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Journal Articles Physics of Fluids Year : 2014

Evidence of slippage breakdown for a superhydrophobic microchannel

Abstract

A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air interfaces at the superhydrophobic surface. The simultaneous access to the meniscus and velocity profiles allows us to put under a strict test the no-shear boundary condition at the liquid-air interface. Surprisingly, our measurements show that air pockets in the surface cavities can sustain non-zero interfacial shear stresses, thereby hampering the friction reduction capabilities of the surface. The effects of the meniscus position and shape as well as of the liquid-air interfacial friction on the surface performances are separately assessed and quantified.
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Dates and versions

hal-02313467 , version 1 (04-02-2021)

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Guido Bolognesi, Cécile Cottin-Bizonne, Christophe Pirat. Evidence of slippage breakdown for a superhydrophobic microchannel. Physics of Fluids, 2014, 26 (8), pp.082004. ⟨10.1063/1.4892082⟩. ⟨hal-02313467⟩
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