Thermodynamic Barrier for Nanoparticle Penetration into Nanotubes

Area of Science:

• Physical Chemistry
• Nanotechnology
• Materials Science

Background:

• Separating nanoparticles (NPs) using nanochannel devices presents significant challenges.
• Understanding the thermodynamic mechanisms governing NP behavior in nanochannels is crucial for developing effective separation techniques.

Purpose of the Study:

• To investigate the thermodynamic mechanism of nanoparticle penetration into solvent-filled nanotubes.
• To provide theoretical guidance for optimizing nanoparticle separation methods in microfluidic devices.

Main Methods:

• Classical density functional theory was employed to study nanoparticle penetration.
• The potential of mean force (PMF) was calculated to assess the thermodynamic energy barrier.
• Molecular dynamics simulations were used for theoretical validation.

Main Results:

• Nanotube size, solvent density, and substrate wettability significantly influence NP penetration.
• Larger tubes, lower bulk solvent density, and solvophilic substrates promote NP penetration.
• Hourglass-shaped entrances enhance NP penetration efficiency compared to square-shaped entrances.
• A minimum separation density was identified, below which additional driving force is needed for NP penetration.

Conclusions:

• The study provides fundamental insights into the thermodynamic barriers for NP penetration into nanotubes.
• Findings offer theoretical guidance for designing and improving nanoparticle separation in microfluidic systems.