PAIR POTENTIALS BETWEEN POLYMER-COATED MESOSCOPIC PARTICLES

A self-consistent-held model is developed which enables the calculatio n of the interaction potential between two polymer-coated mesoscopic p articles. We use a cylindrical coordinate system, in which the polymer density profile can vary in both the radial and axial direction. Data are presented for the free energy of interaction for two particles wi th end-attached polymer chains in a good (athermal) solvent. The repul sion is considerably weaker than predicted by converting the pair pote ntial between flat plates to that between spheres, using Derjaguin's a pproximation. This is explained by the greater freedom of the polymer chains to move laterally out of the widening gap between the particles as compared to polymer chains between flat surfaces.