Contact angle dependence on the fluid-wall dispersive energy

Area of Science:

• Physics
• Physical Chemistry
• Materials Science

Background:

• Understanding liquid behavior at interfaces is crucial for various scientific and engineering applications.
• The Lennard-Jones fluid model is a standard for studying fluid properties.
• Contact angle phenomena are influenced by fluid-fluid and fluid-wall interactions.

Purpose of the Study:

• To investigate the influence of fluid-wall dispersive interaction energy on the contact angle of a Lennard-Jones fluid confined between parallel walls.
• To explore the effect of temperature on the meniscus behavior.
• To provide a basis for adjusting fluid-wall interaction potentials for contact angle measurements.

Main Methods:

• Molecular dynamics simulations were employed to study the menisci of a truncated and shifted Lennard-Jones fluid.
• The characteristic energy of the unlike dispersive interaction between fluid molecules and wall atoms was systematically varied.
• Temperature was varied across a significant range, from the triple-point to the critical temperature of the bulk fluid.

Main Results:

• A clear transition between obtuse and acute contact angles was observed.
• This transition was found to occur at a specific, temperature-independent magnitude of the fluid-wall dispersive interaction energy.
• The study systematically mapped the influence of interaction energy and temperature on contact angles.

Conclusions:

• The contact angle of confined Lennard-Jones fluids is primarily determined by the fluid-wall dispersive interaction energy.
• The observed transition point is a robust characteristic, independent of temperature within the studied range.
• Simulation results can guide the development of accurate fluid-wall interaction models for predicting contact angles.