A microfluidic route to small CO2 microbubbles with narrow size distribution

We report a new microfluidic strategy for the generation of small (<10 mu m) microbubbles with a narrow size distribution. Our approach has the following features: (i) the generation of bubbles from gaseous CO2 and (ii) the controllable dissolution of these bubbles until they reach a desired size. We examine the role of various factors on the formation and the extent of bubble dissolution and show that the final dimensions of bubbles are determined by the flow rate of the continuous aqueous phase and the acid-base equilibria established within the microchannels.