Quantifying heat transfer trade-offs related to fluid-solid interfaces with nanoscale texturing

Tailoring the thermal transport properties across fluid-solid interfaces has broad impacts on thermal management in a wide range of electronic and biomedical applications. In this work, we study the role that nanoscale texturing of the fluid-solid interface plays on heat transfer across a nanofluidic device. We perform molecular-dynamics (MD) simulations of a simple fluid, investigating thermal transport properties as a function of surface patterning and fluid thermodynamic conditions. We show that patterning can induce solid-like structure and dynamics in the vicinity of the fluid-solid interface, thereby shifting the vibrational modes supported by fluid in the vicinity of the interface and reducing interfacial thermal resistance. However, in contradistinction to classical fin theory, we demonstrate that nanoscale fins do not necessarily improve the overall heat transfer coefficient across a nanofluidic device employing these fins. We rationalize this observation by considering the role of surface patterning on the thermal conductivity of a thin film. We present a thermal resistance network analysis that highlights the operating conditions under which nanoscale fins can lead to improved thermal transport across a nanofluidic device.