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Dynamics of capillary drying in water.
Kevin Leung1, Alenka Luzar, Dusan Bratko
1Sandia National Laboratories, MS 1421, Albuquerque, New Mexico 87185, USA.
Physical Review Letters
|March 14, 2003
Summary
Water readily evaporates from thin hydrocarbon films at ambient conditions. Thicker films remain liquid, and dissolved gases do not significantly hinder evaporation, according to atomistic simulations.
Area of Science:
- Physical Chemistry
- Materials Science
Background:
- Understanding water evaporation from confined geometries is crucial for various applications.
- Hydrocarbon-water interfaces present unique challenges due to differing molecular properties.
Purpose of the Study:
- To determine the kinetic viability of capillary evaporation for water confined in hydrocarbon-like slits.
- To quantify evaporation rates and activation barriers using atomistic simulations.
Main Methods:
- Atomistic simulations were employed.
- Open ensemble Monte Carlo-umbrella sampling and molecular dynamics simulations were utilized to estimate activation barriers and evaporation rates.
Main Results:
- At ambient conditions, water readily evaporates from films approximately four molecular diameters thick, with rates on the order of 10^5 (nm^2 s)^-1.
- Water films thicker than a few nanometers persist in a metastable liquid state.
- Dissolved atmospheric gas molecules did not significantly reduce the activation barrier for evaporation.
Conclusions:
- Capillary evaporation of water in thin hydrocarbon-like films is kinetically viable under ambient conditions.
- Film thickness is a critical factor determining the persistence of liquid water.
- The presence of dissolved gases has a negligible impact on the evaporation kinetics of confined water.