Water-filled single-wall carbon nanotubes as molecular nanovalves.
It is known that at low temperature, water inside single-wall carbon nanotubes (water-SWNTs) undergoes a structural transition to form tube-like solid structures. The resulting ice NTs are hollow cylinders with diameters comparable to those of typical gas molecules. Hence, the gas-adsorption properties of ice- and water-SWNTs are of interest. Here, we carry out the first systematic investigation into the stability of water-SWNTs in various gas atmospheres below 0.1 MPa by means of electrical resistance, X-ray diffraction, NMR measurements and molecular dynamics calculations. It is found that the resistivity of water-SWNTs exhibits a significant increase in gas atmospheres below a critical temperature Tc, at which a particular type of atmospheric gas molecule enters the SWNTs in an on-off fashion. On the basis of this phenomenon, it is proposed that water-SWNTs can be used to fabricate a new type of molecular nanovalve.
Maniwa
Yutaka
Y
Department of Physics, Faculty of Science, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan. maniwa@phys.metro-u.ac.jp
Matsuda
Kazuyuki
K
Kyakuno
Haruka
H
Ogasawara
Syunsuke
S
Hibi
Toshihide
T
Kadowaki
Hiroaki
H
Suzuki
Shinzo
S
Achiba
Yohji
Y
Kataura
Hiromichi
H