Fig. 1: Mechanism and explanation of drop-impact printing technique.
From: Drop impact printing
a Schematic illustration showing the drop-impact setup, a droplet (diameter Do, velocity Uo) impacting on a superhydrophobic sieve (pore opening, L) to eject out a single smaller droplet (diameter Dp). The impacting drop gives rise to two modes of single-droplet ejection. b Impact cavity (IC) and (c) recoil cavity (RC). Scale bar: 200 µm. The time-lapsed images and schematic illustration for IC and RC modes show the mechanism of cavity formation and collapse using sieve #0.0045 with 65% glycerol water droplet and sieve #0.009 with pure water droplet, respectively. The drop-impact printing technique was explored in terms of the smallest ejected droplet that can be generated. d Shows a plot between water droplet diameter versus pore opening, and the insets show the corresponding patterned droplet (scale bar: 100 µm). Superhydrophobic sieves with different pore openings were used starting from sieve type #0.012 (pore opening L: 533.4 µm, wire diameter W: 304.8 µm) to #0.0020 (pore opening L: 76.2 µm, wire diameter W: 50.8 µm) and electroplated mesh (pore opening L: 25.2 µm, wire diameter W: 101.2 µm) marked in blue-dotted circle. e Scanning electron microscopy (SEM) images of sieves #0.009 and #0.0020 (scale bar: 100 µm, magnified image scale bar: 2 µm).
