Rational Micro-Nano Structuring for Thin Film Evaporation

Heat management in electronics and photonics devices is a critical challenge that impedes the accelerated breakthrough in these fields. Among approaches for heat dissipation, thin film evaporation with micro/nano structures has been one of the most promising approaches that can address future technological demand. The geometry and dimension of these micro/nano structures directly govern the interfacial heat flux. Here, through theoretical and experimental analysis, we find that there is an optimal dimension of micro/nano structures that maximizes the interfacial heat flux by thin film evaporation. This optimal criterion is a consequence of two opposing phenomena: non-uniform evaporation flux across a liquid meniscus (divergent mass flux near three phase contact line) and the total liquid area exposed for evaporation. This general criterion is independent of the solid material and thermo-physical properties of the cooling liquid. This study paves the path for development of high-performance thermal management systems.