Thermal rectification at water/functionalized silica interfaces

M Hu and JV Goicochea and B Michel and D Poulikakos, APPLIED PHYSICS LETTERS, 95, 151903 (2009).

DOI: 10.1063/1.3247882

Using nonequilibrium molecular dynamics simulations, we study the thermal diode effect in a system composed of silica, self-assembled monolayers (SAMs) at the silica surface and water surrounding this system, by imposing a series of positive and negative heat currents. We have found that in the limit of large heat currents, the thermal conductance at the SAMs-water interface is about 1000 MW/m(2) K at room temperature for heat flowing from the SAMs to the water and 650 MW/m(2) K for heat flowing from the water to the SAMs, respectively, resulting in a thermal rectification of up to 54%. Analysis of the radial distribution function of oxygen-oxygen atoms in water indicates that the origin of the thermal rectification resides in the strong temperature dependence of the hydrogen bonds in water. (C) 2009 American Institute of Physics. doi:10.1063/1.3247882

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