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Roughness-induced filling.
1Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, Hoza 69, 00-681 Warszawa, Poland.
Summary
Substrate corrugation does not alter wetting transitions for critical wetting fluids. However, it can drive a new first-order phase transition, leading to a thin-thick interface, especially with short-range interactions.
Area of Science:
- Physical Chemistry
- Surface Science
- Thermodynamics
Background:
- Understanding fluid adsorption on surfaces is crucial for various applications.
- Wetting phenomena and phase transitions are fundamental concepts in surface science.
- Periodic corrugations on substrates can significantly alter adsorption behavior compared to planar surfaces.
Purpose of the Study:
- To investigate the effect of substrate corrugation on fluid adsorption and wetting transitions.
- To analyze the influence of corrugation amplitude and interaction range on the system's free energy.
- To determine the phase diagram for fluid adsorption on a sinusoidally corrugated substrate.
Main Methods:
- Utilizing the mean-field version of the effective Hamiltonian approach.
- Analyzing the interface shape near the wetting point of a planar substrate.
- Calculating the free energy as a function of temperature and corrugation amplitude.
Main Results:
- Substrate roughness does not affect the wetting transition locus or order under critical wetting conditions.
- A corrugation-driven filling transition is observed for short-range interactions.
- A critical corrugation amplitude induces a first-order thin-thick transition.
Conclusions:
- Periodic corrugations can introduce novel phase transitions not present on flat surfaces.
- The study provides a comprehensive phase diagram for adsorption on corrugated substrates.
- Findings are relevant for designing surfaces with controlled fluid interactions.