Importance of viscoelastic and interface bonding effects in the thermal boundary conductance of solid–water interfaces

• Analytical model for the thermal conductance at solid/liquid interfaces.
• Predictions of the conductance of selfassembled monolayers in contact with liquid water.
• Reasonable agreement with simulations and thermoreflectance data.

We propose a simple analytical treatment of the thermal boundary conductance of solid/water interfaces, using a generalization of the acoustic mismatch model. The model accounts for van der Waals interactions between water and the solid, and the high frequency dynamics, which is peculiar to liquid water. Of particular interest are the viscoelastic effects that emerge at Thz frequencies, and which allow transverse acoustic waves to propagate in liquid water. The parameters of the model may be found in handbooks, and as such is free from any fitting parameters. Comparison with molecular dynamics data shows that interfacial energy transfer is inelastic, and energy is transmitted up to the solid Debye frequency. Comparison with experimental data regarding metal/SAM (self-assembled monolayer)/water allows to estimate the different contributions to heat dissipation, and we found that interfacial heat transfer in this situation is limited by the SAM head/water conductance, the latter being well described by the viscoelastic model. We also discuss the dependence of the conductance on the adhesion energy between the solid and water.