Cross-plane thermal conductivity of thin films characterized by Flash DSC measurement

Abstract

We employed Flash DSC measurements on the melting point difference between two indium particles separately placed on the top of polyethylene thin films and on the empty reference cell. We found that the melting point differences exhibit a linear dependence on the heating rates, evidencing Fourier’s heat conduction law along the cross-plane (or thickness) direction of thin films at the temperatures around the indium melting point. We derived the equation to characterize the cross-plane thermal conductivity of thin films, which combines the linear slope with the intrinsic material properties such as density, specific heat capacity and film thickness. In principle, the valid temperature range is subject to change with standard materials different from indium particles. Our approach appears as an indirect yet simple and fast method to characterize the cross-plane thermal conductivity of thin films (or more general, 2D matter) of variable materials (different states, compositions or constructions), with film thickness and sample mass down to nanoscales, promising for broad application.