ELLIPSOMETRY, BREWSTER-ANGLE MICROSCOPY, AND THERMODYNAMIC STUDIES OFMONOMOLECULAR FILMS OF CRYPTOPHANES AT THE AIR-WATER-INTERFACE

The cryptophanes are spherical or ovoid-shaped hollow molecules of nan ometric scale capable of forming inclusion complexes with neutral or c harged organic species. Certain cryptophanes such as 1-4 form thin fil ms when they are compressed at the air-water interface. These films ha ve been studied by surface pressure measurements, ellipsometry and Bre wster angle microscopy. The medium-sized cryptophane 2 and the large c ryptophanes 3 and 4 exhibit a reversible monomolecular layer domain li mited to a surface pressure of 8-10 mN m(-1) and generated after a pla teau corresponding to a gas-liquid transition. In contrast, molecular films of the small cryptophane 1 are not stable and irreversibly colla pse to 3D-aggregates when they are compressed.