Electrochemical properties and stability of emulsifier-free polystyrene latexes in 1: 1 electrolyte solutions

The electrokinetic and adsorption characteristics of monodisperse emulsifier-free latexes of polystyrene (particle sizes of 0.25–0.40 μm) with surface carboxyl and sulfo groups are comprehensively studied depending on pH and the concentration of background NaCl solutions. The constants of surface carboxyl group dissociation and surface complexation, as well as the adsorption potentials of OH^? and Na⁺ ions, are calculated. The stability of latex suspensions is investigated and the coagulating concentrations of NaCl and HCl solutions are determined. An analysis of the curves plotted for the pair interaction between latex particles at different concentrations of NaCl solutions suggests that the system possesses an additional stability factor, which is probably associated with polymer chains that protrude over the particle surface into a solution.