Analysis of an Unusual Liquid Crystal Phase Transition

Liquid crystals are a unique phase of matter that resemble a state between a solid and liquid. Within these properties, liquid crystal molecules have the ability to align and create layers. From this phenomenon, many electro-optical effects can be investigated, such as measuring the tilt angle between molecules at different temperatures and applied electric fields and also measuring the birefringence, which is a unique property of liquid crystals in which the index of refraction of the sample behaves differently along different axes. In order to better understand these electro-optical effects, we designed a more precise protocol of measuring this data. This procedure includes manipulating polarizing filters and measuring the effective light intensities with a camera attached to the microscope. From this, we can more successfully analyze the electroclinic effects of liquid crystal displays. For instance, we analyzed the phase transition of two unusual ``de Vries'' smectic liquid crystals. The phase transition for both materials was consistent with mean field theory near a tricritical phase transition.