Validity of the hard-sphere mixture model for sterically stabilised colloids: a critical viewpoint

摘要

The validity of the hard-sphere mixture model for sterically stabilised colloids is discussed. The inadequacy of the hard-sphere mixture model in the context of pure colloid–solvent systems is analysed both at the experimental and at the theoretical level. A simple model is presented to discuss the respective weights of the direct solute–solute interaction and the indirect ones mediated by the solvent. The range of the size ratio in which the indirect one is relevant is examined. In this regime, the adequacy of the hard-sphere mixture as a reference system for perturbation treatments is investigated.