Study of the effect of pH and ionic strength on complex coacervates

Abstract

Associative complex coacervates formed by the spontaneous assembly of oppositely charged polyelectrolytes offers a variety of applications in the fields like system chemistry, bottom-up synthetic biology, etc. This project aims to understand the effect of pH, ionic strength, and polyelectrolyte concentration on associative phase separation and examine their sequestration behavior using dye as a guest for coacervate. We have employed two sets of oppositely charged polyelectrolytes/electrolytes for coacervate formation. The positively charged polyelectrolytes are poly (diallyldimethylammonium chloride) (PDDA) and diethylaminoethyl-dextran (DEAE) while the negatively charged polyelectrolyte is polyacrylic acid (PAA) and electrolyte adenosine triphosphate (ATP). The phase separation and formation of complex coacervates depend on the factors like polyelectrolyte length, charge density, pH, ionic strength. We were trying to understand how these factors affect coacervation. Also, the surface charge on the formed coacervates were probed via zeta potential studies and the nature of coacervates were investigated via sequestration studies using dyes.