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Mesophase behaviour of polyhedral particles.
Umang Agarwal1, Fernando A Escobedo
1School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA.
Nature Materials
|February 15, 2011
Summary
Entropy-driven assembly of anisotropic particles forms ordered structures. Simulations of polyhedrons reveal guidelines for predicting liquid-crystalline and plastic-crystalline phases based on symmetry and anisotropy.
Area of Science:
- Materials Science
- Statistical Physics
- Crystallography
Background:
- Anisotropic particles can self-assemble into ordered structures driven by entropy.
- Understanding the relationship between particle shape, symmetry, and resulting phases is crucial for materials design.
Purpose of the Study:
- To investigate the entropy-driven assembly of six convex space-filling polyhedrons.
- To establish guidelines for predicting the phase behavior of polyhedral particles based on their properties.
Main Methods:
- Detailed Monte Carlo simulations were performed on six types of polyhedral particles.
- Correlations between particle anisotropy, rotational symmetry, and emergent mesophases were analyzed.
Main Results:
- New liquid-crystalline and plastic-crystalline phases were predicted at intermediate volume fractions.
- Guidelines were proposed: high symmetry favors mesophase formation, low anisotropy favors plastic solids, and intermediate anisotropy favors liquid crystals.
- Dynamical disorder was identified as critical for mesophase behavior.
Conclusions:
- Particle anisotropy and rotational symmetry are key determinants of self-assembly into ordered phases.
- The kinetic barrier for liquid-crystal formation is lower than for plastic-solid formation.
- Predictive guidelines can aid in designing materials with desired self-assembled structures.
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