title: Water-filled single-wall carbon nanotubes as molecular nanovalves.
abstract: 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.
authors.affiliation: Department of Physics, Faculty of Science, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan. maniwa@phys.metro-u.ac.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Maniwa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Matsuda
authors.forename: Haruka
authors.initials: H
authors.lastname: Kyakuno
authors.forename: Syunsuke
authors.initials: S
authors.lastname: Ogasawara
authors.forename: Toshihide
authors.initials: T
authors.lastname: Hibi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kadowaki
authors.forename: Shinzo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yohji
authors.initials: Y
authors.lastname: Achiba
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kataura