Date of Award

Spring 2005

Document Type

Restricted Thesis

Terms of Use

© 2005 Viva R. Horowitz. 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


Physics & Astronomy Department

First Advisor

Peter J. Collings


The nematic liquid crystal phase is a phase of matter in which the particles have a preferred orientational direction, as opposed to the liquid phase, with no preferred direction, and the solid crystal phase, with an ordered lattice structure. In an aggregated dye, or chromonic, liquid crystal, molecules come together in aggregates, and these aggregates form a liquid crystal. Aggregated dyes that form liquid crystals have been known for some time, but few fundamental measurements have been taken prior to this research. Unlike most liquid crystals, aggregated dye liquid crystals are water-soluble, opening the door to applications of liquid crystals in the fields of biology and medicine. In order to move ahead with explorations of applications and general understanding of chromonic liquid crystals, more must be known about the properties of this phase; thus, this research focuses on one aggregated dye liquid crystal, aqueous Sunset Yellow FCF. Phase diagram measurements, birefringence measurements, and order parameter measurements were obtained for aqueous Sunset Yellow. A general model of the aggregation consistent with both the results of the birefringence measurements and the results of the order parameter measurements is suggested in which the nitrogen-nitrogen double bonds of the Sunset Yellow molecule are perpendicular to the long axis of the aggregate.