Figure 2
Arraying and shape-control of microsphere-tipped PDMS micropillars. (a) Three PDMS micropillars closely packed while exhibiting highly different structural characteristics. The heights are (from left to right) 454, 900 and 1570 µm, respectively. With the corresponding average diameters at 23.5, 27.0, and 28.4 μm, the aspect ratios are 19.3, 32.6 and 54.6. The micropillars are separated by ~900 µm. (Scale bar: 200 µm). (b) The tapering indices (TI) of PDMS micropillars drawn with three different levels of UV curing light intensity during the drawing process (Fig. 1d). The error bars represent the standard deviation from 3~5 samples. (c) The optical micrograph of a PDMS micropillar with the in situ UV curing light OFF. The tapering index is 1.0%. (Scale bar: 100 μm). (d) The optical micrograph of a PDMS micropillar drawn with the in situ UV curing light ON. The tapering index is 3.7%. (Scale bar: 100 μm).
