Regensburg 2007 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 24: Micro and Nano Fluidics II: Soft Objects in Flow + Slippage
CPP 24.6: Talk
Thursday, March 29, 2007, 11:15–11:30, H37
Ratchet driven microfluidic transport: the case of two liquid layers — •Uwe Thiele1 and Karin John2 — 1Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str. 38, 01187 Dresden, Germany — 2Laboratoire de Spectrométrie Physique, Université Joseph Fourier Grenoble I, BP 87 - 38402 St.-Martin-d'Hères Cedex, France
We extend our previously derived model for ratchet-driven microfluidic transport [1] to the case of two layers of immiscible liquids confined in a capacitor.
The transport relies on field-induced morphological changes of the free liquid-liquid interface based on a switchable, spatially asymmetric, periodic interaction of the liquid-liquid interface and the substrates. The concept is exemplified using an evolution equation for the profile of the interface between two dielectric liquid layers under an spatially inhomogeneous, time-periodic voltage. We analyse the influence of the various phases of the ratchet cycle on the transport properties.
We discuss conditions for maximal transport for the case of periodic switching between two potentials differing by translation in space by half a period. This constellation allows for the transport of droplets of liquid 1 in liquid 2.
[1] K. John and U. Thiele, http://arxiv.org/abs/physics/0611144 (2006).