Surface-Heating Algorithm for Water at Nanoscale.

Area of Science:

• Computational physics
• Materials science
• Physical chemistry

Background:

• Molecular dynamics (MD) simulations are crucial for understanding nanoscale phenomena.
• Simulating transient surface heating and water evaporation in MD has been a significant challenge.
• Existing models often lack the ability to accurately capture differential thermal gradients during surface heating.

Purpose of the Study:

• To develop and validate a novel surface-heating algorithm for molecular dynamics simulations of water.
• To investigate the evaporation dynamics of water droplets on a platinum surface under varying temperatures.
• To analyze the resulting contact angles, evaporation profiles, and temperature gradients within the droplet.

Main Methods:

• Development of a new surface-heating algorithm for MD simulations.
• Application of the algorithm to simulate water droplet evaporation on a platinum substrate.
• Comparison of simulation results (contact angles, evaporation profiles) with theoretical, numerical, and experimental data.
• Analysis of the temperature gradient within the water droplet.

Main Results:

• The algorithm successfully simulates the transient evaporation of water heated from a surface.
• Calculated contact angles align well with existing theoretical, numerical, and experimental findings.
• The study elucidated the evaporation profile along the droplet's radius and height.
• A realistic differential thermal gradient within the water was observed, consistent with Kelvin-Clapeyron theory.

Conclusions:

• The novel surface-heating algorithm provides a validated and accurate method for simulating water evaporation in MD.
• The algorithm effectively captures transient behaviors and thermal gradients, offering new insights into surface-heating phenomena.
• This approach is highly promising for diverse applications, including thin film evaporation and the Leidenfrost effect.
• The algorithm's simplicity facilitates integration into existing simulation software and extension to various surfaces.