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Dynamical phase of driven colloidal systems with short-range attraction and long-range repulsion.
Jiang-Xing Chen1, Jun-Wen Mao, Snigdha Thakur
1Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China. jxchen@hdu.edu.cn
The Journal of Chemical Physics
|September 15, 2011
Summary
Increasing temperature melts colloidal clusters, while stronger repulsion causes a depinning transition. Disorder from the substrate leads to cluster polarization under external force.
Area of Science:
- Soft matter physics
- Colloidal systems
- Non-equilibrium dynamics
Background:
- Colloidal systems exhibit complex behavior influenced by interparticle forces and substrate interactions.
- Understanding non-equilibrium dynamics is crucial for predicting material properties under external stimuli.
- Disordered substrates introduce heterogeneity affecting particle assembly and flow.
Purpose of the Study:
- To investigate the non-equilibrium dynamics of colloidal systems with competing interactions on a disordered substrate.
- To characterize the temperature-induced growth-melting transition and the effect of electrostatic repulsion on cluster dynamics.
- To map the phase diagram and explore the influence of disorder and external forces on colloidal assembly.
Main Methods:
- Simulation of colloidal particles with short-range depletion attraction and screened electrostatic repulsion.
- Analysis of cluster formation, melting, and depinning transitions.
- Characterization of orientational and translational order under external forces and varying substrate disorder.
Main Results:
- A temperature-driven growth-melting process for colloidal clusters was observed.
- A depinning transition from moving clusters to plastic flow was identified by increasing screened electrostatic repulsion, marked by a peak in depinning force.
- Under strong external force, substrate disorder induced cluster polarization, leading to orientational order parallel and translational order perpendicular to the force.
Conclusions:
- The study reveals distinct phase transitions and ordering phenomena in colloidal systems driven by temperature, interparticle forces, and substrate disorder.
- The findings highlight the significant role of electrostatic repulsion and substrate heterogeneity in controlling colloidal dynamics and assembly.
- The observed polarization and ordering under external force provide insights into the behavior of soft matter in complex environments.
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