Motion video image processing (MVIP) method for measuring microfluidic-structure interactions

In microsystem applications, many microstructures are submerged in fluid and their performances are directly influenced by the microfluidic-structure interactions. Characterizations of such interactions in microfluidic devices such as micropumps, microvalves, micro-viscometers, and biomedical related microfluidic chips, are essential to seek enhanced designs and design guidance. In this study, a hybrid microfluidic test chip with integrated microcantilever is fabricated on a polymer platform using soft lithography method for characterization of microcantilever-fluid interactions. A measurement technique based on the motion video image capture and processing (MVIP) is developed to measure the static and dynamic deflections of the microcantilever subjected to forces due to fluid within the microchannel. A peristaltic pump was used to generate fluid flows across the channel, which caused a pressure differential loading of the microstructure. The images of motion were processed to characterize the motion in terms of deflection, velocity and acceleration of the structure under different flow conditions. The validity of the proposed MIP method is illustrated through comparisons with finite element model of the microcantilever. The images acquired from the proposed MVIP method were further analyzed to estimate deflection mode shapes and natural frequencies of the microcantilever under fluid interactions.