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Liquid Crystals at Interfaces
Author(s) -
Gupta Raj Kumar,
Manjuladevi V.
Publication year - 2012
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201200030
Subject(s) - monolayer , chemistry , langmuir , brewster's angle , molecule , liquid crystal , chemical physics , intermolecular force , phase (matter) , langmuir–blodgett film , adsorption , crystallography , analytical chemistry (journal) , organic chemistry , optics , brewster , biochemistry , physics
The ordering in liquid crystals (LCs) can be influenced by an interface. Some of these molecules adsorbed at the air‐water interface yield a stable Langmuir monolayer. They exhibit numerous surface phases, which are classified on the basis of intermolecular separation and ordering. These surface phases are governed by the molecular interactions and the ambient experimental conditions such as temperature, humidity, pH, and ion content of the subphase. In this article, the role of molecular interactions on the surface behavior of several rodlike LCs are discussed. The Langmuir monolayer of a cholesteric LC exhibits an interesting low density liquid ( L 1′ ) phase with tilted molecules. Brewster angle microscopy reveals stripe patterns, which arise due to the precession of the tilted molecules. It is demonstrated that this molecular precession can be controlled by the relative humidity, presence of cations in the subphase, and incorporation of appropriate molecular species. The Langmuir monolayer and Langmuir‐Blodgett films of a novel rod‐disc hybrid LC are discussed.