Production of monodispersed micron-sized bubbles at high rates in a microfluidic device

A polydimethylsiloxane microchip consisting of a T-junction microchannel network and a thin glass capillary has been developed for the generation of microbubbles. The glass capillary is used to produce an ultrathin gas jet and to controllably block the straight liquid channel, thereby increasing the local liquid velocity near the intersection. Liquid flow rate, liquid viscosity, gas pressure, and inner diameter of the gas jet are varied to investigate the effect on bubble generation. Bubbles with a diameter down to 4.5 µm can be produced at a high rate of 7.5 kHz using a capillary with an inner diameter of 2 µm.