Date of Award

2000

Document Type

Restricted Thesis

Terms of Use

© 2000 Jacob J. Krich. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Physics & Astronomy Department

First Advisor

Peter J. Collings

Abstract

Experiments performed on the nematic liquid crystal 5CB successfully measured the correlation length of its pretransitional fluctuations as a function of temperature. These correlation lengths were shown to decay according to the predictions of Landau-de Gennes theory. A correction for double scattering in the experiment was derived and used in the analysis. The bare correlation length of 5CB was found to be 3.9 ± 0.3 Å, which is approximately a molecular width. Similar experiments performed on the chiral nematic liquid crystal CE6 found the chirality of its isotropic fluctuations to be 16.5 ± 0.3 µm¹, which is only slightly more than its chirality in the chiral nematic phase (14.0 ± 0.7 µm¹). This finding contradicts the prediction of a modified Landau-de Gennes theory that the chirality in the isotropic phase should be 22.4 ± 0.1 µm¹.

Comments

The research in this thesis is related to the following article: "Helix inversion in the chiral nematic and isotropic phases of a liquid crystal."

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