1. Liquid Crystal Properties of Aggregated Dyes
Viva Horowitz

2. Purpose Investigating a liquid crystal phase of an aggregated dye
Very little work has been done so far, according to the literature
e.g. measure birefringence as a function of temperature
Birefringence ∆n is a measure of the difference in the index of refraction for light polarized along one direction, compared to another direction

3. Liquid Crystals A liquid crystal is a fluid with orientational order.
An isotropic liquid has no orientational order.
A nematic liquid crystal’s molecules do not have positional order
Order Parameter
S = (3/2) cos2 q - 1/2

4. Sunset Yellow FCF Nematic phase Orange-red powder
Used as a food coloring
Chemical diagram from
Uses:

5. Absorption Spectrum of Monomer

6. Procedure for Mapping Phase Diagram
Mix solutions
Make sealed cell with sample
Cell is placed on heating stage on microscope, between crossed polarizers
The cell is slowly heated, and temperatures are recorded
Goal: Phase Diagram

8. Current Work Upcoming: Order parameter measurements
Birefringence measurements
Upcoming: Order parameter measurements