Download or read book Understanding the Transport of Nanoparticles in Microchannel Based Model Porous Media written by Kai He and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, nanoparticle dispersions have been explored to improve the exploration and production of sub-surface hydrocarbons. To address that effort it is critical to fundamentally understand the dynamics and transport of nanoparticles in porous media. Natural porous media are heterogeneous in confinement, connectivity and surface chemistry resulting in different physical mechanisms for transport. Thus, understanding the dynamics and transport of nanoparticles in model porous media is important. In this work, an effective methodology for improved understanding of diffusion and transport mechanisms of nanoparticles in model porous media has been developed, using a combination of nanofabrication and optical microscopy based techniques - differential dynamics microscopy (DDM) and single particle tracking (SPT). First, the diffusive dynamics of 100 nm to 400 nm diameter polystyrene nanoparticles dispersed in water were examined using DDM. The diffusion coefficients measured by DDM were in excellent agreement with those measured by dynamic light scattering, indicating that DDM is a valid tool to investigate the dynamics of nanoparticles. Next, the confinement effect on the diffusive dynamics of nanoparticles was investigated using DDM and SPT. Arrays of nanoposts of diameter 500 nm and spacing ranging from 0.4 to 10 mm were fabricated to confine 200-400 nm diameter nanoparticles. Two effects of confinement imposed by the cylindrical posts were found: slowing diffusive dynamics of nanoparticles and inducing emergence of multiple relaxation times and further modifying the relaxation process. Results also showed that under modest confinement nanoparticles remained diffusive; while under extreme confinement diffusion became anomalous. Finally, transport of nanoparticles through model porous media was probed using SPT. Microchannels with cylindrical post arrays of post spacing ranging from 0.8 to 2 mm were fabricated, nanoparticles were then injected into the microchannel with Re