Schematic representation summarizing enhancement features used in literature—increased surface area [1,2], additional nucleation sites [3,4] (reprinted with permission from Patil and Kandlikar (2014), copyright 2014 Elsevier), separate liquid–vapor pathways [5–7] (reprinted with permission from Kandlikar (2013), copyright 2013 AIP publishing LLC), wicking [8] (reprinted with permission from Rahman et al. (2014), copyright 2014 American Chemical Society), roughness [9], wettability [10], and microlayer-partitioning [11]