Vapor nucleation paths in lyophobic nanopores

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Lyophobic nanopores are crucial for energy storage and dissipation.
• Heterogeneous lyophobic systems (HLS) leverage nanoporous materials and non-wetting liquids.
• Liquid behavior in nanopores depends on microscopic details and hysteresis.

Purpose of the Study:

• To investigate vapor bubble nucleation within lyophobic mesopores using atomistic simulations.
• To understand the influence of pore geometry and liquid interactions on nucleation pathways.
• To compare simulation results with continuum models for mesoporous materials.

Main Methods:

• Advanced atomistic simulation techniques were employed.
• The string method in collective variables was used to overcome computational challenges of activated nucleation.
• Free-energy landscapes and nucleation paths were analyzed.

Main Results:

• Multiple independent nucleation paths with distinct free-energy barriers were identified.
• Asymmetric bubble nucleation paths, forming at pore walls, were found to be more probable than axisymmetric paths.
• Nanoscale effects in 4nm mesopores showed a minor role compared to smaller pores.

Conclusions:

• Atomistic simulations provide detailed insights into nucleation phenomena in confined systems.
• Asymmetric nucleation pathways dominate the process in lyophobic mesopores.
• Macroscopic nucleation theories offer a qualitative agreement with atomistic findings for mesoporous materials.