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. Author manuscript; available in PMC: 2013 Jun 6.
Published in final edited form as: Adv Funct Mater. 2012 Mar 13;22(11):2223–2234. doi: 10.1002/adfm.201103017

Figure 3.

Figure 3

Engineered textured directional surfaces with asymmetric or periodic structures. (a) Micropost array for directional drop transport. Zoomed image shows details of asymmetric positioning of posts. Scale bars 200 µm (left) and 100 µm (right). Reprinted with permission of Chung et al.[32] Copyright 2010, SPIE. (b) Wax microratchet surfaces for directional drop transport. Scale bar 1 mm. Reprinted with permission from Sandre et al.,[34] copyright (1999) by the American Physical Society. (c) Milliratchet surface for directional drop transport powered by the Leidenfrost effect. Scale bar 1 mm. Source: Lagubeau et al.,[36] reprinted with permission from Macmillan Publishers: Nature Physics, copyright 2011. (d) Shaped micropillar array for directional droplet spreading. Scale bars 200 µm (left) and 50 µm (right). Source: Jokinen et al.,[37] copyright (2009) John Wiley & Sons. (e) Nanofilm with tilted nanorods acting like nanoratchets for directional drop transport and adhesion. Scale bars 5 µm (left), 1 µm (middle, right). Source: Malvadkar et al.,[39] reprinted with permission from Macmillan Publishers: Nature Materials, copyright 2010. (f) Ion track textured surface with directional contact angle hysteresis. Scale bar 50 µm. Reprinted with permission from Spohr et al.[40] Copyright (2010) American Chemical Society. (g,h) Tilted nanohairs for directional wetting and drop spreading. Scale bars (g) 1 µm and (h) 10 µm. Sources: (g) Kim and Suh[41] – reproduced by permission of The Royal Society of Chemistry. (h) Chu et al.,[42] reprinted with permission from Macmillan Publishers: Nature Materials, copyright 2010. (i) Microratchet surface for directional dry adhesion. Scale bars 500 µm (left) and 20 µm (right). Source: Parness et al.,[43] reprinted with permission of The Royal Society, copyright 2009. (j) Tilted nanorods for directional dry adhesion. Scale bar 10 µm. Reprinted with permission from Lee et al.[44] Copyright 2008, American Institute of Physics. (k) Hierarchical texture (micro/nano) for directional dry adhesion. Scale bars 10 µm (left), 1 µm (right). Source: Jeong et al.,[45] copyright (2009) National Academy of Sciences, U.S.A. (l) Microchannel with ratchet-shaped walls for directional particle transport. Scale bar 2 µm. Reprinted with permission from Kettner et al.[47] Copyright (2009) by the American Physical Society.