A Chemical Engineering (ChE) undergraduate student, Cameron Johnston, who works under the supervision of ChE Professor Sarah Perry, won a best poster award at the 2015 American Chemical Society Connecticut Valley Section Undergraduate Research Symposium. The title of the winning poster was “Effect of polymer architecture and zwitterionic moieties on complex coacervation.” Johnston’s research is a collaborative effort between Dr. Perry's lab and Todd Emrick’s lab, with one of his graduate students, Rachel Letteri.
As the poster abstract stated, “Complex coacervation is an associative liquid-liquid phase separation driven by electrostatics and is used in a variety of industries including cosmetics, food, and medicine. This phenomenon has been demonstrated in aqueous solutions of oppositely-charged polypeptides and other polyelectrolytes. Factors that affect complex coacervation include the polycation to polyanion ratio, temperature, pH, and polymer concentration. However, little work has been done to examine the effect of polymer architecture on complex coacervation. Here, we investigate the coacervation of cationic comb polymers with pentalysine groups pendant to a flexible polymer backbone with polyglutamic acid, an anionic polypeptide. Additionally, the effect of zwitterions, functional groups composed of positive and negative charges, on the coacervation of these comb polymers is studied by complexing pentalysine comb polymers having various amounts of zwitterionic pendant groups with polyglutamic acid. This study sheds light on complex coacervation, specifically on methods to tailor coacervate properties using macromolecular design features." (May 2015)