Colloidal Dispersions in Polymer Melts

Whereas the effect of adding soluble polymers to colloidal dispersions has been studied widely, relatively little work has been published on dispersions in polymeric liquids containing little or no solvent. Two situations will be considered in this work, the first being that in which the particles are coated in a dense layer of short, oligomeric chains having a molecular weight several orders of magnitude lower than that of the continuous phase. In this case, a steric repulsion between the particles on the length scale of the interfacial layer is, arguably, inevitable. The second is the counter case in which the tethered chains are macromolecular and the coverage is low relatively. Calculations made using Scheutjens-Fleer self-consistent field theory are used to show that, although the screening is very profound, it does not necessarily render the long-range repulsion negligible relative to the van der Waals force.