Affiliations: Department of Mechanical and Industrial Engineering,
University of Illinois at Chicago, 842 W. Taylor St., Chicago, Illinois 60607,
USA. E-mail: aguven1@uic.edu; cmm@uic.edu | Research Resources Center, University of Illinois at
Chicago, 845 W. Taylor St., Chicago, Illinois 60607, USA | Department of Materials Science and Engineering and
A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut St.,
Philadelphia, Pennsylvania 19104, USA
Abstract: Aqueous multiphase fluids trapped in closed multiwall carbon
nanotubes are visualized with high resolution using transmission electron
microscopy (TEM). The hydrothermally synthesized nanotubes have inner diameter
of 70 nm and wall thickness 20 nm, on average. The nanotubes are hydrophilic
due to oxygen groups attached on their wall surfaces. Segregated liquid
inclusions contained in the nanotubes under high pressure can be mobilized by
heating. A resistive heating stage is utilized to heat a thin membrane inside a
nanotube, causing the membrane to evaporate slowly and eventually pinch off.
Focused electron beam heating is employed as a second means of thermal
stimulation, which results in localized heating. With the latter method,
gas/liquid interface motion is observed inside the thin channel of a carbon
nanotube. Experiments like the ones presented herein may help understand the
dynamics of fluids contained in nanoscale channels.
Keywords: Multiphase fluid, Carbon nanotubes, Electron microscopy, Interface
