Interface dynamics of microscopic cavities in water.

Area of Science:

• Physical Chemistry
• Nanotechnology
• Computational Fluid Dynamics

Background:

• Understanding the dynamics of nanoscale cavities is crucial for various applications, including drug delivery and materials science.
• Existing models often struggle to accurately capture the complex interplay between interfacial phenomena and solvent behavior at the nanoscale.

Purpose of the Study:

• To develop an analytical model for the interface motion of collapsing nanometer-sized spherical cavities in water.
• To validate the analytical model against explicit solvent molecular dynamics simulations.
• To investigate the influence of solvent properties and curvature effects on cavity collapse dynamics.

Main Methods:

• Modification of the Rayleigh-Plesset equation to describe cavity interface motion.
• Explicit solvent molecular dynamics simulations to model water behavior at the nanoscale.
• Comparative analysis of analytical predictions and simulation results for time-dependent cavity radius R(t).

Main Results:

• Quantitative agreement was achieved between the modified Rayleigh-Plesset equation and molecular dynamics simulations.
• The collapse velocity is approximated by the ratio of interfacial tension to solvent viscosity (v ≈ γ/η).
• Curvature corrections were found to accelerate collapse dynamics on length scales below approximately 1 nm, relevant to hydrophobic solvation.

Conclusions:

• The study provides a validated analytical framework for describing nanoscale cavity collapse in water.
• The findings offer insights into the role of interfacial tension and viscosity in dictating collapse dynamics.
• This work serves as a foundation for developing efficient implicit models for water dynamics in nanoassembly and protein systems under non-equilibrium conditions.