Interfacial tension of solid materials against dense carbon dioxide

Area of Science:

• Surface Science
• Materials Science
• Physical Chemistry

Background:

• The Young equation relates interfacial tensions and contact angles but has four unknowns.
• Only liquid interfacial tension (sigma lv) and contact angle (theta) are directly measurable.
• A theoretical approach to determine solid interfacial tension (sigma sv) and solid-liquid interfacial tension (sigma sl) is needed.

Purpose of the Study:

• To theoretically calculate the solid interfacial tension (sigma sv) for materials like PTFE, steel, and glass.
• To validate the calculated sigma sv values using different liquid systems (dense CO2, aqueous, ethanolic).
• To assess the potential of using calculated sigma sv for theoretical prediction of contact angles (theta).

Main Methods:

• Utilizing Good's parameter (Phi sl) based on intermolecular interactions to estimate sigma sv.
• Calculating sigma sv for PTFE, steel, and glass in dense carbon dioxide.
• Comparing calculated sigma sv values with those derived from aqueous and ethanolic systems.
• Forecasting water drop contact angles (theta) using the calculated sigma sv and comparing with experimental data.

Main Results:

• Successful calculation of solid interfacial tension (sigma sv) for selected materials.
• Verification of calculated sigma sv values across different liquid environments.
• Demonstrated correlation between calculated sigma sv and experimentally measured contact angles (theta).

Conclusions:

• The proposed method provides a theoretical pathway to determine solid interfacial tension (sigma sv).
• This approach offers a viable alternative for estimating contact angles (theta) without direct experimental measurement.
• Understanding sigma sv is crucial for solving the Young equation and advancing interfacial science.