Towards a complete configurational theory of non-equilibrium polymer adsorption

Abstract

A theory of non-equilibrium adsorption is presented in which a polymer profile is built up by the adsorption of incremental concentrations of polymer. Once each increment has been adsorbed, its surface concentration remains constant but the bulk profile can equilibrate, subject to this constraint, as more polymer is adsorbed. This is a more realistic theory of non-equilibrium adsorption than the theory presented by Barford et al. in J. Chem. Soc., Faraday Trans. 1, 1986, 82, 3233, as in that theory no equilibration of the adsorbate was allowed as more polymer was adsorbed. In this paper the free energy of the adsorbate as a function of adsorbate concentration, and hence the saturation concentration, and the polymer profiles at saturation are calculated as a function of a surface interaction term. It is shown that the results are essentially identical to those of Barford et al., leading to the conclusion that the simpler assumptions of Barford et al. were justified.