Foil definition for optimizing the shape of microfabricated columns for capillary electrochromatography

A novel design approach for optimizing the shape of the microfabricated pillar columns [1] for capillary electrochromatography (CEC) is presented. Applying this optimization approach, a new foil shape definition was introduced. Several design alternatives were evaluated starting from typical NACA 4-digit series symmetric airfoil definition. In order to avoid stagnant regions over the leading edge for NACA airfoil, the maximum thickness point was defined at the center of the chord. Then this shape was defined as the intersection of two parent circles to create the same geometry with simpler definition. As a final step of the optimization, a custom foil shape was obtained by fitting the 4 ^th order polynomial, which was obtained from typical NACA 4-digit series, according to the defined boundary conditions. Microfluidic flow simulations were performed for electroosmotic flow (EOF) case for evaluating the performance of the foil definitions over other popular geometries (diamond and hexagon) from literature [2]. For electric field of 100 V/cm and same length and width, the custom foil shape yielded a plate height value of 2.76 urn, while 2.85 μm was obtained with hexagon as being the lowest value among other alternatives from the literature.