https://doi.org/10.1007/s100510050612
Quantitative Brewster angle microscopy measurements of chiral symmetry breaking and chiral boundaries in fatty acid Langmuir monolayers
Institute of Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany
Received:
26
January
1998
Revised:
3
August
1998
Accepted:
7
August
1998
Published online: 15 January 1999
Brewster angle microscopy (BAM) measurements of the low temperature region of the
phase diagram of eicosanoic acid monolayers at an acidic subphase are performed. The
existence of a new chiral I phase intervening between the L2 and 
phase
recently discovered by Durbin et al. [M.K. Durbin, A. Malik, A.G. Richter,
R. Ghastkadvi, T. Gog, P. Dutta, J. Chem. Phys. 106, 8216 (1997)] using grazing
incidence X-ray diffraction (GIXD) is confirmed. Chiral symmetry breaking within the
monolayers creates characteristic boundaries separating domains of opposite
handedness. These disclination lines are associated with a jump in the tilt azimuth of
the director, while the underlying hexatic orientation is continuous across the
boundary. The disclination lines are observed with the Brewster angle microscope and
analyzed as a function of surface pressure. The jump in tilt azimuth is determined.
Agreement with an extended Landau theory proposed by Durbin is achieved.
PACS: 68.10.-m – Fluid surfaces and fluid-fluid interfaces
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
