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

Heat transfer across an interface between a monolayer coated solid substrate and fluid has been extensively analyzed through a series of non-equilibrium molecular dynamics simulations. The effect of the monolayer was studied by varying its atomic mass (m(M)) and interaction energy between monolayer particles (ε(MM)). Even though the fluid adsorption plays a role in heat transfer at the solid–fluid interface, we found that the interfacial thermal resistance (Kapitza resistance) is highly affected by the insertion of monolayer without any further change in the liquid structure near the solid surface. The Kapitza length monotonically increases with the increase of m(M) irrespective of ε(MM). The observations were explained by analysis of the overlap of the phonon spectrum at the interface using vibrational density of states. The effect of the monolayer on the Kapitza length was summarized by a fourth polynomial function that demonstrates the contribution of both m(M) and ε(MM) with respect to each other on the Kapitza resistance within the parametric range studied.