Interaction between colloids in network forming solution

The effective interaction between colloids in a solvent of hard spheres, wh ich can polymerize with the formation of cross-like molecular clusters, is studied on the basis of the solution of the associative Percus-Yevick/Ornst ein-Zernike equation for spatial correlations in an infinitely dilute solut ion. It is found that at low solvent density and low temperature, the effec tive intermolecular potential between the colloidal particles is attractive , thus facilitating a phase separation or precipitation of the colloids. A depletion of the local solvent density around the colloidal particle is obs erved. If the solvent consists of extended associative complexes, compared with hard spheres, the correlation between the colloid particles are of lon ger range and barrier for flocculation shifts to the larger separations. Th e effect of size ratio of the colloid spheres and of solvent on the potenti al of mean force is also discussed. (C) 1998 Academic Press.