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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Chiral isotropic liquids from achiral molecules.
L E Hough1, M Spannuth, M Nakata
1Department of Physics and Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA. hough@colorado.edu
Science (New York, N.Y.)
|July 25, 2009
Summary
Simple bent-core molecules form unique liquid crystal phases. Despite being achiral, these phases exhibit spontaneous chirality and high optical rotatory power due to layer instability.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Chemistry
Background:
- Bent-core molecules can form liquid crystal phases with unique properties.
- Smectic liquid crystals typically exhibit planar fluid layers.
- Spontaneous polarization and chirality are unusual in achiral molecules.
Purpose of the Study:
- To investigate the liquid crystal phases formed by simple bent-core molecules.
- To understand the origin of spontaneous polarization and chirality in these phases.
- To characterize the stability and symmetry breaking in these molecular systems.
Main Methods:
- Synthesis and characterization of bent-core molecules.
- Microscopy and X-ray diffraction to study liquid crystal phases.
- Optical measurements to determine rotatory power.
Main Results:
- Bent-core molecules form smectic liquid crystal phases with planar fluid layers.
- Intralayer structural mismatch leads to instability against saddle splay deformation.
- Macroscopically isotropic fluids with short-range order and spontaneous chirality are formed.
- High optical rotatory powers were observed in conglomerate domains.
Conclusions:
- Bent-core molecules can exhibit spontaneous chirality and polarization without crystalline order.
- Layer instability dictates the macroscopic properties, leading to isotropic fluids with broken symmetry.
- These findings offer new insights into the relationship between molecular structure and macroscopic properties in liquid crystals.
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