Skip to main content Accessibility help
×
Home

Dielectric and Mechanical Relaxation of Glass-Forming Liquids in Nanopores

  • H. Wendt (a1) and R. Richert (a1)

Abstract

We have measured the time resolved phosphorescence of different probe molecules in glassforming solvents under the condition of geometrical confinement in porous glasses. This solvation dynamics technique probes the local dielectric relaxation in the case of a dipolar chromophore in polar liquids. In the absence of dipolar interactions, the observed Stokes shifts reflect the local density or mechanical responses. Therefore, both orientational and translational modes of molecular motions can be measured for liquids imbibed in porous silica glasses. The effect of confinement on the relaxations of supercooled liquids is strongly dependent on the surface chemistry and can be rationalized on the basis of the cooperativity concept. As in the bulk case, we find that the relaxations in nano-confined liquids display heterogeneous dynamics. The density relaxation turns out to be more sensitive to the thermal history relative to the orientational features of molecular motion. By selectively positioning the chromophores at the liquid/solid interface, we observe also that the structural relaxation of the liquid in the immediate vicinity of the glass surface is slowed down but not entirely blocked.

Copyright

References

Hide All
1. Dynamics in Small Confining Systems III, edited by Drake, J.M., Klafter, J. and Kopelman, R. (Mater. Res. Soc. Proc. 464, Pittsburgh, PA, 1997).
2. Molecular Dynamics in Restricted Geometries, edited by Klafter, J. and Drake, J.M. (John Wiley, New York, 1989).
3. Jackson, C.L. and McKenna, G.B., J. Non-Cryst. Solids 131–133, 221 (1991).
4. Petychakis, L., Floudas, G. and Fleischer, G., Europhys. Lett. 40, 685 (1997).
5. Richert, R., Phys. Rev. B 54, 15762 (1996).
6. Adam, G. and Gibbs, J.H., J. Chem. Phys. 43, 139 (1965).
7. Zhou, H.-X., Bagchi, B., Papazyan, A. and Maroncelli, M., J. Chem. Phys. 97, 9311 (1992).
8. Richert, R., Stickel, F., Fee, R.S. and Maroncelli, M., Chem. Phys. Lett. 229, 302 (1994).
9. R. Richert in Disorder Effects on Relaxational Processes, edited by Richert, R. and Blumen, A. (Springer-Verlag, Berlin, 1994).
10. Schwalb, G., Deeg, F.W. and Bräuchle, C., J. Non-Cryst. Solids 172–174, 348 (1994).
11. Farrer, R.A., Loughnane, B.J. and Fourkas, J. T., J. Phys. Chem. 101, 4005 (1997).
12. C. Streck, Melnichenko, Y.B. and Richert, R., Phys. Rev. B 53, 5341 (1996).
13. Yan, X., Streck, C. and Richert, R., Mat. Res. Soc. Symp. Proc. 464, 33 (1997).
14. Richert, R., J. Phys.: Condens. Matter 8, 6185 (1996).
15. Fourkas, J.T., Benigno, A. and Berg, M., J. Non-Cryst. Solids 172–174, 234 (1994).
16. Berg, M., J. Phys. Chem. A 102, 17 (1998).
17. Wendt, H. and Richert, R., J. Phys. Chem. A 102, 5775 (1998).
18. Richert, R. and Wagener, A., J. Phys. Chem. 95, 10115 (1991).
19. Wendt, H. and Richert, R., J. Phys.: Condens. Matter (in press).
20. Williams, G. and Watts, D.C., Trans. Faraday Soc. 66, 80 (1970).
21. Donati, C. and Jackie, J., J. Phys.: Condens. Matter 8, 2733 (1996).
22. Reichardt, C., Solvents and Solvent Effects in Organic Chemistry (VCH, Weinheim, 1988).
23. Richert, R. and Wagener, A., J. Phys. Chem. 97, 3146 (1993).
24. Ediger, M.D., Angell, C.A. and Nagel, S.R., J. Phys. Chem. 100, 13200 (1996).
25. Schmidt-Rohr, K. and Spiess, H.W., Phys. Rev. Lett. 66, 3020 (1991).
26. Böhmer, R., Chamberlin, R.V., Diezemann, G., Geil, B., Heuer, A., Hinze, G., Kuebler, S.C., Richert, R., Schiener, B., Sillescu, H., Spiess, H.W., Tracht, U., Wilhelm, M., J. Non-Cryst. Solids 235–237, 1 (1998).
27. Richert, R., J. Phys. Chem. B 101, 6323 (1997).
28. Richert, R., J. Non-Cryst. Solids 235–237, 41 (1998).
29. Richert, R. and Richert, M., Phys. Rev. E 58, 779 (1998).
30. Stephens, M.D., Saven, J.G. and Skinner, J.L., J. Chem. Phys. 106, 2129 (1997)

Dielectric and Mechanical Relaxation of Glass-Forming Liquids in Nanopores

  • H. Wendt (a1) and R. Richert (a1)

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