COLL 356 |
| Henning Kraack1, E Sloutskin1, M Deutsch1, Benjamin M. Ocko2, and Peter Pershan3. (1) Physics Department, Bar-Ilan University, Ramat Gan, Israel, (2) Physics Department, Brookhaven National Laboratory, Upton, NY 11973, (3) Physics Dept, Harvard University, Cambridge, MA |
| The structure of organic monolayers on liquid surfaces depends sensitively on the details of the molecular interactions. The structure of a stearic acid film on a mercury surface was studied as a function of coverage by pressure/area isotherms and Ångström-resolution x-ray grazing angle diffraction and reflectivity measurements[1]. Unlike monolayers on water, the molecules are found here to undergo a transition from surface-parallel to surface-normal orientation with increasing coverage. At high coverage, two condensed hexatic phases of standing-up molecules were found. At low coverage, a 2D gas phase and condensed single- and double-layered phases of flat-lying molecular dimers were discovered, exhibiting a 1D longitudinal positional order. The variation of the structure with chain length, and results for n-alkanes and n-alcohols will be also presented. [1] H. Kraack et al., Science 298, 141 (2002) |
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Adamson Award Symposium Honoring Dave Allara and Ralph Nuzzo
Division of Colloid and Surface Chemistry |