Abstract EN:

We have developped an optical method to study the inter­ faces of the solid/liquid or solid/gaz type: attenuated total reflexion in surface plasmon oscillations. We present the theoretical principle of themethod, its experimental systems, and its application to the study of polymer adsorption at a solide/liquid interface. We have realized a general computer programme to analyze the experimental data and adjust the values of the thickness and refractive index of the adsorbed film. We demonstrated that to a first approximation, the variation of the reflectivity at a given incident angle, is proportionnal to the adsorbance. We realized two different experimental systems, one using a mechanical scan of the incident angle, and the other performing angular measurements with an array of photodiodes. To demonstrate experimentally the ability of the system, we chose to investigate the adsorption of polystyrene on silver surface, from solution in a good solvant (toluene), and in a solvant theta (cyclohexane). The results obtained kinetics of adsorption, the adsorption isotherm, the average thickness and concentration of the film, are corn- pared to those observed in ellipsometry and other techniques. The conclusion proposes the perspectives for the development of this powerful technique and its application to various systems.