Modeling Disjoining Pressures in Submicrometer Liquid-Filled Cylindrical Geometries

Area of Science:

• Physical Chemistry
• Materials Science
• Chemical Engineering

Background:

• Disjoining pressure is crucial for understanding fluid behavior in confined geometries.
• Existing models primarily focus on slit-like pores, limiting applicability to cylindrical systems.
• Submicrometer cylindrical pores are relevant in membrane filtration and fluid dynamics.

Purpose of the Study:

• To develop and validate models for calculating disjoining pressures in submicrometer cylindrical pores.
• To compare the magnitude of disjoining pressures in cylindrical versus slit-pore models.
• To explore the implications of these models for mass transport in porous media.

Main Methods:

• Development of closed-form analytical models for London/van der Waals and adsorption interactions.
• Numerical solution for electrostatic interactions in cylindrical pores.
• Comparison of cylindrical pore models with established slit-pore models.

Main Results:

• Cylindrical-pore models predict significantly higher disjoining pressures (48-fold or more for van der Waals/adsorption) compared to slit-pore models.
• Numerical solutions for electrostatic interactions show a 9-fold increase in disjoining pressure.
• The developed models provide a more accurate thermodynamic description for fluids in cylindrical nanopores.

Conclusions:

• The derived cylindrical models offer a more realistic representation of disjoining pressures in submicrometer pores.
• These findings have direct implications for understanding and optimizing mass transport in ultrafiltration, nanofiltration, and reverse-osmosis membranes.
• The models can be extended to various applications involving fluid interfaces in cylindrical confinement.