structure. Investigation of how these materials form helped scientists discover something interesting. Adding a little PEI to the tubes created a thin layer of PEI inside the tubes, allowing the carbon dioxide to pass through--forming a coating that bound to the tubes, not the carbon dioxide. Adding more PEI created islands of material that could catch carbon dioxide more effectively, but adding too much caused plugs to form, blocking air flow. This understanding of how PEI fills the silica tubes is helping the team optimize current materials and design new materials for carbon capture. The team did this work at Center for Understanding and Control of Acid Gas-Induced Evolution of Materials for Energy (UNCAGE-ME) led by the Georgia Institute of Technology.
Holewinski A, MA Sakwa-Novak, and CW Jones. 2015. "Linking CO2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering." Journal of the American Chemical Society 137:11749-11759. DOI: 10.1021/jacs.5b06823