Superhydrophobic, passive microvalves with controllable opening threshold: exploiting plasma nanotextured microfluidics for a programmable flow switchboard


Plasma processing is used to create passive superhydrophobic on–off valves with tailored opening pressure inside microfluidic devices. First, anisotropic O2 plasma etching on polymeric microchannels is utilized to controllably roughen (nanotexture) the bottom of the microchannel. Second, the nanotextured surfaces are hydrophobized by means of a C4F8 plasma deposition step through a stencil mask creating superhydrophobic stripes or patches. The superhydrophobic patches play the role of on/off valves with predesigned opening pressure threshold (in the range 40–110 mbar), determined by the microchannel dimensions and the size of the nanotexture on the patch. These valves are integrated inside microchannel networks paving the way to autonomous microfluidic devices. To this aim, we present a novel preprogrammable flow switchboard that can split and control the liquid flow for multiple analysis purposes. The proposed valves present an example of how effectively plasma nanoscience and nanotechnology can be applied to microfluidics/nanofluidics and analytical chemistry.

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Authors kindly acknowledge Associate Professor Grigoris Kaltsas from TEI of Athens, Department of Electronics, for his help in the pressure measurements by providing access to the setup shown in Fig. 1. This work was cofinanced by Hellenic Funds and by the European Regional Development Fund (ERDF) under the Hellenic National Strategic Reference Framework (NSRF) 2007–2013, of the Project “THALIS-DESIgn and fabrication of Robust supErhydrophobic/philic surfaces and their application in the realization of ‘smart’ microfluidic valves” (

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Correspondence to Evangelos Gogolides.

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Ellinas, K., Tserepi, A. & Gogolides, E. Superhydrophobic, passive microvalves with controllable opening threshold: exploiting plasma nanotextured microfluidics for a programmable flow switchboard. Microfluid Nanofluid 17, 489–498 (2014) doi:10.1007/s10404-014-1335-9

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  • Superhydrophobic microfluidics
  • Plasma nanotextured microfluidics
  • Passive valving