Fatty Acid Langmuir Films on Liquid Mercury: X-ray and Surface Tension Studies

 Title: Fatty Acid Langmuir Films on Liquid Mercury: X-ray and Surface Tension Studies Author: Kraack, H.; Ocko, B. M.; Pershan, Peter S.; Sloutskin, E.; Tamam, L.; Deutsch, M. Note: Order does not necessarily reflect citation order of authors. Citation: Kraack, H., B. M. Ocko, Peter S. Pershan, E. Sloutskin, L. Tamam, and M. Deutsch. 2004. Fatty acid Langmuir films on liquid mercury: X-ray and surface tension studies. Langmuir 20(13): 5375-5385. Access Status: Full text of the requested work is not available in DASH at this time (“dark deposit”). For more information on dark deposits, see our FAQ. Full Text & Related Files: Kraack_Fatty.pdf (271.1Kb; PDF) Abstract: The structure and phase behavior of liquid-mercury-supported molecular films of fatty acids ($$CH_{3}(CH_{2})_{n-2}COOH$$,denoted CnOOH) were studied for molecular lengths 7 $$\leq$$ n $$\leq$$ 24, by surface tensiometry and X-ray methods. Two qualitatively different film structures were found, depending on coverage. For high coverage, the film consists of a monolayer of roughly surface-normal molecules, showing a pressure-dependent sequence of structures similar, though not identical, to that of the corresponding water-supported Langmuir films. At low coverage, phases consisting of surface-parallel molecules are found, not observed on the aqueous subphases employed to date. In this range, a two-dimensional (2D) gas followed by a single and, for 14 $$\leq$$ n $$\leq$$ 24, also by a double layer of surface-parallel molecules is found as coverage is increased. Depending on chain length, the flat-lying phases have a crystalline 2D ordered, a smectic-like 1D-ordered, or a disordered in-plane structure consisting of molecular dimers. The structure and thermodynamics of the films are discussed. Published Version: doi:10.1021/la049977y Other Sources: http://www.liquids.deas.harvard.edu/peter/2004.pdf/fattyacids_aspublished.pdf Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10354248 Downloads of this work: