• Ingeniatrics has also a great number of patents related with size-controlled microbubble production. Our microfluidic technologies allow the generation of perfectly monodisperse microbubbles and microfoams from a few microns to several hundreds of microns, by means of simple and robust geometries based on the Flow Focusing phenomenon (both planar 2D and axisymmetric 3D configurations). The bubbles are produced by a self-excited breakup of a short gas microligament coflowing in a focused liquid stream (see Figure 1).

Figure 1: Cusplike bubble, attached to a capillary gas-feeding tube, from whose cusp a gas ligament issues through the orifice placed in front of the capillary.

• The produced microbubbles can be discharged through a drilled thin plate, allowing the generation of bubble injection, foams of gas microcapsules (see Figure 2). When bubbles are discharged within the same liquid (Figure 2.a), they rise and settle, forming in many cases a “mesocrystal foam” or lattice (Figure 2.d). Such bubbles are virtually equal in size.

Figure 2: The liquid used to focus the gas is expelled into the same liquid (a). The liquid with the bubbles is expelled into air, and a gas filled liquid jet with the diameter of the orifice is produced (b). This liquid jet eventually breaks up into equal-size gas filled microcapsules (c). Bubbles created in case (a) can rise and settle into a monodisperse microfoam (d), here 75µm

Alternatively, the generated microbubbles can be collected and discharged through a capillary tubing, resulting in the generation of a perfectly monodisperse microfoam (see Figure 3).

Figure 3: (a) Direct production of monosized wet microfoam using flow focusing and a capillary collector. (b) A sample of the monodisperse foam produced (diameter = 30µm). In the circular insert, a wire with 50µm in diameter for size reference.

Such geometries can be easily implemented and multiplexed in small or miniature devices. The potential applications of these microfluidic devices include biomedicine (i.e. ultrasound contrast agents), food industry, aerospace engineering, house ware, etc. Contact us for more information.