title: Principles of transverse flow fractionation of microparticles in superhydrophobic channels.
abstract: We propose a concept of fractionation of micron-sized particles in a microfluidic device with a bottom wall decorated by superhydrophobic stripes. The stripes are oriented at an angle α to the direction of a driving force, G, which generally includes an applied pressure gradient and gravity. Separation relies on the initial sedimentation of particles under gravity in the main forward flow, and their subsequent lateral deflection near a superhydrophobic wall due to generation of a secondary flow transverse to G. We provide some theoretical arguments allowing us to quantify the transverse displacement of particles in the microfluidic channel, and confirm the validity of theoretical predictions in test experiments with monodisperse fractions of microparticles. Our results can guide the design of superhydrophobic microfluidic devices for efficient sorting of microparticles with a relatively small difference in size and density.
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119071 Moscow, Russia. oivinograd@yahoo.com.
authors.forename: Evgeny S
authors.initials: ES
authors.lastname: Asmolov
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Dubov
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Nizkaya
authors.forename: Alexander J C
authors.initials: AJ
authors.lastname: Kuehne
authors.forename: Olga I
authors.initials: OI
authors.lastname: Vinogradova
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D008962:Models, Theoretical; D010316:Particle Size; D011312:Pressure