Related Experiment Video
Updated: Aug 5, 2025
07:56
Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light
Published on: September 20, 2017
11.7K
Strategies for promoting discotic nematic phases
Carson O Zellman1, Vance E Williams1
1Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. vancew@sfu.ca.
Soft Matter
|March 29, 2023
Summary
Researchers synthesized discotic dimers to achieve nematic discotic liquid crystal phases. Bulky groups and mixed-length peripheral chains successfully promoted an enantiotropic nematic phase in these liquid crystals.
Area of Science:
- Materials Science
- Organic Chemistry
- Crystallography
Background:
- Discotic liquid crystals exhibit unique self-assembly properties.
- Nematic discotic phases are challenging to obtain due to molecular structural requirements.
Purpose of the Study:
- To synthesize novel discotic dimers.
- To investigate the formation of nematic discotic liquid crystal phases.
Main Methods:
- Synthesis of discotic dimers with specific structural modifications.
- Incorporation of bulky groups adjacent to ester bridges.
- Utilizing peripheral chains of mixed lengths.
Main Results:
- Initial target compounds were nonmesogenic.
- Modified compounds successfully formed an enantiotropic nematic phase.
- Structural modifications were key to promoting liquid crystal phase formation.
Conclusions:
- Discotic dimers can be engineered to exhibit nematic phases.
- Steric hindrance and peripheral chain engineering are critical factors.
- Successful synthesis provides a route to novel liquid crystalline materials.
Related Concept Videos
01:26Phase Contrast and Differential Interference Contrast Microscopy
8.3K
Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
8.3K
01:19Phase Diagram
6.0K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
6.0K
02:39Phase Diagrams
42.1K
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...
42.1K
02:31Phase Transitions
19.3K
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...
19.3K
02:33Phase Transitions: Sublimation and Deposition
17.3K
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...
17.3K
02:39Phase Transitions: Melting and Freezing
12.5K
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...
12.5K