Mixer electrokinetic instability

It is customary, mainly owing to fabrication needs, that for biological applications chip-like systems with two-layer construction are used, thus being in-plane. Mixers used for the same purposes have to adjust to this fact. Since multi-lamination typically needs several layers to achieve the proper feeding pathways, other mixers with simpler designs such as the electrokinetic instability mixer need to be applied [25], In contrast, chemical applications, where the mixer is only associated with part of the plant and not integrated in a small, flat device, do not pose such preferences indeed, multi-layer microfabrication architectures have been used. 

Active Mixer, Fig. 3 (a) Configuration of electrokinetic instability mixer and (b) time-stamped experimental images of mixing process... 

Mixer 3 [M 3] Electrokinetic Instability Electroosmotic Flow Micro Mixer, First-generation Device... 

Electrokinetic instability electroosmotic flow mixer, lst-generation device... 

Figure 1.7 Design of an electrokinetic instability EOF micro mixer, first-generation device [25] (by courtesy of ACS).

Figure 1.8 Design of an electrokinetic instability micro mixer, second-generation device, based on the results obtained with the first design given in Figure 1.7. The electrokinetic instability is confined to the square mixing chamber shown in the center of the schematic and, to a small extent, to fluid channel regions attached to it [25] (by courtesy of ACS).

Mixer 5 [M 5] Electrokinetic Instability Micro Mixer by Zeta-potential Variation... 

Mixer type Electrokinetic instability micro mixer with zeta potential variation Shielding electrode channel width, depth 250 pm, 25 pm... 

Figure 1.13 Ensemble-averaged temporal evolution of voxel-averaged spatial intensity PDFs for the electrokinetic instability micro mixer, second-generation device. Each ensemble consists of nine realizations.

Figure 1.14 Two-dimensional power spectra of various mixing chamber images for the electrokinetic instability micro mixer, second-generation device, (a) Large frequency components along the vertical direction owing to the initial layered distribution of the dye. (b) Larger spatial frequencies are introduced by the EKI stirring within the chamber, (c) The attenuation of large spatial frequencies corresponds to a nearly homogeneous intensity profile [25] (by courtesy of ACS).

An active mixer based on an oscillating EOF induced by sinusoidal voltage ( 100 Hz, 100 V/mm) was devised and modeled for mixing of fluorescein with electrolyte solutions. This is termed as electrokinetic-instability micromixing, which is essentially a flow fluctuation phenomenon created by rapidly reversing the flow. Various microchips materials (PDMS, PMMA, and glass) and various electrolytes (borate, HEPES buffers) have been used to evaluate this method of micromixing [480]. 

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