Ondes électromagnétiques de surface : application à l'étude de l'adsorption de polymères à l'interface solide-liquide

Electromagnetic surface waves : application to the study of the adsorption of polymers at the solid-liquid interface

• Auteur / Autrice : Yuying Longval-Zhang
• Direction : Yves Lévy
• Type : Thèse de doctorat
• Discipline(s) : Physique
• Date : Soutenance en 1988
• Etablissement(s) : Paris 11
• Partenaire(s) de recherche : Autre partenaire : Université de Paris-Sud. Faculté des sciences d'Orsay (Essonne)

Mots clés

Mots clés contrôlés

Polymères

Plasmons

Adsorption

Mots clés libres

Interface solide-liquide

Interface solide-gaz

Excitation optique

Résumé

Développement d'une méthode optique adaptée a l'étude des interfaces solide/liquide ou solide/gaz: réflexion totale atténuée en excitation optique du plasmon de surface. Application a l'étude de l'adsorption du polystyrène sur une paroi en bon solvant (toluène) et en solvant thêta (cyclohexane). La cinétique d'adsorption, l'isotherme d'adsorption, l'épaisseur et la concentration moyenne de la couche adsorbée sont comparables à ceux obtenus par ellipsométrie

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.