Gel transitions in colloidal suspensions

The idealized mode-coupling theory (MCT) is applied to colloidal systems in teracting via short-range attractive interactions of Yukawa form. At low te mperatures, MCT predicts a slowing down of the local dynamics and ergodicit y-breaking transitions. The non-ergodicity transitions share many features with the colloidal gel transition, and are proposed to be the source of gel ation in colloidal systems. Previous calculations of the phase diagram are complemented with additional data for shorter ranges of the attractive inte raction, showing that the path of the nonergodicity transition line is then unimpeded by the gas-liquid critical curve at low temperatures. Particular attention is given to the critical non-ergodicity parameters; this is moti vated by recent experimental measurements. An asymptotic model is developed , valid for dilute systems of spheres interacting via strong short-range at tractions; and is shown to capture all aspects of the low-temperature MCT n on-ergodicity transitions.