The aim of this very new project is to extend the use of microfluidic devices into complex fluids systems in order to engineer novel self-assembled structures in a controlled way. As the mixing of different fluids is a key parameter on the self-assembly of kinetic dependent aggregates, microfluidics is a unique tool to understand and control such processes. Our research is focused on the manipulation of mixing processes where “out of equilibrium” self-assemblies result. In particular we are interested on the manipulation of simple and multiple emulsions, on the study of vesicle formation in block copolymer systems, and the study of charged polymer-ionic surfactant complex formation.
To achieve this project we are engineering different mixing devices on microchannels. These devices are based on the rotation of bipolar micron size objects (micro-stirrers) which are placed in an in-plane rotating electric field. The rotating field is obtained by means of 6 sequenced electrodes etched in one of the surfaces of the channels. The micro-stirrers are obtained by photo-polymerizing reactive nematic liquid crystal droplets, thus the liquid crystalline orientational order is “locked in” (collaboration with Brown University).

If before polymerization the liquid crystal droplets are subjected to a mechanical deformation, optically anisotropic cylinders and disks can be obtained. The cylinders are ideal to be used as micro-stirrers.

                 

To this end, we have been working on setting the experiment on the channels and make the bipolar cylinders spin by the effect of the rotating electric field. The principle of the experiment can be easily extended to the realization of selective valves and micro-pumps.
To finish, one of the ultimate goals of this project is to extend the use of microfluidics to the realization of phase diagrams.

This web page is maintained by:

Galder Cristobal-Azkarate
9 & 15 Oxford Street
Gordon McKay Laboratory, Room #519
Cambridge, MA 02138
617 496 9562

Last update 07/05/03

This work is in collaboration with