Increasingly smaller electronics requires improvement in performance of cooling systems to keep it operating reliably. We present herein a novel experimental study of convective heat transfer in serpentine microchannels with segmented liquid-liquid emulsions. It is demonstrated that this concept yields significant Nusselt number enhancement in microchannel heat sinks compared to that obtained using single phase liquid cooling. Laser Induced Fluorescence (LIF) is employed to measure temperature of the coolant with and without droplets, and micro-Ply is used to determine velocity field. For the segmented flow, up to four-fold increase of the Nusselt number was observed compared to pure water flow. (C) 2010 Elsevier Ltd. All rights reserved.