Oral: Low-Temperature Phase Diagram of Polyelectrolyte-Water Systems

Polyelectrolyte polymers have many different applications, ranging from medical devices, anti-fouling surfaces, low friction surfaces, anti-ice coatings, and cryopreservation. While these polyelectrolyte polymers are extensively studied in solution with water, there is a large gap in understanding how these interactions change at temperatures below the melting point of water. We have measured the phase diagram of positively (poly[2-methacrylolyloxyethyltrimethylammonium chloride]) and negatively (poly[3-sulfopropyl methacrylate potassium]) charged polyelectrolytes using infrared spectroscopy and thermal measurements using a differential scanning calorimeter. Using these methods, we can identify the amount of trapped unfrozen water in these systems at low temperatures and how the concentration of the two-phase system changes with temperature. This work can be used to understand the consequences of using these systems for controlling ice adhesion and friction.