High-Resolution Evanescent PIV for Near-Wall Microfluidics

This project aims to develop and test a system concept for high-resolution evanescent wave PIV, capable of near-wall flow measurements with 100 nm resolution in-plane and better, along the surface normal direction. We will construct a simple microfluidics test apparatus and identify the most appropriate type of velocity tracer from among fluorescent particles, enhanced scattering particles, or fluorescent volume tracers. Then we will design and construct an evanescent illumination system using plasmon-resonant coatings to enhance the tracer signal, the weakness of which can be a major impediment with the small tracer sizes required. We will also perform experiments using Purdue's advanced PIV data processing techniques with these apparatus to determine system performance and characterize resolution parameters. Based on the knowledge acquired from the analysis of the data, we will determine the best system design to propose for further development in Phase II and eventual commercialization. We have identified numerous promising techniques that could be applied to advance this nascent field of near-wall velocimetry, and we will investigate the use of these both to meet our current objectives and to determine the optimal strategies for the subsequent development of the system.