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Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals
Published on: May 25, 2016
Nematic and almost-tetratic phases of colloidal rectangles
Kun Zhao1, Christopher Harrison, David Huse
1Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 13, 2007
Summary
Researchers observed a novel liquid crystal phase in hard rectangles. Short-range tetratic correlations unexpectedly dominated over nematic correlations near the isotropic-nematic transition.
Area of Science:
- Colloid science
- Soft matter physics
- Materials science
Background:
- Nonspherical colloids form liquid-crystalline phases with varying symmetry.
- Understanding phase transitions in these systems is crucial for materials design.
Purpose of the Study:
- Investigate the liquid-crystalline phases of hard rectangles.
- Characterize the nature of phase transitions, particularly near the isotropic-nematic transition.
Main Methods:
- Utilized photolithographically prepared disks standing on edge to create hard rectangles.
- Observed and analyzed the behavior of these colloids under varying densities.
Main Results:
- A conventional Kosterlitz-Thouless transition from isotropic to nematic phase was observed.
- An unusual regime with dominant short-range tetratic correlations was found on the isotropic side of the transition.
- This regime is attributed to Ising-like $\pi/2$ grain boundaries disrupting nematic order while preserving tetratic correlations.
Conclusions:
- Hard rectangles exhibit complex liquid-crystalline behavior beyond conventional nematic and smectic phases.
- The identified unusual regime highlights new possibilities for controlling material properties through colloidal shape and interactions.
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