Cross-flow microfilters with large-diameter sacrificially etched cross-sections
Cross-flow microfilters were constructed on silicon substrates using photolithography, chemical vapor deposition, and sacrificial etching. These devices consist of an array of channels with arch-shaped cross-sections approximately 50 μm tall and 140 μm wide. Pores, 5 μm in diameter, were etched through channel walls with a high packing density. The microfilters were analyzed by imaging permeate and retentate solutions down the length of the channels to determine percentages of fluorescent microbeads (diameters of 2.2 and 15.5 μm) filtered per length. A simple model using principles of Brownian motion and Monte Carlo simulation closely predicts filtration performance.
KeywordsMicrofabrication Cross-flow filtration Lab-on-a-chip Sacrificial etching
We wish to acknowledge the following for assistance in device fabrication and data gathering: Brigham Young University’s Integrated Microfabrication Laboratory and Jie Xuan. Financial support was provided by the Ira A. Fulton College of Engineering and the Micron Foundation.
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