Related Experiment Video
Updated: Feb 4, 2026
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
7.6K
Emission ellipsometry as a tool for luminescent liquid crystal phase transition identification
Gustavo G Dalkiranis1,2, E M Therézio3, Gilmar Conte4
1Department of Physics, Universitat Autònoma de Barcelona, CP 08193, Bellaterra, Spain.
Physical Review. E
|September 27, 2018
Summary
This study investigates luminescent liquid crystals with smectic mesophases using emission ellipsometry. Photoselection and an empirical model correlate light polarization changes with phase transitions.
Area of Science:
- Materials Science
- Physical Chemistry
- Optics
Background:
- Liquid crystals exhibit unique optical properties crucial for display technologies.
- Luminescent molecules offer potential for advanced optical materials.
- Understanding molecular behavior during phase transitions is key to material design.
Purpose of the Study:
- To investigate the liquid crystalline properties of a specific luminescent molecule.
- To explore the utility of emission ellipsometry for studying such materials.
- To develop a model correlating optical properties with phase transitions.
Main Methods:
- Utilized emission ellipsometry to analyze the luminescent molecule.
- Employed photoselection of excitation light to enhance experimental accuracy.
- Developed and applied an empirical model to interpret experimental data.
Main Results:
- Observed distinct smectic mesophases in the luminescent molecule.
- Successfully correlated changes in Stokes parameters (polarization degree, ellipticity, rotation) with phase transitions.
- Demonstrated the effectiveness of the photoselection methodology.
Conclusions:
- Emission ellipsometry is a powerful tool for characterizing luminescent liquid crystals.
- The study provides insights into the relationship between molecular structure, optical properties, and phase behavior.
- The developed empirical model aids in understanding liquid crystal phase transitions.
Related Concept Videos
02:31Phase Transitions
23.2K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.2K
02:33Phase Transitions: Sublimation and Deposition
20.2K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.2K
02:39Phase Transitions: Melting and Freezing
15.2K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
15.2K
02:39Phase Transitions: Vaporization and Condensation
21.4K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
21.4K
02:39Emission Spectra
76.4K
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present.
76.4K
02:39Phase Diagrams
50.2K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
50.2K