Application of nanostructure on bubble trapping and degassing

This paper introduces a passive degassing mechanism by using nanostructures for bubble trapping and transporting, then by using hydrophobic porous membranes for venting bubbles in a liquid system. The bubble trapping ability is achieved by creating nanostructures to promote bubble nucleation and aggregation on the sidewalls of KOH-etched concave pits in a silicon substrate. The substrate, which is then bonded with a porous membrane, is placed in a liquid system with chemically-generated CO₂ bubbles to examine the degassing ability. The results validate that the bubbles can be easily trapped on the surfaces with nanostructures, and then vented through the porous membrane. Our proposed approach possesses the advantage of simple fabrication, great structure robustness, and rapid degassing ability, which shows its great potential as an effective means to remove the gas byproducts for cell culture and fuel cell applications.