The relation between osmotic flow and tracer solvent diffusion for single-file transport.

Area of Science:

• Physical Chemistry
• Chemical Physics
• Nanopore Science

Background:

• Understanding solvent transport through confined geometries is crucial for various applications.
• Previous models often simplified or neglected intermolecular interactions within pores.
• The behavior of fluids at the nanoscale presents unique physical phenomena.

Purpose of the Study:

• To develop a general model for single-file solvent passage through ultra-narrow pores.
• To investigate the relationship between tracer diffusion and osmotic flow in such systems.
• To identify the role of solvent-solvent interactions in pore transport.

Main Methods:

• Development of a theoretical model for single-file solvent transport.
• Analysis of solvent partitioning into the pore.
• Calculation of diffusion rates within the pore.
• Comparison of tracer diffusion and osmotic flow under interaction effects.

Main Results:

• A general model demonstrates the equality of tracer diffusion and osmotic flow.
• Solvent-solvent interactions within the pore exactly compensate effects on partitioning and diffusion.
• Previous models are shown to be valid only in the absence of these interactions.

Conclusions:

• Solvent-solvent interactions are critical for accurately describing transport in ultra-narrow pores.
• The equality of tracer diffusion and osmotic flow is a fundamental consequence of these interactions.
• This work provides a more comprehensive understanding of nanoscale fluid dynamics.