Quantifying interfacial thermal conductance at solid-liquid interfaces using frequency-domain thermoreflectance and analytical methods

Optical methods such as time-domain thermoreflectance (TDTR) and frequency-domain thermoreflectance (FDTR) are non-contact techniques best suited to quantify thermal properties of fragile materials and interfaces which are often inaccessible to conventional probing methods. More recently, pump-probe technique has been demonstrated to measure thermal conductivity of water and thermal boundary conductance (TBC) at solid-liquid interfaces. To better understand interfacial heat transfer mechanisms in micro- and opto-electronic integrated cooling with liquids, we use the FDTR technique based on the same bidirectional heat transfer theory as the pump-probe technique. In this work we use a single bond hydrocarbon nonane to represent more complex engineered fluids to quantify TBC at solid-liquid interfaces in oil immersion or submersion cooling. In this paper we measured the TBC at nonane-Au interface to be 0.61 MW m ^-2 K and observed the measured TBC to be a factor of 10 smaller than the TBC at water-Au interface with a comparable advancing contact angle. Analytical predictions over a range of contact angles are also presented using a modified acoustic mismatch model (AMM) for solid-liquid interfaces.