A unique solution for preventing clogging of flow channels by gas bubbles

A novel solution is presented that deals with the well known problem of clogging in microfluidic channels caused by gas bubbles. The presented approach involves the use of a single channel with different, parallel cross sections. In each of these cross-sections different capillary forces act on the fluid and on potentially present bubbles. The latter are drawn into one of the cross sections, depending on their geometry and wetting behaviour, allowing a bypass, i.e. an ongoing, increased flow in the remaining available cross sections. The resulting drag on the bubble, caused by this flow, increases its mobility. In our experiments, for low pressure differences, the flow is increased by a factor of 4 and the mobility of the gas bubbles was increased by a factor of approximately 6 as compared to a conventional channel. This method greatly reduces the system susceptibility to clogging.