IRREVERSIBLE ADSORPTION OF A POLYMER MELT ON A COLLOIDAL PARTICLE

We study the irreversible adsorption of linear polymer chains from a melt onto a spherical particle of radius R. This study generalizes the recent model of Guiselin for the irreversible adsorption of linear chains onto a planar surface. Our main motivation is the major role played by adsorbed polymer layers in the stabilization of colloidal particles. We consider the following sequence of events: a) the particle is put in contact with the polymer melt, all the monomers touching the surface adsorbing instantaneously and irreversibly, b) the particle is then washed out with pure solvent. Using scaling argument, we derive the volume fraction profile phi(r) (where r is the distance from the centre), the external radius R(c) and the free energy F of the adsorbed layer. We then estimate the force F(h) between two particles separated by a distance 2h. We find that irreversible adsorption might represent a more efficient way of protecting the particles against coalescence than grafting.