Multicomponent adhesive hard sphere models and short-ranged attractive interactions in colloidal or micellar solutions

Domenico Gazzillo, Achille Giacometti, Riccardo Fantoni, Peter Sollich
2006 Physical Review E  
We investigate the dependence of the stickiness parameters t_ij=1/(12τ _ij) -- where the τ_ij are the conventional Baxter parameters -- on the solute diameters σ_i and σ_j in multicomponent sticky hard sphere (SHS) models for fluid mixtures of mesoscopic neutral particles. A variety of simple but realistic interaction potentials, utilized in the literature to model short-ranged attractions present in real solutions of colloids or reverse micelles, is reviewed. We consider: i) van der Waals
more » ... ctions, ii) hard-sphere-depletion forces, iii) polymer-coated colloids, iv) solvation effects (in particular hydrophobic bonding and attractions between reverse micelles of water-in-oil microemulsions). We map each of these potentials onto an equivalent SHS model, by requiring the equality of the second virial coefficients. The main finding is that, for most of the potentials considered, the size-dependence of t_ij(T,σ_i,σ _j) can be approximated by essentially the same expression, i.e. a simple polynomial in the variable σ_iσ_j/σ_ij^2, with coefficients depending on the temperature T, or -- for depletion interactions -- on the packing fraction η_0 of the depletant particles.
doi:10.1103/physreve.74.051407 pmid:17279909 fatcat:sq5kzzbl6vgwtiq3rsnenntvna