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 ϕ( 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 2 h . We find that irreversible adsorption might represent a more efficient way of protecting the particles against coalescence than grafting.