Fabrication of round channels using the surface tension of PDMS and its application to a 3D serpentine mixer

Kangsun Lee, Choong Kim, Kyeong Sik Shin, Jin Woo Lee, Byeong Kwon Ju, Tae Song Kim, Seung Ki Lee, Ji Yoon Kang

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


A novel fabrication technique was developed to fabricate round microchannels and applied to a micro mixer having a barrier structure using surface tension of PDMS. When the solidified PDMS layer (channel layer) contacts the liquid PDMS film (meniscus layer), a meniscus is formed around the sidewall in the microchannel due to surface tension. The external load pressure and contact area of the channel layer were adjusted to form various cross-sectional shapes such as a U shape, ellipse, semi-circle and circle. Since the width of the channel also determines the depth formed by the difference in capillary height, a multi-depth channel can be fabricated using a one-step process. It was applied to a dual-depth serpentine mixer, eliminating the aligned bonding of conventional soft lithography. The 3D-structure mixer enhanced mixing performance in the range of Re > 10 compared with a 2D-structure. It could fully mix phenolphthalein and sodium hydroxide when the Reynolds number was 80. The suggested fabrication method could be very useful in various microfluidic devices that need round corners and multi-depth channels.

Original languageEnglish
Article number016
Pages (from-to)1533-1541
Number of pages9
JournalJournal of Micromechanics and Microengineering
Issue number8
Publication statusPublished - 2007 Aug 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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