title: Helical superstructures of fullerene peapods and empty single-walled carbon nanotubes formed in water.
abstract: Aqueous dispersions of fullerene C70-filled carbon nanotubes (C70@SWNTs or peapods) and empty single-walled carbon nanotubes (empty SWNTs) were prepared with the aid of trimethyl-(2-oxo-2-pyrene-1-yl-ethyl)-ammonium bromide (1), which is a carbon nanotube solubilizer. This is the first report describing the preparation and characterization of the transparent dispersion/dissolution of the peapods. The UV-vis-near-IR spectra of C70@SWNTs-1 and empty SWNTs-1 were almost identical. We found by means of transmission electron microscopy and atomic force microscopy that the empty SWNTs and C70-peapods form helical nanostructures in the shapes of rings, irregular rings, lassos, handcuffs, catenanes, pseudorotaxanes, and figure-eight structures. The mechanism of the superstructure formation has been discussed in relation to the unique characteristics of stiff polymer chains with the aid of an off-lattice Monte Carlo simulation.
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 812-8581, Japan. nakashima-tcm@mbox.nc.kyushu-u.ac.jp
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Nakashima
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tomonari
authors.forename: Hiroto
authors.initials: H
authors.lastname: Murakami
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kataura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sakaue
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshikawa