It is well known that nanoparticles deposited on a heating surface during nanofluids boiling can change the characteristics of the heating surface and increase the critical heat flux (CHF) dramatically. We considered a new approach to investigate the nanoparticle surface effect on CHF enhancement using surfaces modified with artificial micro, nano, and micro/nano structures similar to deposited nanoparticle structures through the anodic oxidation on the zirconium alloy heater. We examined the effect of the capillary wicking action ability on the CHF enhancement due to the micro, nano, and micro/nano structured surfaces. The results demonstrated that the CHF enhancement on the modified surfaces was a consequence of the capillary wicking action ability of the artificial micro/nano structures through the high-speed visualization of the capillary wicking action. (C) 2011 Elsevier Ltd. All rights reserved.