Manipulating thermal resistance at the solid-fluid interface through monolayer deposition

Area of Science:

• Materials Science
• Thermodynamics
• Computational Physics

Background:

• Heat transfer at solid-fluid interfaces is crucial for many applications.
• Interfacial thermal resistance (Kapitza resistance) governs heat flow across dissimilar materials.
• Monolayer coatings can modify interfacial properties, but their precise impact on heat transfer is not fully understood.

Purpose of the Study:

• To investigate the effect of monolayer properties on heat transfer at a solid-fluid interface.
• To quantify the influence of monolayer atomic mass and inter-particle interaction energy on Kapitza resistance.
• To elucidate the underlying mechanisms governing heat transfer modulation by monolayers.

Main Methods:

• Non-equilibrium molecular dynamics simulations were employed.
• System parameters included a solid substrate, a fluid, and a monolayer coating.
• Monolayer properties varied: atomic mass (m_M) and interaction energy (ε_MM).

Main Results:

• Interfacial thermal resistance (Kapitza resistance) is significantly affected by monolayer insertion.
• Kapitza length increases monotonically with increasing monolayer atomic mass (m_M), independent of ε_MM.
• Fluid adsorption has a secondary role compared to monolayer properties in altering Kapitza resistance.

Conclusions:

• Monolayer atomic mass is a dominant factor determining Kapitza resistance at the solid-fluid interface.
• The observed trends can be explained by analyzing phonon spectrum overlap via vibrational density of states.
• A fourth-order polynomial function describes the combined effect of m_M and ε_MM on Kapitza resistance.