Enhanced effect of solid-liquid interface thermal rectification by surfactant: A molecular dynamics study

Thermal rectification effect enables adjustment of the system's thermal transport properties in response to the direction of the temperature bias, thereby assuming a pivotal function in the domain of thermal control technology. Employing molecular dynamics simulations, the solid-liquid thermal rectification is studied by introducing surfactants into the liquid. The thermal rectification ratio of the system can be significantly enhanced by adding surfactants. The underlying mechanism of the thermal rectification is analyzed by calculating the interfacial thermal resistance distribution, temperature profile, and liquid and surfactant density distribution. Such a high thermal rectification factor is primarily due to the different surfactant-adsorption behavior when reversing the temperature bias. Adding surfactants to the liquid enhances forward heat transfer while reverse heat transfer can be suppressed. In addition, the effect of surfactant concentration on the thermal rectification effect is also examined. The results show that the thermal rectification factor can be increased by increasing surfactant concentrations at higher temperature bias. The results of this paper present an innovative approach to improve the efficiency of thermal rectifiers.