Figure 3
Shape-engineering of PDMS micro-tentacles.
(a) A schematic diagram of a humped PDMS micro-tentacle and the change in its I due to the hump. Calculated loci (b) and y-values (c) of three microtubes with different hump configurations. Plain: no axial change in cross-sectional shape, Hump A: with a properly positioned hump (Ls = 0.21·L) and Hump B: with an improperly positioned hump (Ls = 0.55·L). Hump A re-entered the first quadrant with y > 0, achieving an inward spiraling. Hump B, on the other hand, actually rendered the bending worse than that of the non-humped Plain. (d) Overlapped images of microtube actuations before (P) and after (B) installing an improperly positioned hump (arrow-marked). The RoC got bigger even with the hump. (e) Micrograph of a micro-tentacle with a hump (arrow-marked) capable of achieving a 2-turn spiraling with the final RoC of 210 μm. (Scale bars: 1 mm).
