Controlling capillary-driven surface flow on a paper-based microfluidic channel

Joel Songok, Martti Toivakka

Research output: Contribution to journalArticleScientificpeer-review

54 Citations (Scopus)


This paper describes two methods for controlling capillary-driven liquid flow on microfluidic channels. Unlike flow driven by external forces, capillary-driven flow is dominated by interfacial phenomena and, therefore, is sensitive to the channel geometry and chemical composition (surface energy) along the channel. The first method to control fluid flow is based on altering surface energy along the channel through regulation of UV irradiation time, which enables adjusting the contact angle along the fluid path. The slowing down (delay) of the liquid flow depends on the stripe length and its position in the channel. Using this technique, we generated flow delays spanning from a second to over 3 min. In the second approach, we manipulated the flow velocity by introducing contractions and expansions in the channel. The methods used herein are inexpensive and can be incorporated to the microfluidic channel fabrication step. They are capable of controlling liquid flow with precise time delays without introducing the foreign matter in the fluidic device.
Original languageUndefined/Unknown
Pages (from-to)1–9
JournalMicrofluidics and Nanofluidics
Issue number63
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed


  • paper-based microfluidics
  • microfluidics
  • Capillary Surface Flow
  • capillary flow

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