Issue 21, 2013

Particle alignment in a viscoelastic liquid flowing in a square-shaped microchannel

Abstract

We demonstrate the possibility to achieve 3D particle focusing in a straight microchannel with a square cross-section by exploiting purely viscoelastic effects. Experiments are carried out by considering an elastic, constant-viscosity aqueous solution of PVP (polyvinylpyrrolidone) as the suspending liquid. Several flow rates and two channel dimensions (with a fixed particle size to channel dimension ratio) are investigated. A novel technique combining particle tracking measurements and numerical simulations is used to reconstruct the position of the flowing particles over the channel cross-section. The results show that, for all the investigated experimental conditions, particles migrate towards the channel centerline. Flow-focusing is enhanced by higher flow rates. The measured particle fractions can be rescaled according to a single dimensionless parameter, as already reported in the literature for the case of cylindrical channels. The so-obtained master curve can be used as a guide to predict the required focusing length. The effect of the entrance on the focusing channel length is also addressed. Finally, analogies and discrepancies with similar previous works are discussed.

Graphical abstract: Particle alignment in a viscoelastic liquid flowing in a square-shaped microchannel

Article information

Article type
Paper
Submitted
04 Jun 2013
Accepted
02 Aug 2013
First published
05 Aug 2013

Lab Chip, 2013,13, 4263-4271

Particle alignment in a viscoelastic liquid flowing in a square-shaped microchannel

F. Del Giudice, G. Romeo, G. D'Avino, F. Greco, P. A. Netti and P. L. Maffettone, Lab Chip, 2013, 13, 4263 DOI: 10.1039/C3LC50679G

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