"Pattern Formation in Nematic Liquid Crystal Mixtures Under Electrical and Magnetic Field Conditions"

ABSTRACT Liquid crystal mixtures under particular magnetic and or electric field conditions can produce patterns that can be seen and studied. In the first part of this study an eutectic mixture labeled ZLI-4330 was examined under electrohydrodynamic flow effects. Using purely a visual data acquisition method it was seen that the sample went through several patterns that were not only dependent on the voltage applied but also the frequency. A Voltage vs. Frequency graph was created showing where the thresholds for the stripes (or William's Domains), the area waves and the grid pattern are present in the sample. An in depth study of the patterns formed by different voltages at 65 Hz, 110 Hz and 155 Hz was also done. Light scattering was used on the 110 Hz patterns to acquire the scattering pattern. The second part of this study involved two non-eutectic mixtures of MBBA and 5-CB under combinations of magnetic and/or electric fields. The temporal and spatial FFTs were taken for both the non-eutectic mixtures and ZLI-4330. The temporal FFTS of these non-eutectic mixtures produced small artifacts in the graph that, as of yet, do not have a satisfactory explanation.

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