POLYMER ADSORPTION - THE EFFECT OF THE RELATIVE SIZES OF POLYMER AND PARTICLE

The adsorption of relatively large polymers onto the surfaces of small particles is, potentially, fundamentally different from the ''normal'' ease where the substrate is assumed to be locally flat. In a concentrated dispersion of small particles, the separation of the particles is such that a large polymer may bridge the gap between two adjacent surfaces dependent on the surface coverage and the manner in which the adsorption sample is prepared. In this paper, we present data from small-angle neutron scattering (SANS) of high molecular weight poly(ethylene oxide) (PEG) adsorbed onto colloidal silica and solvent relaxation studies of a smaller PEO sample adsorbed onto a range of different sized silica particles. The effects of particle size and concentration and polymer molecular weight and concentration have been studied. Molecular dynamics (MD) simulations illustrate the importance of the-relative sizes of the adsorbent and adsorbate.