A dielectrophoretic oil filter concept utilizing three-dimensional electrode geometries for electric and flow field shaping is introduced. Dielectrophoretic separation systems that incorporate planar microelectrodes cannot effectively filter large amounts of fluids because the dielectrophoretic force rapidly decays as the distance from the electrodes increases. 3D electrode designs for flow-through dielectrophoretic separation/concentration/filtration systems are advantageous because 1) The 3D electrodes extend the electric field within the fluid. 2) The electrodes can be designed so that the velocity field as well as the electric field is shaped for maximum efficiency. and 3) Filtration of particles that are too small to be physically filtered is possible. Three novel electrode designs that are not based on 2D electrode designs are introduced. Initial experimental results from particle count analysis that suggest that a reduction of up to 90% of particulate contaminants could be achieved are presented (It is important to note that the standard deviation was large due to the small number of particles within view and the uneven distribution of particles within the oil).
A novel particle-based lithography is proposed. In this approach a particle moving in a liquid in contact with a light-sensitive
substrate creates traces on that substrate (for example on a photoresist or on a photographic film). The light-emitting particle causes photochemical/photoelectric changes in the light-sensitive substrate, creating a latent image. A
group of these particles can be used to write many features on the same substrate in a parallel manner. We investigate
the use of electrokinetic forces to move the particles over the light-sensitive substrate. We also report on the use of
high-aspect-ratio carbon MEMS (C-MEMS) electrodes as 3D dielectrophoretic traps for the light-emitting particles and
investigate the feasibility of using these carbon electrodes to manipulate the light-emitting particles to trace sub-micron
patterns on a light-sensitive surface. We propose two types of particle-based lithography schemes and discuss
applicable scaling laws. Feasibility experiments were carried out using microscale devices.