Wetting and cavitation pathways on nanodecorated surfaces

Area of Science:

• Physics
• Materials Science
• Chemistry

Background:

• Superhydrophobicity relies on surface nanostructure to trap vapor.
• Understanding the stability of this vapor phase is critical for submerged applications.

Purpose of the Study:

• Investigate vapor bubble nucleation and wetting on nanodecorated surfaces.
• Determine the stability limits of the Cassie state under varying pressures.

Main Methods:

• Free energy molecular dynamics simulations.
• Rare event techniques to study wetting and cavitation pathways.
• Atomistic simulations of nanometric systems.

Main Results:

• Re-entrant surface geometry sustains confined vapor (Cassie state).
• Free energy barriers for wetting and cavitation are pressure-dependent, around 100kBT.
• Atomistic results align with macroscopic capillarity theory but capture spinodal instability.

Conclusions:

• Nanostructured surfaces can stabilize superhydrophobicity via confined vapor.
• Complex pathways and significant energy barriers govern wetting and cavitation.
• Molecular dynamics provides insights beyond classical capillarity theory for nanoscale phenomena.