The proposal was submitted under Solicitation NSF 01-157 "Nanoscale Science and Engineering," under the Nanoscale Interdisciplinary Research Team (NIRT) category. Carbon nanotubes (nanopipes) offer a unique opportunity for fundamental studies of fluid transport in the spatial regime between molecular and continuum behavior. This research includes: (a) fabrication, characterization, and modification of carbon nanopipes, (b) performance of chemical and fluidic experiments, and (c) fabrication of experimental setups that would allow transport and measurements of various liquid flows in a controlled fashion. Both actuation and imaging of the fluid are done in a transmission electron microscope, and offer a unique opportunity for studying the behavior of fluids in nanosize channels at conditions corresponding to sub-, near- or super-critical regions of the thermodynamic diagram. The hydrothermal growth technique will be optimized to produce desired tube structure and geometry (internal/external diameter, length, and shape) for incorporation into experimental devices that allow the transmission of liquids through nanotubes. Fluid behavior in channels ranging from 5 to 100 nm in diameter will be investigated, both by following the dynamic response of visualized fluid interfaces to external thermal stimuli and by well controlled experiments, in which pure liquids and liquids laden with macromolecules will be transmitted through the tubes. The chemistry of high-temperature interactions between carbon nanopipes and aqueous fluids will be studied. Chemical modification, metallization, and opening of nanopipes will be done using bipolar electrochemistry. The experimental work will be supplemented by modeling based on parallel molecular dynamics simulations. It is believed that the proposed research will advance the fundamental understanding needed for the design and fabrication of a new generation of nanofluidic devices, such as nano-pumps, chemical factories on a chip, biochips, and nano-analytical systems. The research team will also coordinate and expand the existing education and outreach activities of the individual investigators into a cohesive and wide-ranging program. The work involves investigators at Drexel, the University of Pennsylvania, and the University of Illinois at Chicago. NSF support is being provided by the Chemical and Transport Systems Division and the Design, Manufacturing and Industrial Innovation Division in the Engineering Directorate, and by the Chemistry Division in the Mathematical and Physical Sciences Directorate.
