Theoretical and Experimental Analyses of Liquid Transport in Fluidic Systems with Micro/Nanostructured Surfaces: Toward Applications in Separation Processes

This doctoral dissertation involves the theoretical and experimental analyses of liquid transport in fluidic devices that have surfaces with either natural or synthetic micro/ nanoscale structures that significantly affect interfacial processes such as wetting and spreading, imbibition and drainage, and liquid transport driven by pressure and/or capillary forces. The first research project of this dissertation involves research work performed at the National Synchrotron Light Source (NSLS-II) of Brookhaven National Laboratory (BNL) where the X-ray Photon Correlation Spectroscopy (XPCS) techniques have been employed to characterize flow velocity profiles and rheological properties of colloidal fluids. A Fourier decomposition technique and a multivariable optimization algorithm were developed and applied to determine the flow velocity profiles and mass diffusivity from the intensity autocorrelation function obtained from the XPCS experiments. The second research project of this dissertation involves the design, fabrication, and characterization of a fluidic diode device for potential application in water-oil separation and microfluidic handling. Theoretical and experimental results indicate that a simple capillary device with micro/nanopatterned glass surfaces can be employed as a fluidic diode due to the presence of a large surface energy barrier preventing the transport of specific fluid pairs. The scientific and technical knowledge gained from the projects performed for this doctoral dissertation can have a significant impact on the design of novel micro/nanofluidic devices for passive separation, detection, and actuation.