Surface modification method of microchannels for gas-liquid two-phase flow in microchips

Akihide Hibara, Shinobu Iwayama, Shinya Matsuoka, Masaharu Ueno, Yoshikuni Kikutani, Manabu Tokeshi, Takehiko Kitamori

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151 Citations (Scopus)


A capillarity restricted modification method for microchannel surfaces was developed for gas-liquid microchemical operations in microchips. In this method, a microstructure combining shallow and deep microchannels and the principle of capillarity were utilized for chemical modification of a restricted area of a microchannel. A hydrophobic-hydrophilic patterning in microchannels was prepared as an example for guiding gas and liquid flows along the respective microchannels. Validity of the patterning was confirmed by measuring aqueous flow leak pressure from the hydrophilic microchannel to the hydrophobic one. The leak pressure of 7.7-1.1 kPa agreed well with that predicted theoretically from the Young-Laplace equation for the microchannel depth of 8.6-39 μm. In an experiment to demonstrate usefulness and effectiveness of the method, an air bubble was first introduced into 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 a 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 can be used in general microfluidic gas-liquid operations.

Original languageEnglish
Pages (from-to)943-947
Number of pages5
JournalAnalytical Chemistry
Issue number3
Publication statusPublished - 2005 Feb 1
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


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