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Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
Published on: May 20, 2014
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Shape-designed frustration by local polymorphism in a near-equilibrium colloidal glass
1Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095; Department of Physics and Astronomy, University of California, Los Angeles, CA 90095; Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China kunzhao@tju.edu.cn mason@chem.ucla.edu.
Summary
Hard, convex kite platelets form a stable 2D colloidal glass, unlike other shapes. This robust glass-forming tendency is due to diverse local configurations, preserving disorder even at high densities.
Area of Science:
- Soft Matter Physics
- Materials Science
- Crystallography
Background:
- Two-dimensional (2D) systems of hard particles are crucial for understanding phase transitions and material properties.
- Crystallization is a common behavior in 2D systems of convex shapes at high densities.
- Colloidal glasses represent a disordered, non-equilibrium state of matter.
Purpose of the Study:
- To investigate the self-assembly and phase behavior of lithographic kite platelets in a 2D monolayer.
- To determine if kite particles exhibit distinct self-assembly properties compared to other convex shapes.
- To understand the mechanisms behind the formation of arrested disordered states in 2D systems.
Main Methods:
- Quasi-static concentration of hard, convex, lithographic, prismatic kite platelets in a monolayer.
- Observation of particle dynamics under thermal Brownian fluctuations.
- Analysis of long-time translational and rotational diffusion to identify glass formation.
Main Results:
- Kite platelets preferentially form a disordered and arrested 2D glass at high densities.
- Unlike squares, rhombs, and pentagons, kites resist crystallization.
- The glass state is characterized by bounded diffusion and diverse local polymorphic configurations (LPCs).
Conclusions:
- The unique geometry of 72° kites drives robust 2D glass formation.
- Competition between diverse LPCs with incommensurate features hinders crystallization.
- Entropy maximization is compatible with the preservation of diverse local structures in the arrested glass state.
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