A molecular dynamics simulation on the relationship between contact angle and solid-liquid interfacial thermal resistance

Abstract

With the fast development of nanotechnology, the solid-liquid interfacial thermal resistance draws increasing research interest due to its importance in nanoscale energy transport. The contact angle is an important quantity characterizing the interfacial properties and is easy to be measured experimentally. Previous researchers have tried to correlate the contact angle to the interfacial thermal resistance. Using molecular dynamics simulation, we have calculated the contact angle and interfacial thermal resistance at a solid/liquid interface and discuss the relationship between the two quantities. The solid/liquid bonding strength and the solid properties are varied to test their effects on both contact angle and interfacial thermal resistance. The simulation results demonstrate that with increasing solid/liquid bonding strength, both the contact angle and interfacial thermal resistance decrease. However, the bonding strength between solid atoms and the solid atomic mass influence the interfacial resistance remarkably while they have little effect on the contact angle. It is because the variations of the solid atomic mass and the bonding strength between solid atoms change the frequency distribution of the vibration of the solid atoms, resulting in a difference in the thermal vibrational coupling between solid and liquid atoms. Our study indicates that the interfacial thermal resistance is not only related to the interfacial solid-liquid bonding strength which is characterized by the contact angle, but also the thermal vibrational coupling between solid and liquid atoms. There is not a simple relationship between the contact angle and the interfacial thermal resistance. The contact angle could not be used as an exclusive criterion for solid-liquid interfacial resistance estimation.