The dynamics of field-induced director reorientation for a nematic phase comprised of flexible molecules
| Autor: | G. Kothe, Geoffrey R. Luckhurst, M. Tittelbach, J. W. Emsley, E. Ciampi, Bakir A. Timimi |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | The Journal of Chemical Physics. 107:5907-5913 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | The effect of rotating the nematic phase of 4-n-pentyl-4′-cyanobiphenyl (5CB) at a frequency ωr about an axis perpendicular to an applied magnetic field has been studied using deuterium NMR spectroscopy. The alignment of the directors produced by the competing magnetic and rotational torques was monitored by the effect produced on Δνi, the deuterium quadrupolar splittings at all five alkyl chain and one biphenyl core sites in 5CB. The director orientation was found to be independent of the site monitored. The change in the director orientation produced by stopping the rotation of a sample was followed by recording deuterium spectra during the reorientation process. The ratios of the quadrupolar splittings, Δνi(t)/Δνi(t=0), are found to be site independent, which shows that measuring the director reorientation rates by this method will produce the same result independently of which molecular site is monitored. This contrasts with recent reports of experiments which found that monitoring director reorientat... |
| Databáze: | OpenAIRE |
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