Kim Il Tae, Tannenbaum Allen, Tannenbaum Rina
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA ; School of Polymer, Textile, and Fiber Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Carbon N Y. 2011 Jan;49(1):54-61. doi: 10.1016/j.carbon.2010.08.041.
Maghemite (γ-Fe(2)O(3))/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-Fe(2)O(3) 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.
合成了磁赤铁矿（γ-Fe₂O₃）/多壁碳纳米管（MWCNTs）复合材料，并研究了它们在外部磁场作用下在聚合物基体中排列所导致的各向异性电导率。通过改进的溶胶-凝胶反应实现了γ-Fe₂O₃纳米颗粒在MWCNT表面的 tethering，其中使用十二烷基苯磺酸钠（NaDDBS）以抑制三维氧化铁凝胶的形成。这些复合材料，具体而言，即使在使用相对较弱的磁场时，磁化的多壁碳纳米管（m-MWCNTs）也很容易与磁场方向平行排列。以这种方式形成的环氧复合材料的电导率随着聚合物基体中m-MWCNT质量分数的增加而增加。此外，平行于磁场方向的电导率高于垂直方向的电导率，这表明m-MWCNT的排列有助于增强复合材料在排列方向上的各向异性电学性能。
