Interfacial tensions and viscosities in multiphase systems by surface light scattering (SLS)

Area of Science:

• Process Engineering
• Physical Chemistry
• Materials Science

Background:

• Multiphase systems are crucial in process engineering, requiring accurate thermophysical property data.
• Literature often lacks essential data on viscosity and interfacial tension for these systems.
• Accurate property data is vital for effective process and product design.

Purpose of the Study:

• To demonstrate the applicability of surface light scattering (SLS) for simultaneous measurement of interfacial tensions and viscosities.
• To determine thermophysical properties in multiphase systems at thermodynamic equilibrium.
• To provide accurate data for model systems relevant to process design.

Main Methods:

• Utilized surface light scattering (SLS) to analyze surface fluctuations.
• Investigated two model systems: n-decane/methanol and n-dodecane/methanol at vapor-liquid-liquid equilibrium.
• Employed theoretical description of surface fluctuation dynamics to extract property data.

Main Results:

• Successfully measured dynamic viscosities and interfacial tensions for vapor-liquid and liquid-liquid interfaces.
• Achieved high accuracy (total measurement uncertainties down to ~2%) between 333 K and 358 K.
• Observed viscosity convergence and interfacial tension approaching zero near the upper critical solution temperature.

Conclusions:

• SLS is a viable technique for simultaneous determination of interfacial tensions and viscosities in multiphase systems.
• The study provides essential thermophysical data for n-alkane/methanol systems.
• Findings are significant for understanding phase behavior near critical points in process engineering.