Issue Eur. Phys. J. Appl. Phys. Volume 42, Number 3, June 2008 Page(s) 241 - 246 Section Nanomaterials and Nanotechnologies DOI 10.1051/epjap:2008069 Published online 30 April 2008

Eur. Phys. J. Appl. Phys. 42, 241-246 (2008)
DOI: 10.1051/epjap:2008069

Alignment of MWCNTs in polymer composites by dielectrophoresis

M.-W. Wang¹, T.-C. Hsu¹ and C.-H. Weng<sup>2

1</sup>  Department of Mechanical Engineering, Oriental Institute of Technology, Pan-Chiao, Taipei Hsien 220, Taiwan
²  Institute of Mechanical Engineering, Yuan-Ze University, Chung-Li, Tao-Yuan Hsien 320, Taiwan

avian@mail.oit.edu.tw

Received: 22 August 2007 / Received in final form: 26 January 2008 / Accepted: 28 February 2008 / Published online: 30 April 2008

Abstract
Successful structural reinforcement of polymer matrices by carbon nanotube has been broadly applied where significant improvement of mechanical properties was achieved at a low carbon nanotube loading rate. The notion of the mechanical properties of aligned composites are better than random ones has been proofed and demonstrated whereas the concept is not easy to implement through carbon nanotube polymer composites by the conventional techniques. Here, we introduce a novel practice to actively align and network the multi-wall carbon nanotubes (MWCNTs) in hot melting high density polyester (HDPE) matrix. In this process, MWCNTs were aligned via AC electric field which induced dipolar interactions among the nanotubes in a hot melting matrix and followed by immobilization by cooling curing matrix under continued application of the anisotropic electric field. In situ SEM verified the electrostatic stabilization of the MWCNTs in the dispersion while the orientation and agglomeration are caused by the dielectrophoretic force. Alignment of MWCNTs was controlled as a function of magnitude, frequency, and application time of the applied dielectrophoresis. In the present work, MWCNTs are not only aligned along the field, but also migrate laterally to form thickness. Eventually, the actively aligned MWCNTs would amplify the hardness and wear-resisting property.

PACS
51.50.+v - Electrical properties.
52.80.Wq - Discharge in liquids and solids.

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