Title: Dielectrophoretic modeling of the dynamic carbon nanotube network formation in viscous media under alternating current electric fields

A.I. Oliva-Aviles,
Centro de Investigacio´n y de Estudios Avanzados, Unidad Merida, Departamento de Fisica Aplicada, A.P. 73-Cordemex, 97310 Merida, Yucatan, Mexico
F Avilés,
Centro de Investigación Científica de Yucatán A.C, Unidad de Materiales, Calle 43 No. 130 Colonia Chuburná de Hidalgo, 97200, Mérida, Yucatán, México
V. Sosa,
Centro de Investigacio´n y de Estudios Avanzados, Unidad Merida, Departamento de Fisica Aplicada, A.P. 73-Cordemex, 97310 Merida, Yucatan, Mexico
Gary Don Seidel,
Dept. of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, 228 Randolph Hall (0203) Blacksburg, VA 24061, USA

Carbon -- 2014 -- Vol 69 pp 342-354

Abstract
The dynamic formation of carbon nanotube (CNT) networks in liquids under the application of an alternating current electric field is investigated using the effective dipole modeling approach. Three mechanisms are investigated by a set of three independent nonlinear differential equations derived from dielectrophoretic theory, viz. CNT rotation, CNT-to-CNT Coulombic interactions, and CNT migration towards an electrode. The models consider the effect of the electric field magnitude and frequency, the CNT’s concentration and aspect ratio, and the viscosity of the surrounding medium. A layer at the CNT/liquid interface is included and the effect of such layer’s permittivity, electrical conductivity and thickness is investigated. Modeling predictions allow the reconstruction of the dynamic sequence of events leading to an aligned CNT network, which strongly depends on the CNT’s aspect ratio and concentration. Experimental trends regarding the effect of frequency can only be captured by considering an interface layer in the model.

Key words: Polymer nanocomposites, dielectrophoresis, carbon nanotube