Planned Multilayer Assemblies by Adsorption

Adsorption at liquid solid interfaces is employed to construct organized multilayer structures on polar solid substrates. We have recently demonstrated that oriented compact monolayers of good quality can be obtained under suitable conditions either by physisorption or by chemisorption, using either pure compounds as adsorbates or mixtures of several components, and even using mixtures of both physisorbed and chemisorbed species.¹ Monolayer formation by adsorption offers certain important advantages as compared with the Lanmuir-Blodgett method; adsorption is a spontaneous process leading to thermodynamically equilibrated film structures, there is no mechanical manipulation of the films, water is not indispensable for monolayer formation, monolayer composition and structure are usually dependent on the chemical nature and microscopic organization of the solid surface, covalent binding to the substrate and intralayer polymerization may take place simultaneously with the monolayer formation process, there are no restrictions regarding the macroscopic shape and size of the substrate. However, the adsorption method has been so far shown to be suitable only for formation of single mono-layers,¹ which limited severely its usefulness in the construction of multilayer assemblies.