Fig. 2: Droplet generation at different pressures of the oil and water phases.

Water droplet generation at a constant water pressure of 11.9 mbar and different oil pressures: 30.3, 29.7, 15.7 and 9.7 mbar in a–d, respectively, for the microchannel with a channel height h = 75 µm, channel width w_o = 150 µm, w_w = 75 µm, and w_out = 75 µm, and channel length l_o = 10 mm, l_w = 10 mm and l_out = 1.5 mm for the water inlet, oil inlet, and outlet channels, respectively. The water enters the T-junction from the water channel on the left and is cut off into droplets by the oil flow from the top channel. Supplementary Videos 1-4 illustrate the four different formation regimes depicted in a–d. The mineral oil phase consists of 2 wt.% Span 80. e Pressure phase map for dispersed droplet generation. Droplets can be generated within the green region. Yellow and blue regions are for the conditions where oil pressure is higher than the upper threshold and lower than the lower threshold, respectively