סמינר לפיזיקה של מערכות ביולוגיות וחומרים רכים: Theory and Simulations of Charge Regulation of Colloidal Particles in Electrolyte Solutions
Yan Levin, Institute of Physics, UFRGS
Prof Levin will discuss a theory that enables us to calculate the effective surface charge of colloidal particles and to efficiently obtain titration curves for different salt concentrations. The theory accounts for the shift of pH of solution due to the presence of 1:1 electrolyte. It also accounts self-consistently for the electrostatic potential produced by the deprotonated surface groups. To examine the accuracy of the theory, we have also developed a reactive grand canonical Monte Carlo simulations method to treat charge transfer at the colloidal surface. An excellent agreement is found between theory and simulations, without any adjustable parameters. He will also discuss the problems associated with the usual constant pH simulation methods often used in the literature.