Transition from incomplete to complete wetting of solid surface in polymer-solvent system: 2. The regime of strong adsorption

The transition from incomplete to complete wetting of the solid surface by a semidilute polymer solution coexisting at equilibrium with the very-dilut e polymer solution was studied using the Canh-de Gennes theory under the co nditions corresponding to the tricritical state of semidilute solution and strong adsorption of the chain units on a substrate. It was established tha t the wetting transition can occur as the first- or second-order phase tran sition or as the transition of tricritical wetting depending on the repulsi on energy of segments that are on the substrate surface. Near the temperatu res of these transitions, the character of the variations in the difference s of surface concentrations that are established at the boundaries of the s ubstrate with semidilute and dilute polymer solutions, as well as in the di fferences of interfacial tensions and the cosine of contact angle were dete rmined. It was shown that the temperature of each of these phase transition s varies in proportion to the surface potential of the substrate and does n ot depend on the polymer molecular mass. The observed behavior differs esse ntially from that established near the critical point of a polymer-solvent system.