LANGMUIR-SCHAEFER FILMS - HEAD GROUP INFLUENCE ON ORIENTATION OF SUBSTITUTED STYRYL BIPYRIDINES

Nine new 4,4'-bis(4-substituted-styryl)-2,2'-bipyridines were synthesized and characterized. These new materials and 4,4'-bis(4-methylstyryl)-2,2'-bipyridine were applied to the subphase of a Langmuir trough. Eight of the ten compounds (R = CN, COOCH3, N(CH3)(2), COOH, OCOCH3, NO2, OCH3, CH3) made stable Langmuir films. These films were transferred by horizontal lifting to a variety of solid surfaces with transfer ratios close to unity. The transferred films were analyzed by transmission UV-vis, transmission IR, grazing angle reflectance IR, and polarized attenuated total reflectance IR spectroscopies. Of the eight materials, two, 4,4'-bis(4-acetylstyryl)-2,2'-bipyridine and 4,4'-bis(4-methylstyryl)-2,2'-bipyridine produce stable, highly anisotropic films. The other compounds form films with varying anisotropy from moderately anisotropic to totally isotropic. Thus, functional groups can have a profound influence on the ability of these materials to form stable LS films and direct the net material orientation within the films.