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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
The phase dynamics and wetting layer formation mechanisms in two-step surface-directed spinodal decomposition
1Advanced Materials Laboratory, Department of Chemical Engineering, Tsinghua University, Beijing, PR China. li-tang.yan@uni-bayreuth.de
The Journal of Chemical Physics
|April 25, 2008
Summary
Surface-directed spinodal decomposition was numerically studied. A two-step quench process influences wetting layer formation and domain structure, altering growth laws based on quench depths.
Area of Science:
- Materials Science
- Computational Physics
Background:
- Surface-directed spinodal decomposition (SDSD) is crucial for creating nanostructured materials.
- Understanding the phase dynamics of wetting layers in SDSD is essential for material design.
Purpose of the Study:
- To numerically investigate the two-step quench process in SDSD.
- To analyze the phase dynamics and formation mechanisms of wetting layers under varying quench conditions.
Main Methods:
- Coupling the Flory-Huggins-de Gennes equation with the Cahn-Hilliard-Cook equation.
- Numerical simulations to model the evolution of phase separation.
Main Results:
- A parallel strip structure forms and propagates into the bulk under specific shallow first quench conditions.
- The wetting layer's growth dynamics change from a time exponent of 1/2 to a constant state.
- Deeper second quenches promote secondary domain structures when initial bulk phase separation occurs, shifting wetting layer formation from logarithmic to Lifshitz-Slyozov growth.
Conclusions:
- The two-step quench strategy offers control over nanostructure formation in SDSD.
- Wetting layer formation mechanisms are sensitive to the interplay between initial and subsequent quench depths.
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