The Investigation of Possible Candidates for a Calamitic and Discotic Mixture and the Physical Properties of the Eutectic Mixture N4

Joshua Scott Martin

A synthesis of the discotic liquid crystal 2,4,6- Tris[3,4- bis(decyloxy)phenyl-1-amino]-1,3,5- triazine was attempted. IR, NMR, DSC, and melting point data indicated that the synthesis was unsuccessful due to a failed attempt to reduce 3,4-di(dodecan-1-yloxy)-1-nitrobenzene. The calamitic liquid crytal n-hexyloxylbenzoic acide posed a few interesting experimental challenges that were solved to allow some exploration of this material. The nematic to crystal phase in this calamitic material was recorded to be on the order of a tenth of a second while the actual temperatures for the phase transitions matched those given in the literature. When an electric field was applied to the n-hexyloxybenzoic acid at high frequencies, the sample showed striking colors and some dynamic effects. At low frequencies the sample displayed electrohydrodynamic convection normally associated with negative dielectric material.

The splay and bend deformation constants were measured in the commercial mixture Nematic Phase 4 (N4). The bend deformation constant, K3, was measured to be (1.29±0.01) x 10-11 N at 25°C while only the ratio of the splay constant to magnetic anistropy, K1a could be found since χa is unknown for this mixture. K1a is shown to be temperature dependent and was not very repeatable for different cells. Electrohydrodynamic convection was also observed in N4 cells and Fast Fourier Transforms were performed. The patterns were also analyzed by taking line profiles of the pixels through the frames. The observed patterns are in rough agreement with other investigators.