EFFECT OF COMPLEMENTARY HYDROGEN-BONDING ADDITIVES IN SUBPHASE ON THESTRUCTURE AND PROPERTIES OF THE 2-AMINO-4,6-DIOCTADECYLAMINO-1,3,5-TRIAZINE AMPHIPHILE AT THE AIR-WATER-INTERFACE - STUDIES BY ULTRAVIOLET-VISIBLE ABSORPTION-SPECTROSCOPY AND BREWSTER-ANGLE MICROSCOPY

The present work is focused on the effects of hydrogen bonding on the 2-D properties of aminotriazine amphiphile 1 (2C(18)TAZ) by incorporat ing different complementary hydrogen bonding components in the subphas e. The structural organization of 1 at the air-water interface in the presence of barbituric acid (BA), barbital (BT), and cyanuric acid (CA ) was examined by surface pressure-area isotherm measurements, Ultravi olet-visible (UV-vis) absorption spectroscopy, and Brewster angle micr oscopy. UV-vis absorption spectra reveal that amphiphile 1 forms an ir reversible monolayer at the air-water interface due to its ''auto asse mbly''. The binding of BA molecules to a 2C(18)TAZ monolayer can be de tected by UV spectra at BA subphase concentrations as low as 0.01 mM. Different complementary hydrogen bonding additives in the subphase hav e different effects on the monolayer structure and properties of 1, wh ich are likely due to the different structures of hydrogen bonding add itives at the air-water interface. The effects of organic solvents in the subphase was also investigated. The strong solvating ability of di methyl sulfoxide (DMSO) destroyed the hydrogen bonding network whereas dioxane enhanced the hydrogen bonding between 1 and its hydrogen bond ing complements.