Bent-Core Liquid Crystals: Pattern Formation and Phase Transitions

In recent years bent-core (BC)liquid crystals have begun to mature into a relevantsubfield ofresearch. The shape and symmetry of BC molecules offers awealth of new questions not presented by calamiticliquid crystals,many of which have yet to be addressed. In this work,I use magneticfield induced birefringence, dynamic lightscattering, and densitymeasurements to provide evidence of a transitionbetween two opticallyisotropic phases in two BC liquid crystals, and toshow that this transition can be understood inthe framework of the theoretically predicted, butpreviouslyunobserved tetrahedratic - isotropic transition. Also, four distinct, frequency dependent, regions ofelectrohydrodynamic convection (EHC) werecharacterized in a BC liquid crystal, which showedtwo frequency dependent changes in thesign of the electrical conductivity anisotropy. Thiswork looks into some exciting behaviors in novel BCliquid crystal materials and should be of interestthose involved with EHC or BC liquid crystals.

David B. Wiant,Ph.D: Studied physics at Kent State University. Iam currently a postdoctoral fellow at Wake Forest UniversityMedical School.