Optical anisotropy of carbon nano-fiber/silica composite films prepared under high magnetic field

抄録

Carbon/silica composite films were prepared from colloidal silica aqueous solution in which vapour grown carbon nano-fibers were dispersed. The orientation of nano-fibers was attempted by dip-coating substrates under high magnetic field up to 10 T. The fibers started to align along the direction of magnetic field below 1 T. The degree of orientation was saturated at about 6 T. The anisotropic susceptibility, Δχ = χ_// − χ_⊥, was estimated to be (3.05 ± 1.10) × 10⁻⁷ cm³/mol from the fitting of numerical simulation. Optical anisotropy, the ratio between transmittances of light polarized perpendicular to and parallel to the direction of fiber orientation, increased immediately in the films prepared under applied fields below 1 T and almost saturated above 1 T. The optical anisotropy was in good agreement with the behaviour of magnetic orientation of fibers.