Volume-term theories of phase separation in colloidal systems and long-range attractive tail in the pair potential between colloidal particles - art.no. 011503

To explain the experimental observation that colloidal dispersion exhibits a "two-state" structure under certain conditions, Sogami and Ise (SI) propo sed a model for an "effective" pair potential between colloidal particles w hich had an "attractive tail" more than a decade ago. The SI paper spawned several papers that dwelled on the shortcoming of the SI paper or strived t o provide other explanations for the observed inhomogeneity of the suspensi on. We show herein that a long range attraction in the pair potential betwe en colloidal particles is also obtained in "volume-term" theories in which the repulsive DLVO potential is retained.