Bubble Removal in Microfluidic Devices Using Nanofibrous Membranes

This paper presents an experimental study to determine bubble removal characteristics of nanofibrous membranes in microfluidic devices. It is well known that the presence of gas bubbles in fluidic channels can cause significant flow disturbances and adversely affect the overall performance and operation of microfluidic devices. In this study, a microfluidic device is designed and fabricated to generate and extract bubbles from a microfluidic channel. A T-junction is used to produce controllable bubbles at the entrance of fluidic channel. The generated bubbles are then transported to a bubble removal region and vented through a highly porous hydrophobic membrane. Four different hydrophobic PTFE membranes with different pore sizes ranging from 0.45 to 3 μm were used to permeate air bubbles. The fluidic channel width was 500 μm and channel height ranged from 100 to 300 μm. The effects of pore size, channel height, and liquid flow rate on the bubble removal rate are investigated. The results reveal that the rate of bubble removal increases with increasing the pore size and channel height but decreases with increasing the liquid flow rate.