| Abstract: | The mean time spent by a macromolecule at a solid/liquid interface is analyzed in the region of adsorption saturation. The method consists of carrying out preliminary adsorption with radioactively labeled high-molecular-weight polyacrylamide and subsequently exposing the surface to a solution of unlabeled polyacrylamide. It was found that, apart from a small fraction of polymers “loosely” attached, the exchange between labeled and unlabeled polymers takes place at the interface at a very slow rate. Furthermore, desorption of surface molecules occurs only in the presence of a solution, and then the rate of desorption increases proportionally to the number of molecules in the solution. A mechanism based on a bimolecular chemical exchange process is proposed. |
