Optical control of electroosmosis

Principal Investigator: Pál Ormos
This project is part of the EU-FP6 cooperation ATOM-3D

Light is used to dynamically control the pattern of electroosmotic flow in a microfluidic channel. One wall of the channel is formed by a photoconductor film in a specific geometry. Illumination of this surface results in an increase of the conductivity that modifies the structure of the electric field inside the channel. A dramatic change of the electroosmotic flow pattern can be achieved. This approach provides useful capabilities for the manipulation of fluids in microfluidic systems like directing flow and mixing.

Click on the left image below to see a movie (avi, 2.79MB) of the experiment:



Trajectories of selected tracer particles characteristic to the flow pattern in the excited state:



Simulation (3D finite element method) of the phenomenon (fluid velocity in µm/s):



Reference:
L. Oroszi, A. Dér, H. Kirei, V. Rakovics, and P. Ormos, Manipulation of microfluidic flow pattern by optically controlled electroosmosis, Microfluidics and Nanofluidics, Accepted, Available Online (2008)