Structure of a Langmuir Film on a Liquid Metal Surface
H. Kraack,1
B. M. Ocko,2
P. S. Pershan,3
E. Sloutskin,1
M. Deutsch1*
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 measured as a function
of coverage with angstrom resolution. Unlike monolayers on water, the
molecules were 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 two-dimensional (2D) gas phase and condensed
single- and double-layered phases of flat-lying molecular dimers were
revealed, exhibiting a 1D longitudinal positional order. This system
should provide a broader tunability range for nanostructure
construction than solid-supported self-assembled monolayers.
1 Physics Department, Bar-Ilan University, Ramat Gan
52900, Israel.
2 Physics Department, Brookhaven National
Laboratory, Upton, NY 11973, USA.
3 Physics Department and
Division of Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
*
To whom correspondence should be addressed. E-mail:
deutsch{at}mail.biu.ac.il
