Molecular recognition under formation of amphiphilic amidinium carboxylates at the air-water interface

Amphiphilic "host-guest" assemblies are formed between a "host" monolayer and "guest" molecules dissolved in the acqueous subphase by acid base interactions. The specific features of the surface films of amphiphilic benzamidinium benzoate complexes are determined by surface pressure-area isotherms, Brewster-angle microscopy and atomic force microscopy studies. Molecular recognition of the dissolved component by the amphiphilic monolayer causes drastic changes in the properties of the surface film. Not only the area per molecule is considerably increased but also condensed-phase domains of special texture and topography can be formed. Details of a specific substructure reveal that a second layer grows over the primary structures at further compression.