Figure 1.
Schematic contrasting splitting a drop by pulling each end with the method of cutting with a superhydrophobic knife.
Both drops lie on superhydrophobic surfaces. A simple rectangle can estimate the shape and contour of the drop (htop for the top contour of the stretched drop, and ho for the bottom contour of the stretched drop). The split drop results in two equally sized spheres, both of radius rd (equal to the radius of the wire loops used to pin and stretch the original droplet).
Figure 2.
Images from video footage of drop cutting experiments using a superhydrophobic knife on superhydrophobic surfaces: (A) 15 µL water drop on a Teflon glass surface separated 3 mm by wire loops is not cut into two drops and bounces back after the zinc superhydrophobic knife is elevated, (B) 50 µL drop separated by wire loops by 8 mm does cut into two drops.
Scale bar is 1 mm in both images.
Figure 3.
Images (A-D) show a curve drawn using Equation (5) superimposed on top of an example still from a video.
The curves and droplet profiles correspond closely. All scale bars are 1 mm. (A) A droplet with a volume (Vs) of 60 µL and with separation distance (ho) of 8.5 mm. The normalized time parameter, B, from Equation (5) is set to 0.70 for this curve. The parameters A and C from Equation (5) are both set to 1 in all images for simplicity. (B) Vs = 60 µL, ho = 10.5 mm, and B = 0.75 (C) Vs = 60 µL, ho = 10.0 mm, and B = 0.30 (D) Vs = 60 µL, ho = 10.0 mm, and B = 0.40. Images (C) and (D) are of the same droplet.
Table 1.
Upper Limit Predictions and Results.