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Interplay between columnar and smectic stability in suspensions of polydisperse colloidal platelets
Enrique Velasco1, Yuri Martínez-Ratón
1Departamento de Física Teórica de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain. enrique.velasco@uam.es.
Physical Chemistry Chemical Physics : PCCP
|November 26, 2013
Summary
This study models colloidal platelet suspensions, revealing how variations in platelet length and height influence phase behavior. The findings show that specific polydispersities stabilize distinct phases like smectic and columnar structures.
Area of Science:
- Colloid Science
- Materials Science
- Statistical Mechanics
Background:
- Colloidal suspensions of anisotropic particles exhibit complex phase behavior.
- Understanding these phases is crucial for designing advanced materials.
- Platelet-shaped colloids are of particular interest due to their unique ordering properties.
Purpose of the Study:
- To investigate the phase behavior of a model suspension of polydisperse platelets.
- To determine the influence of length and height polydispersities on phase stability.
- To explore the formation of nematic, smectic, and columnar phases.
Main Methods:
- Density-functional theory was employed to model platelet suspensions.
- Platelets were represented as rectangular prisms with square sections.
- Length and height distributions were characterized by polydispersities δ(l) and δ(h).
Main Results:
- The study mapped the phase behavior, including nematic, smectic, and columnar phases.
- Phase stability was found to depend significantly on the ratios of δ(l) and δ(h).
- Microsegregation effects were observed in both smectic and columnar phases.
Conclusions:
- The relative polydispersities of platelet length and height dictate the preferred phase (smectic vs. columnar).
- Asymmetric stability regions for smectic and columnar phases were observed in the δ(l)-δ(h) plane.
- The findings provide insights into the self-assembly of anisotropic colloidal systems.
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