Abstract
Sealed nanofluidic channels with cross-sections as small as 60 nm × 60 nm were created in polymer bilayers using the focused X-rays of a scanning transmission X-ray microscope. These structures were then characterized by near-edge X-ray absorption fine structure spectromicroscopy, atomic force microscopy and scanning electron microscopy. The cross-sectional area of the nanochannels could be tuned by adjusting the area patterned in x and y and/or manipulating the bottom layer thickness. The maximum length was found to be limited by the efficiency of excavation of patterned material out of the channel, and the stability of the polymer overlayer which seals the channel. Schemes toward interfacing these nanochannels with conventional microfluidics are discussed.
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Acknowledgments
This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation and the Canada Research Chair program. We thank Dongqing Li and Jose Moran-Mirabal for useful discussion on interfacing microfluidics with nanofluidics, Yujie Zhu for performing initial interfacing experiments, and Ash Parameswaran for providing the poly(dimethylglutarimide). We also thank David Kilcoyne and Tolek Tyliszczak for their support of the STXM facilities. The experiments were performed at beamline 5.3.2.2 of the ALS, LBNL. The ALS is supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the USA Department of Energy, under Contract No. DE-AC03-76SF00098. A.F.G.L. acknowledges support from an ALS doctoral fellowship in residence.
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Leontowich, A.F.G., Hitchcock, A.P. Fabrication of sealed nanofluidic channels using site-selective direct write (maskless) X-ray lithography. Microfluid Nanofluid 15, 509–518 (2013). https://doi.org/10.1007/s10404-013-1170-4
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DOI: https://doi.org/10.1007/s10404-013-1170-4