Colloidal interactions

The present topical review describes the concept of effective interactions between spherical colloids in bulk solution. An introductive analysis based on the statistical mechanics of liquids and mixtures derives the main classes of colloidal forces observed at various solvent-solute compositions. A general survey of basic and advanced theories on ion-averaged interactions between charged colloids ends with a critical examination of recent statements on the existence of colloidal attraction and liquid-gas phase separation of pure electrostatic origin.