A theory of equilibrium adsorption in solution onto planar surfaces in the framework of the Arrhenius approach and the Lucassen-Reynders convection has been considered. The adsorption of water-soluble polymers on silicon wafers and polystyrene films under flow conditions was studied by ellipsometry. Equations were derived to calculate: (a) the thickness of the adsorbed layer, (b) the amount of polymer adsorbed, (c) the equilibrium constant of adsorption, and (d) the activation energy of adsorption. O 1998 Elsevier Science Ltd. All rights reserved.