Fig. 4

a Formation of nanowires at solution boundary, b entrapment of nanowires through activation of donut-shaped clamp, c close-up of trapped nanowire under donut clamp, d nanowires stay in position after careful deactivation of clamp under non-flowing conditions, e highlighting different sizes of nanowire bundles achievable by use of various clamp shapes. Scale bars a, b, e 100 μm and c, d 50 μm. Reprinted with permission from Ref. [15]. Copyright 2011 The Royal Society of Chemistry