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Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
Columnar versus smectic order in systems of charged colloidal rods.
1Institut für Theoretische Physik, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany. wensink@thphy.uni-duesseldoerf.de
The Journal of Chemical Physics
|May 26, 2007
Summary
We investigated the stability of charged rod liquid crystals. Columnar order becomes more stable than smectic order as screening length increases, contrary to expectations in strongly screened systems.
Area of Science:
- Condensed matter physics
- Soft matter physics
- Theoretical chemistry
Background:
- Liquid crystals exhibit diverse phases like nematic, smectic, and columnar.
- Charged rod systems are sensitive to electrostatic interactions and screening effects.
- Understanding phase transitions is crucial for materials science and nanotechnology.
Purpose of the Study:
- To analyze the stability of inhomogeneous liquid crystalline states in monodisperse, stiff, charged rod systems.
- To investigate the influence of Debye screening length on nematic-smectic and nematic-columnar instabilities.
- To compare theoretical predictions with Brownian dynamics simulations.
Main Methods:
- Bifurcation analysis of the Onsager free energy for charged rods.
- Investigation of stability as a function of Debye screening length (kappa(-1)).
- Brownian dynamics computer simulations using the Yukawa site model.
Main Results:
- Nematic-smectic transition precedes nematic-columnar transition under strong screening (small kappa(-1)).
- Hexagonal columnar order exhibits enhanced stability at larger screening lengths.
- Theoretical findings are corroborated by simulation results.
Conclusions:
- The stability of liquid crystalline phases in charged rod systems is strongly dependent on screening length.
- Columnar phases can be stabilized over smectic phases in less screened environments.
- Findings are relevant to tobacco mosaic virus rods and other soft rodlike mesogens in external fields.
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