(364c) Explore the Mechanism of Polyelectrolytes Mediated Colloidal Stability

Polyelectrolytes are commonly used to regulate the stability of colloidal solutions, e.g., printing ink and oil. Despite the broad industrial applications of polyelectrolytes, the fundamental mechanism that accounts for distinctive behaviors of colloidal solutions in presence of various types of polyelectrolytes remains elusive. In this study, we explore the effect of a polyelectrolyte on the stability of the oppositely charged colloidal suspension. Using model polyelectrolyte, e.g., dsDNA, ssDNA, and model colloids, e.g., gold, silica and protein particles, we characterize the micro-structure, i.e., polymer adsorption pattern, polymer conformation and colloidal distribution, of the mixture system by various spectroscopy tools. Small variations of colloidal surface charges can lead to distinctive transitions in the conformation and adsorption pattern of the model polyelectrolyte. The observed phenomena are modeled to reveal the dominant interactions that accounts for the stability of the colloidal solution.  The revealed microscopic details of the system help us to elucidate the roles of a polyelectrolyte in mediating the critical interactions that lead to the formation and the maintenance of a colloid suspension.