MSCE  Vol.3 No.1 , January 2015
Enhancement of the Electromagnetic Wave Shielding Effectiveness by Geometry-Controlled Carbon Coils
ABSTRACT

Carbon microcoils were deposited onto Al2O3 substrates using C2H2/H2 as source gases and SF6 as an incorporated additive gas in a thermal chemical vapor deposition system. At as-grown state, the carbon coils (d-CCs) show the diverse geometry. The geometry-controlled carbon microcoils (g-CMCs) could be obtained by manipulating the injection time of SF6 in C2H2 source gas. The d-CCs with polyurethane (PU) composite (d-CC@PU) and the g-CMCs with PU composite (g-CMC@PU) were obtained by dispersing d-CCs and g-CMCs in PU, respectively. The electromagnetic wave shielding properties of d-CC@PU and g-CMC@PU composites were investigated in the frequency range of 0.25 - 4.0 GHz. The shielding effectiveness (SE) of d-CC@PU and g-CMC@PU composites were measured and discussed according to the weight percent of d-CCs and g-CMCs in the composites with the thickness of the composites layers. On the whole frequency range in this work, the SE of g-CMC@PU composites was higher than those of d-CC@PU composites, irrespective of the weight percent of carbon coils in the composites and the layer thickness. Furthermore, we confirmed that the absorption mechanism, instead of the reflection mechanism, seemed to play the critical role to shield the EMI for not only the g-CMC@PU composites but also the d-CC@PU composites.


Cite this paper
Kang, G. , Kim, S. and Kim, S. (2015) Enhancement of the Electromagnetic Wave Shielding Effectiveness by Geometry-Controlled Carbon Coils. Journal of Materials Science and Chemical Engineering, 3, 37-44. doi: 10.4236/msce.2015.31006.
References
[1]   Amelinckx, S., Zhang, X.B., Bernaerts, D., Zhang, X.F., Ivanov, V. and Nagy, J.B. (1996) A Formation Mechanism for Catalytically Grown Helix-Shaped Graphite Nanotubes. Science, 265, 635-639.

[2]   Zhao, D.-L. and Shen, Z.-M. (2008) Preparation and Microwave Absorption Properties of Carbon Nanocoils. Materials Letters, 62, 3704-3706. http://dx.doi.org/10.1016/j.matlet.2008.04.032

[3]   Motojima, S., Hoshiya, S. and Hishikawa, Y. (2003) Electromagnetic Wave Absorption Properties of Carbon Microcoils/PMMA Composite Beads in W Bands. Carbon, 41, 2658-2660. http://dx.doi.org/10.1016/S0008-6223(03)00292-6

[4]   Yang, L., Gupta, M.C., Dudley, K.L. and Lawrence, R.W. (2005) Novel Carbon Nanotube-Polystyrene Foam Composites for Electromagnetic Interference Shielding. Nano Letters, 5, 2131-2135. http://dx.doi.org/10.1021/nl051375r

[5]   Wu, J. and Chung, D.D.L. (2003) Improving Colloidal Graphite for Electromagnetic Interference Shielding Using 0.1 ?m Diameter Carbon Filaments. Carbon, 41, 1313-1315. http://dx.doi.org/10.1016/S0008-6223(03)00033-2?

[6]   Shaikjee, A. and Coville, N.J. (2012) The Synthesis, Properties and Uses of Carbon Materials with Helical Morphology. Journal of Advanced Research, 3, 195-223. http://dx.doi.org/10.1016/j.jare.2011.05.007

[7]   Akagi, K., Tamura, R., Tsukada, M., Itoh, S. and Ihara, S. (1995) Electronic Structure of Helically Coiled Cage of Graphitic Carbon. Physical Review Letters, 74, 2307-2310. http://dx.doi.org/10.1103/PhysRevLett.74.2307

[8]   Eum, J.-H., Kim, S.-H., Yi, S.S. and Jang, K. (2012) Large-Scale Synthesis of the Controlled-Geometry Carbon Coils by the Manipulation of the SF6 Gas Flow Injection Time. Journal of Nanoscience and Nanotechnology, 12, 4397-4402. http://dx.doi.org/10.1166/jnn.2012.5940

[9]   Eum, J.-H., Jeon, Y.-C. and Kim, S.-H. (2012) Effect of Gas Phase Composition Cycling on/off Modulation Numbers of C2H2/SF6 Flows on the Formation of Geometrically Controlled Carbon Coil. Journal of Nanoscience and Nanotechnology, 12, 6100-6106. http://dx.doi.org/10.1166/jnn.2012.6342

[10]   Jeon, Y.-C., Eum, J.-H., Kim, S.-H., Park, J.-C. and Ahn, S.I. (2012) Ef-fect of the on/off Cycling Modulation Time Ratio of C2H2/SF6 Flows on the Formation of Geometrically Controlled Carbon Coils. Journal of Nanomaterials, 2012, Article ID: 908961.

[11]   Wu, J. and Chung, D.D.L. (2001) Increasing the Electromagnetic Interference Shielding Effectiveness of Carbon Fiber Polymer-Matrix Composite by Using Activated Carbon Fibers. Carbon, 40, 445-467. http://dx.doi.org/10.1016/S0008-6223(01)00133-6

[12]   Sau, K.P., Chaki, T.K., Chakraborty, A. and Khastgir, D. (1997) Electromagnetic Interference Shielding by Carbon Black and Carbon Fiber Filled Rubber Composite. Plastics Rubber Comp. Process. Appl., 26, 291-297.

[13]   Yang, S., Lozano, K., Lomeli, A., Foltz, H.D. and Jones, R. (2005) Electromagnetic Interference Shielding Effectiveness of Carbon Nanofiber/LCP Composites. Composites: Part A, 36, 691-697. http://dx.doi.org/10.1016/j.compositesa.2004.07.009

[14]   Simon, R.M. (1981) EMI Shielding through Conductive Plastics. Polymer-Plastics Technology and Engineering, 17, 1-10. http://dx.doi.org/10.1080/03602558108067695

 
 
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