Abstract
The kinetic/adsorption properties of polyethylene glycol (PEG) on an alumina surface were examined. The influence of the molecular weight of PEG and of changes in the pH of the solution on the electrical properties at the solid/polymer solution interface were considered. The data obtained allowed the main factors responsible for the observed zeta potential and the surface charge changes on the A12O3 surface to be determined. The calculated differences in the values of the surface charge (Δσd) and in the charge on the diffuse layer (Δσd) for the A12O3/NaCl and A12O3/PEG-NaCl systems enabled a mechanism to be proposed for the zeta potential changes. It was confirmed that the molecular weight of the polymer has an influence on the calculated thickness of the PEG adsorption layer on the alumina surface and thus on the conformation of the polymer chain in the near-surface region. The pH of the solution also affects the thickness of the adsorbed layers on the A12O3 surface by influencing the interaction between the surface groups of the oxide and the conformational structures of the adsorbed macromolecule at the alumina/polymer solution interface.