| Autor: |
Lukaschek, Michail, Kothe, Gerd, Schmidt, Claudia, Gomes, Alexandre E., Polimeno, Antonino |
| Předmět: |
|
| Zdroj: |
Journal of Chemical Physics; 9/1/2002, Vol. 117 Issue 9, p4550, 7p, 4 Diagrams, 1 Chart, 3 Graphs |
| Abstrakt: |
The viscoelastic behavior of a nematic dimer is studied by deuteron ([sup 2]H) nuclear magnetic resonance (NMR) spectroscopy using a cone-and-plate rheometer. From the [sup 2]H NMR spectra, monitored as a function of the shear rate, the orientation of the director relative to the magnetic field is obtained. Analysis of this experiment, using an analytical and a numerical solution of the LeslieEricksen equations, gives detailed information on the viscoelastic properties of the dimer. In particular, the two Leslie viscosities α[sub 2] and α[sub 3] and the three-dimensional director distribution are determined. The analysis reveals that α[sub 2] and α[sub 3] are both positive, that is, the dimer is of the flow-aligning type, and the director is tilted by an angle of about 33° from the magnetic field toward the velocity axis. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
