54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
8-11 April 2013, Boston, Massachusetts
AIAA 2013-1582
Phenomenological Characterization of the Fabrication of Aligned Carbon Nanotube Nanocomposites via Dielectrophoresis Under AC Electric Field
Engin Sengezer and G.D. Seidel
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA
Here we use dielectrophoresis under the application of AC electric fields as the primary fabrication technique (DEPFT) for aligned carbon nanotube (CNT)-polymer nanocomposites, and generate data sets in order to develop DEPFT fabrication models for the dispersion and orientation of CNTs. While the general understanding of how CNTs form aligned filaments under the influence of the dielectrophoretic forces and moments is well established, detailed multi-CNT-filament formation predictions of microstructure evolution from a random dispersion into this ordered structure remain intractable. As such we on characterizing the process-structure-property relationships towards the development of phenomenological fabrication models for controlling local CNT dispersion and orientation as a function of applied electric field magnitude, frequency, and exposure time. In this study, 0.03 wt %SWNTs were dispersed in a photopolymerizable monomer blend (urethane dimethacrylate (UDMA) and 1,6-hexanediol dimethacrylate (HDDMA)) using ultrasonication techniques to obtain the acrylate solution (0.03 % SWNTs / UDMA /HDDMA(9/1) solution). SWNT alignment was controlled and the SWNT-filament thickness formation was explored. In order to assess key morphological features of the as-produced SWNT-acrylate nanocomposite samples such as SWNT distribution and filament thicknesses, transmission optical microscopy has been used to observe the SWNT alignment and filament formation obtained in the resulting nanocomposite samples by digital mapping of individual overlapping images, respectively. Thus, sufficient amounts of data to construct statistically meaningful distribution functions for morphological features were obtained. The electrical properties of the as-produced SWNTs-acrylate nanocomposite samples were measured to connect the resulting structures to their respective properties.