Berlin 2005 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 100: Poster Session I

AKB 100.12: Poster

Samstag, 5. März 2005, 16:45–18:45, Poster TU D

Anomalous Flow in Microfluidic Poly(dimethylsiloxane) Channels — •Thanh Tu Duong, Alexandra Ros und Dario Anselmetti — Experimental Biophysics and Applied Nanosciences, Physics Faculty, Bielefeld University

The application of microfluidic devices in various bioanalytical fields requires a detailed knowledge of material properties. Today’s microfluidic devices are fabricated using a variety of materials. Especially Poly(dimethylsiloxane) (PDMS) is the material of choice due to its low fabrication costs based on rapid prototyping. However, for microfluidic PDMS channels where one dimension is smaller than 20µ m, an anomalous flow behaviour is observed.
In a simple linear microfluidic channel sample from both reservoirs flows into the centre of the channel with a linear decreasing flow velocity. At first glance this behaviour is in contradiction to the equation of continuity, but on closer examination this phenomena is caused by the water permeability and evaporation of water through PDMS. Due to this effect the ionic strength of the buffer and hence the zeta potential changes in time. Therefore, control of the evaporation rate is crucial for future microfluidic applications based on PDMS. In this work we present a method to control and eliminate the evaporation of water through PDMS.