Application of the adhesive sphere model to the structure of colloidal suspensions

Abstract

The fluid of adhesive sphere (AS) is considered a tool for the investigation of the structure and thermodynamics of dispersed colloidal systems. We compare this model to a more realistic fluid such as the ‘‘square well fluid’’ where the interactions are of finite range and strength. Considering the Percus Yevick (PY) approximation, we show that the analytical solution of the structure factor of the AS fluid and the numerical solution for the square well fluid agree fairly well at all volume concentrations if the range of the square well does not exceed 10% of the particles diameter. By comparison to the modified hypernetted chain approximation (MHNC) and simulation data we show that the PY approximation is convenient for hard core potentials with a short range tail. Selected examples of application of the AS model as a reference system are given either for the inverse micelles with short range interactions or for nonionic systems invoking the external structurated water shell contribution as a repulsive barrier which is state dependent.