title: Magnetic orientation of single-walled carbon nanotubes or their composites using polymer wrapping.
abstract: The magnetic orientation of single-walled carbon nanotubes (SWNTs) or the SWNT composites wrapped with polymer using poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEHPPV) as the conducting polymer were examined. The formation of SWNT/MEHPPV composites was confirmed by examining absorption and fluorescence spectra. The N,N-dimethylformamide solution of SWNT/MEHPPV composites or the aqueous solution of the shortened SWNTs was introduced dropwise onto a mica or glass plate. The magnetic processing of the composites or the SWNTs was carried out using a superconducting magnet with a horizontal direction (8 T). The AFM images indicated that the SWNT/MEHPPV composites or the SWNTs were oriented randomly without magnetic processing, while with magnetic processing (8 T), they were oriented with the tube axis of the composites or the SWNTs parallel to the magnetic field. In polarized absorption spectra of SWNT/MEHPPV composites on glass plates without magnetic processing, the absorbance due to semiconducting SWNT in the near-IR region in horizontal polarized light was almost the same as that in vertical polarized light. In contrast, with magnetic processing (8 T), the absorbance due to semiconducting SWNT in the horizontal polarization direction against the direction of magnetic field was stronger than that in the vertical polarization direction. Similar results were obtained from the polarized absorption spectra for the shortened SWNTs. These results of polarized absorption spectra also support the magnetic orientation of the SWNT/MEHPPV composites or the SWNTs. On the basis of a comparison of the composites and the SWNTs alone, the magnetic orientation of SWNT/MEHPPV composites is most likely ascribable to the anisotropy in susceptibilities of SWNTs.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yonemura
authors.affiliation: Department of Materials Physics and Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Yuuichi
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan; Center for Future Creation, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Sunao
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Tanimoto
keywords: AFM; composite material; conducting polymer; magnetic orientation; magnetic processing of single-walled carbon nanotube; magnetic susceptibility; polarized absorption spectrum; polymer wrapping