Langmuir films of normal-alkanes on the surface of liquid mercury

H. Kraack, B. M. Ocko, P. S. Pershan, E. Sloutskin, M. Deutsch
2003 Journal of Chemical Physics  
The coverage dependent phase behavior of molecular films of n-alkanes (CH 3 CH nϪ2 CH 3 , denote Cn) on mercury was studied for lengths 10рnр50, using surface tensiometry and surface x-ray diffraction methods. In contrast with Langmuir films on water, where roughly surface-normal molecular orientation is invariably found, alkanes on mercury are always oriented surface-parallel, and show no long-range in-plane order at any surface pressure. At a low coverage a two-dimensional gas phase is found,
more » ... followed, upon increasing the coverage, by a single condensed layer (n р18), a sequence of single and double layers (19рnр20; nу26), or a sequence of single, double, and triple layers (22рnр24). The thermodynamical and structural properties of these layers, as determined from the measurements, are discussed.
doi:10.1063/1.1618211 fatcat:5r4tswlvmvb2rkatxtejzq6dxa