Microfluidic bubble-based gas sensor

This paper reports a new class of a gas sensor that utilizes the variation in bubble sizes when different gases are introduced into a liquid flow to identify gas types. The fabricated device enabled the detection of pentane (3μL) by producing the average bubble size of 130μm3, which showed size reduction by 2.4μm (1.7%) from the background bubble sizes (132.4μm) of nitrogen. The measurement also showed a preliminary correlation between the injection volume and the bubble size: increase in the injection volume of pentane from 3μL to 5μL (66.7% increases) resulted in the bubble size reduction from 1.7% to 2.1% (24% decreases) and the time span increase from 5s to 10s (100% increases).