Plasma Coating and Enhanced Dispersion of Carbon Nanotubes
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Q10.7.1
Plasma Coating and Enhanced Dispersion of Carbon Nanotubes Peng He, Jie Lian1, Donglu Shi, Lumin Wang1, Wim van Ooij, David Mast2, W. Z. Li3, and Z. F. Ren3 Dept. of Chemical and Materials Engineering, 2Dept. of Physics, University of Cincinnati Cincinnati, OH 45221 1 Dept. of Nuclear Engineering and Radiological Science, University of Michigan Ann Arbor, MI 48109 3 Dept. of Physics, Boston College, MA 02467 ABSTRACT Ultrathin polymer films have been deposited on both multi-wall and aligned carbon nanotubes using a plasma polymerization treatment. TEM experimental results showed that a thin film of polystyrene layer (several nanometers) was uniformly deposited on the surfaces of the nanotubes including inner wall surfaces of the multi-wall nanotubes. The coated multi-wall nanotubes were mixed in polymer solutions for studying the effects of plasma coating on dispersion. It was found that the dispersion of multi-wall carbon nanotubes in polystyrene composite was significantly improved. The deposition mechanisms and the effects of plasma treatment parameters are discussed. INTRODUCTION Recently, it has been shown in laboratory scale tests that the physical properties and performance of composite materials can be significantly improved by the addition of small percentages (~2%) of carbon nanotube particles [1-5]. However, there have not been many successful large-scale tests using a wide variety of soft phase materials that show the advantage of using nanotubes as fillers over traditional carbon fibers. The main problem is in dispersing the nanotubes and creating a strong interface between the nanaotube and the polymer matrix. This strong interface between the nanaotube and the polymer matrix is essential to transfer the load from the matrix to the nanotubes and thereby to enhance the mechanical properties of the composite. A crucial reason for these difficulties is that the nanotubes are atomically smooth and have nearly the same diameters and aspect ratios as polymer chains. In addition, the as-produced nanotubes usually form as aggregates that behave differently in response to a load as compared to individual nanotubes. To maximize the advantage of nanotubes as reinforcing particles in high strength composites, the aggregates need to be broken up and dispersed or crosslinked to prevent slippage. In our previous works we developed new nano structures by a unique plasma treatment for the synthesis of polymer composites [6-10]. The unique properties required in these composites have been shown to be best achieved by our plasma method. The goal of the research is to enhance nanotube dispersion in the polymer and the interfacial bonding between the carbon nanotubes and matrix by depositing ultrathin films on the surfaces of the nanotubes, and to study the fundamental interfacial structures related to the bonding mechanisms. In this report, we will show some recent experimental results on coating of various types of carbon nanotubes and their modified dispersion properties.
Q10.7.2
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