Zinc Oxide Nanowire Forest for Pool Boiling Heat Transfer

Abstract

Zinc oxide (ZnO) nanowire forest is applied for the electronics cooling by means of pool boiling heat transfer. The forest was composed of lengthwise grown backbone and branched nanowires, which were highly dense and tree-like hierarchical structures. The platinum heater and resistance temperature detector were fabricated by microfabrication on one side of silicon chips and nanowire forest was synthesized on the other side. The superheat and heat flux were evaluated at steady state while the voltage in the heater was increased gradually. The heat flux gradually increased linearly with superheat at the initial stage of heating due to convective heat transfer and abruptly increased once the coolant started to boil. It seemed that the nanowire forest played a role of increased bubble nucleation sites with superhydrophilic nature leading to enhancement of boiling heat transfer. This sheds light on application of nanostructured surface as an effective electronics cooling by boiling heat transfer. (C) 2012 The Japan Society of Applied Physics