Enthalpy-driven adsorption of chain molecules onto chemically heterogeneous surfaces

Statistical analyses have been employed to develop analytical expressions f or the surface coverage of chemically heterogeneous molecules adsorbed with extended-chain conformations onto chemically heterogeneous surfaces such t hat the single-chain adsorption enthalpy is minimized. Lateral interactions are neglected and a sufficient number of randomly distributed adsorption s ites are included on both substrate and adsorbate such that site interactio ns are assumed to be nonoverlapping but otherwise independent. Good agreeme nt is observed between the theoretical and experimentally determined surfac e fraction of a cationic polyacrylamide adsorbed from aqueous solution onto both a Nafion(R) ionomer membrane and numerous nonionic polymeric substrat es. The more unique theoretical predictions for such enthalpy-driven adsorp tion processes are discussed. (C) 2001 Academic Press.