Moderate anisotropy in the electrical conductivity of bulk MWCNT/epoxy composites

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• 作者：Aron Dombovari ; Niina Halonen ; Andras Sapi ; Maria Szabo ; Geza Toth ; Jani Mä ; klin ; Krisztian Kordas ; Jari Juuti ; Heli Jantunen ; Akos Kukovecz ; Zoltan Konya
• 刊名：Carbon
• 出版年：2010
• 出版时间：June 2010
• 年：2010
• 卷：48
• 期：7
• 页码：1918-1925
• 全文大小：809 K

文摘

Bulk aligned multi-walled carbon nanotube films and their epoxy composites were prepared and their DC and AC conductivity studied. Nanotube films of up to 2 mm thickness were grown by catalytic chemical vapor deposition. Composites of nanotubes were made by infiltrating the films with a commercial epoxy. DC electrical resistivities in the axial direction of as-grown and purified films were found to be 1.2 Ωmm and 3.4 Ωmm, respectively. For the transverse direction the resistivity values were higher only with a factor of 2. In the case of composites, anisotropy is more pronounced showing more than an order of magnitude higher resistivity in the transverse direction (71.4 Ωmm) as compared to the axial value (4.2 Ωmm). AC behavior of the films investigated between 1 MHz and 3 GHz shows the presence of inductive and capacitive components at frequencies above 100 MHz. The moderate anisotropy for both DC and AC electrical properties are explained on the basis of the films’ structure combined with percolation theory and equivalent circuit models.