Microwave absorption in liquid crystals and carbon nanotubes

J. N. Dahiya; Ragu Athinarayanan; J. A. Roberts; J. M. Tour; D. W. Price Jr.

doi:10.1117/12.557830

7 April 2004 Microwave absorption in liquid crystals and carbon nanotubes

J. N. Dahiya, Ragu Athinarayanan, J. A. Roberts, J. M. Tour, D. W. Price Jr.

Proceedings Volume 5445, Microwave and Optical Technology 2003; (2004) https://doi.org/10.1117/12.557830
Event: Microwave and Optical Technology 2003, 2003, Ostrava, Czech Republic

Abstract

A cylindrical microwave resonant cavity in TE₀₁₁ mode in a microwave spectrometer is used to identify phase transitions in liquid crystal 4-methoxybenzilidene-4'-butylanine (MBBA). The microwave dielectric response in this liquid crystal is studied at microwave frequencies of 9.52 and 10.1 GHz. The method of cooling the sample as described in this paper is very effective in producing the metastable modification in this liquid crystal. Dielectric relaxation in this molecule is studied by using Debye's theory of polar molecules, and Slater's perturbation equations are used to calculate the real and imaginary parts of the dielectric constant. The microwave spectrometer is also used to study the behavior of nanotubes as a function of frequency. There seems to be a very high absorption of microwaves at certain frequencies in samples of carbon nanotubes studied in this experiment. We have attempted to calculate the rates of absorbance of microwaves first by using sample of pure polycarbonate and then compared the results obtained with various blends. The reduction in the amplitude and the overall attenuation of the microwave signal applied is the measure of the absorption of microwaves in these samples.

Citation Download Citation

J. N. Dahiya, Ragu Athinarayanan, J. A. Roberts, J. M. Tour, and D. W. Price Jr. "Microwave absorption in liquid crystals and carbon nanotubes", Proc. SPIE 5445, Microwave and Optical Technology 2003, (7 April 2004); https://doi.org/10.1117/12.557830

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