Experimental Investigation of Fluid Behavior in Nanochannels
Since liquids and gases are ubiquitous in nature and participate in a wide variety of natural or man-made processes, fluid phenomena have been investigated intensively at length scales ranging from thousands of miles (oceans), to micrometers (capillary flows). In this entire regime, fluids act as a continuum, thus their behavior is governed mostly by well-established theories. At the nanoscale, however, the behavior of fluids is largely unexplored and remains rather poorly understood. To fill this gap, theoretical studies in this area have been initiated in the past decade; but these studies are still in their infancy, and lack extensive experimental data for proper validation. To this end, experimental studies on fluid behavior at the nanoscale are needed to shed light in this area, and assist in determining whether fluids act differently under extreme confinement compared to the macroscale.
The current program, which is funded by a NSF NIRT grant, investigates specific phenomena involving the behavior of multiphase aqueous fluids within cylindrical nanochannels, and more specifically carbon nanotubes synthesized with different methods. Fluid behavior at these ultrafine length scales is important for the efficient design and operation of future micro- and nano-fluidic devices. The work incorporates an array of high-resolution characterization techniques, which have the demonstrated capability to resolve liquid/gas interfaces in the interior of multiwall carbon nanotubes, and use these interfaces to trace fluid motion or phase change under extreme confinement. The results of this work have been reported in a series of articles.29-34
The proposed work targets the involvement of undergraduate students in the ongoing NIRT research. Specific tasks of the undergraduate students include the performance of fluid-filling nanotube experiments using numerous types of commercial carbon nanotubes, as well as the performance of electron-microscope characterization, ranging from imaging to chemical analysis. It is worth noting that the research, although performed on a nanoscale system, produces visual images that do not require extensive training in interpreting them. While the research is of fundamental nature, it is also directly related to several technologies such as the development of nanofluidic devices utilizing nanopipes for drug delivery, nanofluidic sensors, nanotube-reinforced composites, etc.
29. Gogotsi, Y., Libera, J., Guvenc Yazicioglu, A., and Megaridis, C. M., "In situ multiphase fluid experiments in hydrothermal carbon nanotubes," Applied Physics Letters 79:(7)1021-1023 (2001).
30. Gogotsi, Y., Naguib, N., Ye, H., Yazicioglu, A. G., Megaridis, C. M. (Ed.), Analysis of Fluid in Hydrothermal Carbon Nanotubes [The exciting World of Nanocages and Nanotubes, Proc. Electrochemical Society, PV 2002-12], The Electrochemical Society, 2002.
31. Megaridis, C. M., Yazicioglu, A. G., Libera, J. A., and Gogotsi, Y., "Attoliter fluid experiments in individual closed-end carbon nanotubes: Liquid film and fluid interface dynamics," Physics of Fluids 14: L5-L8 (2002).
32. Ye, H., Naguib, N., Gogotsi, Y., Yazicioglu, A.G., Megaridis, C.M., "Wall Structure and Surface Chemistry of Hydrothermal Carbon Nanofibres," Nanotechnology 15:232-236 (2004).
33. Yazicioglu, A. G., Megaridis, C.M., Gogotsi, Y., "Evaporative Transport of Aqueous Liquid in a Closed Carbon Nanotube: A Nano Heat Pipe?," ASME J. Heat Transfer, in press
34. Gogotsi, Y., Libera, J. A., and Yoshimura, M., "Hydrothermal synthesis of multiwall carbon nanotubes," Journal of Materials Research 15: 2591-2594 (2000).