Related Experiment Video
Updated: Aug 14, 2026

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Disjoining pressure and thinning transitions in smectic-A liquid crystal films
1Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
Abstract:
The contact angle between a free standing film of a smectic-A liquid crystal and its meniscus is different from zero. It increases independently of the meniscus size when the film thickness decreases. This angle provides a very precise measurement of the film tension and of the interactions between the two free surfaces. This interaction is attractive and can be qualitatively explained within the framework of the de Gennes theory of the presmectic state. According to this model, the attraction is caused by an increase of the smectic order parameter at the free surface. This phenomenon also explains the metastability of very thin smectic films above the bulk smectic-A-nematic phase transition. The temperatures T(N) of spontaneous thinning from N layers to N-1 layers is measured in the smectic phase of the liquid crystal 8CB (octylcyanobiphenyl).
Related Concept Videos
Fluid Mosaic Model
Phase Transitions: Melting and Freezing
Molecular and Ionic Solids
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Fluid Mosaic Model
Intermolecular Forces and Physical Properties
Solid–Solid Solutions

