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Structural and dynamical analysis of monodisperse and polydisperse colloidal systems
Marianna Yiannourakou1, Ioannis G Economou, Ioannis A Bitsanis
1Molecular Thermodynamics and Modeling of Materials Laboratory, Institute of Physical Chemistry, National Center for Scientific Research Demokritos, GR-153 10 Aghia Paraskevi Attikis, Greece.
The Journal of Chemical Physics
|December 22, 2010
Summary
Polydisperse soft spheres exhibit enhanced crystal order compared to monodisperse systems, though softness degrades crystallinity. Diffusion in crystals is robust, while amorphous suspensions show delayed diffusion due to overcrowding.
Area of Science:
- Soft matter physics
- Computational condensed matter physics
- Statistical mechanics
Background:
- Understanding the relationship between particle interactions and macroscopic properties is crucial.
- Polydispersity, the distribution of particle sizes, significantly influences system behavior.
- Soft potentials allow for tunable interactions and diverse phase behaviors.
Purpose of the Study:
- To investigate structural and dynamical properties of polydisperse soft spheres.
- To compare crystalline and amorphous phases at coexistence.
- To analyze the impact of potential softness on system order and dynamics.
Main Methods:
- Semigrand ensemble Monte Carlo simulations.
- Brownian dynamics simulations.
- Detailed structural analysis and diffusion measurements.
Main Results:
- Crystallinity deteriorates as potential interactions soften.
- Polydisperse crystals are generally more ordered than monodisperse ones.
- Softer potentials lead to substitutionally disordered crystals, while hard-sphere interactions maintain order.
- Diffusion in crystals is robust, with minor differences in vibrational amplitudes.
- Amorphous polydisperse suspensions exhibit delayed diffusion at intermediate times due to overcrowding.
Conclusions:
- Particle size distribution and interaction softness are key determinants of soft matter phase behavior.
- Polydispersity can enhance crystal order under specific conditions.
- Dynamics are significantly affected by phase state and particle interactions.
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