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Liquid crystal phase behaviour of attractive disc-like particles
Liang Wu1, George Jackson, Erich A Müller
1Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. l.wu09@imperial.ac.uk
International Journal of Molecular Sciences
|August 23, 2013
Summary
We developed a new theory for attractive disc particles, revealing how attractive forces promote ordered phases. Interestingly, some disc fluids exhibit coexistence between two distinct nematic phases.
Area of Science:
- Thermodynamics
- Soft Matter Physics
- Materials Science
Background:
- Understanding the phase behavior of anisotropic particles is crucial for designing advanced materials.
- Attractive interactions significantly influence the formation of ordered phases in soft matter systems.
- Disc-like mesogens present unique challenges due to their shape and anisotropic interactions.
Purpose of the Study:
- To develop a theoretical framework describing the thermodynamic properties and orientational order of attractive disc particles.
- To investigate the fluid-phase behavior, including vapor-liquid and isotropic-nematic transitions.
- To explore the conditions leading to the coexistence of multiple nematic phases.
Main Methods:
- Utilizing a generalized van der Waals-Onsager perturbation theory to construct a free energy functional.
- Modeling disc particles with anisotropic square-well attractive potentials on hard cylindrical cores.
- Developing an algebraic equation of state using the Onsager trial function for orientational order.
Main Results:
- The theory successfully describes thermodynamic properties and orientational order for isotropic and nematic phases.
- Attractive interactions were found to facilitate the formation of orientationally-ordered phases compared to athermal systems.
- A novel coexistence between two anisotropic nematic phases was observed for specific molecular aspect ratios.
Conclusions:
- The developed theory provides a robust model for attractive disc particle systems.
- Attractive forces play a key role in driving the formation of complex liquid crystalline phases.
- The discovery of nematic-nematic coexistence opens new avenues for understanding anisotropic fluid behavior.
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