Diffusiophoresis in a near-critical binary fluid mixture

We consider placing a rigid spherical particle into binary fluid mixture in the homogeneous phase near demixing critical point. The surface is assumed to have short-range interaction with each component and attract one more than other. Owing large osmotic susceptibility, adsorption layer, where preferred concentrated, can be of significant thickness. This causes motion under an imposed composition gradient. Thus, diffusiophoresis emerges from mechanism which has not been considered so far. calculate how mobility depends on temperature size.