2. Vortex Fluidic Technology
From manipulating single-cell organisms to processing advanced materials and small molecule synthesis, these processing capabilities and many more can be conducted through a VFD by accurately regulating the shear force experienced by the fluid, among various other parameters that affect the fluid dynamics. As shown in Figure 1, the VFD has noticeably unique features and capabilities. Typically a VFD has a glass or quartz tube with an external diameter of either 10 mm, 15 mm, or 20 mm, and can be spun at speeds from 1000 to 10000 rpm while inclined at an angle θ which can be varied from 90° to 0° with recent developments towards -45° processing17. The inclination angle and rotational speed control the management of shear rates at high magnitudes, with the fluid dynamics being inherently complex when θ >> 0°18. The formation of a thin film from the liquid in the VFD witnesses high shear from the interaction between gravitational and centrifugal forces. These forces are accompanied by the appearance of Stewartson/Ekman layers as fluid flows upwards on the rotating tube’s internal surface and downwards near the liquid’s surface, parallel to the rotational axis of the rotating tube.