2023 AIChE Annual Meeting
Characterization of Carbon Dioxide-Reacted Polypeptide Complex Coacervates
In this work, we examine the formation of complex coacervates using oppositely charged polyelectrolytes, poly(L-lysine) and poly(L-glutamic acid), and, subsequently, explore the ability of these complex coacervates for enhanced carbon dioxide sequestration. We create a âcore-and-shellâ coacervate droplet using a 2:1 ratio of poly(L-lysine) to poly(L-glutamic acid). We find that this ratio results in atypically small coacervates creating a higher surface area to volume ratio. This greater ratio allows for more possible reaction sites. The proposed mechanism is that the poly(l-lysine) on the surface of the complex coacervates will react with the soluble carbon dioxide to form carbamate. Samples were sparged with carbon dioxide for varying amounts of time, and the change in their size, charge, and chemistry was explored through Dynamic Light Scattering (DLS), Zeta potential, and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). DLS measurements for samples that were sparged for 1 hour show a slight increase in size, followed by a slight decrease in size. Zeta potential measurements show two significant charge peaks for samples that were sparged for 1 hour, suggesting the reaction resulted in a secondary charged species. ATR-FTIR is being explored to quantify the evolution of the carbamates in the complex coacervate droplets.