열모세관에 의한 미소액적 구동과 모세관 밸브

Micro droplet driven by thermocapillary and capillary valve

  • 임남혁 (서울대학교 기계항공공학부 대학원) ;
  • 김성욱 (서울대학교 마이크로열시스템연구센터) ;
  • 유정열 (서울대학교 기계항공공학부)
  • 발행 : 2003.04.23

초록

This paper presents the design, fabrication, and testing of the capillary-induced pressure drop valve, thermocapillary pumping of liquid droplet in hydrophilic channels and the splitting of droplet. The capillaryinduced pressure drop is derived with thermodynamic approach considering three-dimensional meniscus shape which is essential for calculating pressure drop in the diverging shape channel when the aspect ratio is close to one. The micro channel is fabricated via MEMS processes, which consists of the liquid stop valve to retard the liquid droplet, thermocapillary pumping region and the bifurcation region. Also the micro heaters are fabricated to drive the droplet by thermocapillary. The theoretical approaches agree well with the experimental data. The functionality of capillary valve is confirmed to be valid when the aspect ratio is smaller than one. To overcome the difficulty in splitting of the droplet due to the pressure drop in the general Y-shape channel, the protrusion shape is employed for easy splitting in the bifurcation channel.

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