Dynamic behavior of pyramidic liquid crystal film at the air-water interface

Molecular organization of the different phases of a pyramidic liquid crystal film spread at the air-water interface has been investigated using Langmuir balance and current displacement techniques simultaneously. The mesogenic compound exhibits a main transition from an expanded phase to a metastable condensed phase. The results are in agreement with previous polarized and fluorescence light microscopy measurements and grazing incidence X-ray reflectometry. The study shows that the molecules are oriented edge-on in the condensed phase and side-on in the liquid expanded phase. The value of the dipole moment of the pyramidic molecules is given in the liquid expanded phase. Two kinds of displacement current curves were obtained depending on the kinetic of compression.