Article ID Journal Published Year Pages File Type
1416471 Carbon 2011 8 Pages PDF
Abstract

Maghemite (γ-Fe2O3)/multi-walled carbon nanotubes (MWCNTs) hybrid-materials were synthesized and their anisotropic electrical conductivities as a result of their alignment in a polymer matrix under an external magnetic field were investigated. The tethering of γ-Fe2O3 nanoparticles on the surface of MWCNT was achieved by a modified sol–gel reaction, where sodium dodecylbenzene sulfonate (NaDDBS) was used in order to inhibit the formation of a 3D iron oxide gel. These hybrid-materials, specifically, magnetized multi-walled carbon nanotubes (m-MWCNTs) were readily aligned parallel to the direction of a magnetic field even when using a relatively weak magnetic field. The conductivity of the epoxy composites formed in this manner increased with increasing m-MWCNT mass fraction in the polymer matrix. Furthermore, the conductivities parallel to the direction of magnetic field were higher than those in the perpendicular direction, indicating that the alignment of the m-MWCNT contributed to the enhancement of the anisotropic electrical properties of the composites in the direction of alignment.

Graphical abstractThe application of a low magnetic field (0.3 T) to a suspension of magnetic carbon nanotubes (m-CNTs) in an epoxy fluid induced the facile alignment of the m-CNTs in the direction parallel to the magnetic field. These resulting composite materials exhibited anisotropic electrical conductivities that were enhanced with respect to the magnetic field direction.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► γ-Fe2O3 nanoparticles were tethered to MWCNT to form magnetic carbon nanotubes, m-MWCNTs. ► Magnetic MWCNT in an epoxy matrix readily aligned in the direction of an externally applied magnetic field. ► The conductivities of the resulting composites parallel to the direction of magnetic field were higher than those in the perpendicular direction.

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Physical Sciences and Engineering Energy Energy (General)
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