Related Experiment Video
Updated: May 28, 2026
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
A self-quenched defect glass in a colloid-nematic liquid crystal composite
T A Wood1, J S Lintuvuori, A B Schofield
1Scottish Universities Physics Alliance and School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Kings Buildings, Mayfield Road, Edinburgh, EH9 3JZ, UK.
Science (New York, N.Y.)
|October 8, 2011
Summary
Researchers created strong soft solids using colloidal particles in liquid crystals. These materials form a unique 3D network of defect lines, acting like a self-organized glass.
Area of Science:
- Soft matter physics
- Materials science
- Liquid crystal science
Background:
- Colloidal particles in liquid crystals disrupt orientational order, forming defect lines called disclinations.
- The core of these disclinations exhibits a sharp decrease in orientational order.
Purpose of the Study:
- To investigate the mechanical properties of soft solids formed by high concentrations of colloidal particles in nematic liquid crystals.
- To understand the structural basis for the mechanical strength in these composite materials.
Main Methods:
- Dispersion of colloidal particles (volume fraction ≳ 20%) into a nematic liquid crystal.
- Characterization using confocal microscopy.
- Analysis through computer simulations.
Main Results:
- Discovery of soft solids with shear moduli up to 10(4) Pascals.
- Identification of a 3D percolated network of entangled defect lines and colloidal particles.
- Observation that this network is responsible for the material's mechanical strength.
Conclusions:
- The discovered soft solids exhibit significant mechanical strength due to a self-organized network of defect lines and particles.
- This structure is analogous to a "self-quenched glass," similar to the "vortex glass" state in type II superconductors.
Related Concept Videos
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
01:29Imperfections in Crystal Structure: Non-Stoichiometric Defects
Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...
01:25Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
01:29The Colloidal State
The formation of a colloidal system is exemplified by an aqueous solution containing Cl− ions is introduced to another containing Ag+ ions, resulting in the precipitation of solid AgCl as extremely tiny crystals. Instead of settling out as a filterable precipitate, these crystals remain suspended in the liquid, showcasing a colloidal system.A colloidal system involves colloidal particles within the approximate range of 1 to 1000 nm in at least one dimension, dispersed in a medium called the...
01:34The Fluid Mosaic Model
The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of membranes and serves as a foundation for future membrane-related studies. The model depicts the structure of the plasma membrane with a variety of components, which include phospholipids, proteins, and carbohydrates. These integral molecules are loosely bound, defining the cell’s border and providing fluidity for optimal function.