Adsorption of Fluids in Pores Formed between Two Hard Cylinders.

Area of Science:

• Physical Chemistry
• Materials Science
• Thermodynamics

Background:

• Understanding fluid behavior in confined geometries is crucial for materials science and chemical engineering.
• Pore geometry significantly influences adsorption and phase behavior.
• Density functional theory (DFT) is a powerful tool for studying confined fluids.

Purpose of the Study:

• To investigate adsorption of hard spheres and Lennard-Jones fluids in pores with curved hard walls.
• To compare adsorption in curved pores with that in slitlike pores.
• To analyze the effect of pore curvature on capillary evaporation and phase diagrams.

Main Methods:

• Utilizing a density functional approach to model adsorption.
• Comparing DFT results for hard spheres with grand canonical ensemble Monte Carlo simulations.
• Evaluating adsorption isotherms and phase behavior for different pore geometries.

Main Results:

• The DFT approach accurately reproduces fluid structure compared to Monte Carlo simulations.
• Adsorption in curved pores is comparable to slitlike pores with similar dimensions.
• Pore wall curvature shifts capillary evaporation transitions to lower chemical potentials.
• Critical temperature for Lennard-Jones fluids is slightly increased in curved pores compared to slit pores.

Conclusions:

• Density functional theory is a reliable method for studying confined fluids.
• Pore curvature has a minor impact on overall adsorption but influences phase transition thermodynamics.
• Findings provide insights into fluid behavior in nanoporous materials with varying geometries.