Binding potential and wetting behavior of binary liquid mixtures on surfaces.

Area of Science:

• Physical Chemistry
• Materials Science
• Surface Science

Background:

• Binary liquid mixtures exhibit complex bulk phase behavior influenced by interparticle interactions, temperature, and chemical potentials.
• Understanding interfacial wetting phenomena is crucial for predicting mixture behavior on solid substrates.
• Existing theories may not fully capture the diverse interfacial phase behaviors of both miscible and immiscible binary liquid mixtures.

Purpose of the Study:

• To present a comprehensive theory for the interfacial wetting phase behavior of binary liquid mixtures on rigid solid substrates.
• To calculate the binding potential as a function of adsorptions, fully describing interfacial thermodynamics.
• To explore the interplay between bulk phase behavior and substrate interactions.

Main Methods:

• Utilizing classical density functional theory to model binary liquid mixtures.
• Calculating the binding potential based on adsorptions (excess liquid amounts at the substrate).
• Analyzing liquid density profiles near the substrate under varying interaction parameters.

Main Results:

• The theory is applicable to both miscible and immiscible binary liquid mixtures.
• A wide variety of interfacial phase behaviors, including mixing and demixing, were predicted.
• Situations with coexistence of up to three different phases were identified.
• The binding potential can be a multivalued function of adsorptions, depending on interaction parameters.

Conclusions:

• The interplay between bulk properties and substrate interactions dictates complex interfacial phase behavior.
• The developed theory provides a robust framework for understanding and predicting interfacial thermodynamics of binary liquid mixtures.
• The findings are relevant for systems ranging from simple liquid mixtures to sessile droplets.