CAPILLARITY-RESTRICTED MODIFICATION METHOD FOR GAS/LIQUID SEPARATION AND GAS BUBBLE PURGE IN MICROCHANNELS

摘要

A surface modification control method for microchannels was developed for gas-liquid microchemical operations in microchips. In this method, shallow and deep microchannels were modified with hydrophobic and hydrophilic groups, respectively. This patterning was prepared based on principle of capillarity. Validity of the patterning was confirmed by measuring aqueous flow leak pressure from the hydrophilic microchannel to the hydrophobic one. The leak pressure agreed well with theoretical prediction from Young-Laplace equation. In order to demonstrate usefulness and effectiveness of the method, air bubble was introduced to the hydrophilic microchannel and purged from the hydrophobic-hydrophilic patterned microchannels. Next, the patterning structure was applied to remove dissolved oxygen by contacting the aqueous flow with nitrogen-flow. The concentration of dissolved oxygen decreased with contact time and its time course agreed well with numerical simulation. These demonstrations showed that the proposed patterning method is promising to general microfluidic gas-liquid operations.