Skip to main content Accessibility help
×
Home

Slow Dynamics and Glass-Like Behavior of Liquid Crystals Dispersed in Nanoporous Media

  • F. M. Aliev (a1) and G. P. Sinha (a1)

Abstract

We have investigated the dynamic behavior of liquid crystals (LC), which are not glass formers when in bulk form, confined in porous matrices with randomly oriented, interconnected pores as well as in parallel cylindrical pores with different pore sizes by photon correlation (time range: 20 ns-103s) and dielectric spectroscopies (frequencies: 0.1 Hz-1.5GHz). We observed that in random pores (pore size is 10 nm and 100 nm) LC does not crystallize at temperatures about 25° C below bulk crystallization temperature and the non-Debye relaxational processes studied by both photon correlation and dielectric experiments were found not to be frozen. Slow relaxational process which does not exist in bulk LC and a broad spectrum of relaxation times (10−8 − 10)s appear not only for LC in random pores but in cylindrical pores as well. However in matrices with random pores of 100 Å, glass-like behavior of slow mode (τ > 1ms) was observed. The relaxation time (determined in photon correlation experiment) of this slow process strongly increases when temperature decreases from 300 K up to 270 K varying from 0.2ms to 14 s and it's temperature dependence is described by the Vogel-Fulcher law.

Copyright

References

Hide All
1. Molecular Dynamics in Restricted Geometries, ed. by Klafter, J. and Drake, J.M. (Wiley, New York, 1989).
2. Schuller, J., Mel'nichenko, Yu.B., Richert, R., and Fischer, E.W., Phys. Rev. Lett. 73, 2224 (1994).
3. Arndt, M. and Kremer, F. in: Dynamics in Small Confining Systems II, edited by Drake, J.M., Klafter, J., Kopelman, R., Troian, S.M., (Mater. Res. Soc. Proc. 363, Pittsburgh, PA 1995), p. 259263.
4. Mel'nichenko, Yu., Schuller, J., Richert, R., Ewen, B. and Loong, C.-K., J. Chem. Phys. 103, p. 2016 (1995).
5. Crawford, G.P. and Zumer, S., Liquid crystals in complex geometries, Taylor &; Francis, London, 1996).
6. Wu, X-ı., Goldburg, W.I., Liu, M.X., and Xue, J.Z., Phys. Rev. Lett., 69, 470, (1992).
7. Bellini, T., Clark, N.A., Schaefer, D.W., Phys. Rev. Lett., 74, 2740, (1995).
8. Aliev, F.M. and Nadtotchi, V.V. in: Disordered Materials and Interfaces, edited by Cummins, H.Z., Durian, D.J., Johnson, D.L., and Stanley, H.E., (Mater. Res. Soc. Proc, 407, Pittsburgh, PA, 1996), p. 125130.
9. Aliev, F.M. and Sinhain, G.P.: Electrically based Microstructural Characterization, edited by Gerhardt, R.A., Taylor, S.R., and Garboczi, E.J. (Mater. Res. Soc. Proc. 411, Pittsburgh, PA 1996), p. 413418.
10. Rozanski, S.R., Stanarius, R., Groothues, H., and Kremer, F.,, Liquid Crystals 20, p. 59 (1996).
11. Kreuzer, M. and Eidenschink, R. in Liquid crystals in complex geometries, edited by Crawford, G.P. and Zumer, S. (Taylor & Francis, London, 1996), p. 307324.
12. Phillips, J.C., Rep. Prog. Phys. 59, p. 1133 (1996).
13. Huse, D., Phys. Rev. B. 36, p. 5383 (1987).
14. Randieria, M., Sethna, J., and Palmer, R.G., Phys. Rev. Lett. 54, p. 1321 (1985).

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed