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Nanocomposite Material, Liquid Crystal-Aerosil Particles: Dielectric and Photon Correlation Spectroscopy Investigations

Published online by Cambridge University Press:  21 February 2011

F.M. Aliev  and
G.P. Sinha
F.M. Aliev
Affiliation:
Dept. of Physics, University of Puerto Rico, San Juan, PR 00931-3343, USA
G.P. Sinha
Affiliation:
Dept. of Physics, University of Puerto Rico, San Juan, PR 00931-3343, USA
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Abstract

Nematic liquid crystal filled with Aerosil particles prospective inorganic-organic nanocom-posite material for optoelectronic application has been investigated by broadband dielectric spectroscopy (BDS) and photon correlation spectroscopy (PCS). The aerosil particles of diameter ≈ 10 nm in filled nematic liquid crystals form a network structure with linear size of LC domains about 250 nm and with random distribution of the director orientation of each domain. This material has a very developed liquid crystal-solid particle interface that makes the role of the surface layers of LC important in the determination of the properties of the material. BDS provides information on reorientational motion of polar molecules of liquid crystal while PCS probes dynamics of collective modes associated with director fluctuations. We found that the properties of 5CB are considerably affected by the network. Two bulk-like dielectric modes due to the rotation of molecules around short axes and the tumbling motion were observed in filled 5CB. Additionally, a low frequency relaxation process and dispersion of dielectric permittivity due to conductivity were observed. The treatment of the surface of filling particles has strongest influence on the properties of the slow process and it is less important for molecular modes. PCS experiment shows that two new relaxation processes appear in filled 5CB in addition to the director fluctuations process in bulk.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 581: Symposium F – Nanophase & Nanocomposite Materials II , 1999 , 309
Copyright
Copyright © Materials Research Society 2000

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References

REFERENCES

1. Drzaic, P.S., Liquid Crystal Dispersions, (World Scientific, Singapore, 1995).Google Scholar
2. Liquid Crystals in Complex Geometries, edited by Crawford, G.P. and Zumer, S. (Taylor and Francis, London, 1996).Google Scholar
3. Kreuzer, M., Tschudi, T., Jeu, W.H. de, and Eidenschink, R., Appl. Phys. Lett. 62, 1712 (1993).Google Scholar
4. Kreuzer, M. and Eidenschink, R. in Liquid Crystals in Complex Geometries, edited by Crawford, G.P. and Zumer, S. (Taylor & Francis, London, 1996), pp. 307–324.Google Scholar
5. Zhou, B., Iannacchione, G.S., Garland, C.W., and Bellini, T., Phys. Rev. E 55, 2962 (1997).Google Scholar
6. Bellini, T., Clark, N.A., Degiorgio, V., Mantegazza, F., and Natale, G., Phys. Rev. E. 57, 2996 (1998).Google Scholar
7. Iannacchione, G.S., Garland, C.W., Mang, J.T., and Rieker, T.P., Phys. Rev. E 58, 5966 (1998).Google Scholar
8. Aliev, F., Kreuzer, M., Tabiryan, N., and Zel'dovich, B., Mol. Cryst. Liq. Cryst. 320, 173 (1998).Google Scholar
9. Tschierske, S., Yaroshchuk, O.V., and Kresse, H., Cryst. Res. Technol. 30, 571 (1995).Google Scholar
10. Abd-El-Messiah, S.L., Werner, J., Schmalfuss, H., Weissflog, W. and Kresse, H., Liq. Cryst. 26, 535 (1999).Google Scholar
11. Cummins, P.G., Danmur, D.A., and Laidler, D.A., Mol. Cryst. Liq. Cryst. 30, 109 (1975).Google Scholar
12. Lippens, D., Parneix, J.P., and Chapoton, A., J. de Phys. 38, 1465 (1977).Google Scholar
13. Wacrenier, J.M., Druon, C., and Lippens, D., Mol. Phys. 43, 97 (1981).Google Scholar
14. Bose, T.K., Chahine, R., Merabet, M., and Thoen, J., J. de Phys. 45, 11329 (1984).Google Scholar
15. Bose, T. K., Campbell, B., Yagihara, S., and Thoen, J., Phys. Rev. A 36, 5767 (1987).Google Scholar
16. Rozanski, S.R., Stanarius, R., Groothues, H., and Kremer, F., Liquid Crystals 20, 59 (1996).Google Scholar
17. Sinha, G.P. and Aliev, F.M., Phys. Rev. E 58, 2001 (1998).Google Scholar
18. Havriliak, S. and Negami, S., Polymer 8, 101 (1967).Google Scholar
19. Gennes, P.G. de and Prost, J., The Physics of Liquid Crystals, second ed., (Clarendon Press, Oxford 1993).Google Scholar