Pressure-induced coagulation of polystyrene latices

This paper describes the coagulation of surfactant-free homodisperse polystyrene latices of a wide range of surface charge by centrifugation. Electrostatically, the latices were characterized by their surface charge and electrokinetic potential. Experimental critical coagulation pressures at various concentrations of KCl have been compared with theoretical pressures, computed by a statistical thermodynamic method on the basis of a cell model, using DLVO pair potential energies. The agreement between theory and experiment is reasonable or good, except at very low electrolyte concentrations where the experimental results exceed the theoretical ones considerably. Two suggestions to explain this discrepancy are forwarded.