In this study, boiling experiments were conducted with 2-propanol/water mixtures in a confined gap under various gravity levels to examine the Marangoni effects on near-bubble microscale transport. Full boiling curves were obtained and two boiling regimes determined-nucleate and pseudo film boiling. The transition condition and the critical heat flux were also identified. Relative to pool boiling, the gap geometry caused lower CHF values, and deteriorated heat transfer at high superheated temperatures. This influence was particularly significant when greater Marangoni forces were present under reduced gravity conditions. The results of this study demonstrate the complex interaction that these three factors-Marangoni force, gravity level, and gap size-have on heat transfer. (C) 2004 Elsevier Ltd. All rights reserved.