GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Monday, January 9, 2017

2:00 PM
in MRDC 3515

will be held the

DISSERTATION DEFENSE

for

Karthik Nayani

"Role of surface-like elastic constants in confined nematics"

Committee Members:

Dr. Mohan Srinivasarao, Advisor, MSE

Dr. Alberto Fernandez-Nieves, PHYS

Dr. Jung Ok Park, MSE

Dr. Anselm C. Griffin, MSE

Dr. Paul M. Goldbart, PHYS

Abstract:

Confined nematics are a natural setting to study aspects relating to phenomenology of symmetry breaking, evolution and dynamics of topological defects. In this study we highlight the interplay of the surface-like elastic constants with the phenomenology mentioned above. We exploit nematics confined to cylinders to study a spontaneous reflection symmetry breaking phase transition. The role of saddle-splay elasticity in driving this transition is described in detail. Further, we explore the dynamics of the novel defect configurations thus created. We uncover surprising aspects regarding the scaling of surface-like elastic constants by studying morphological transitions of spherical nematic droplets. We also confine nematics to rectangular geometries which reveal novel director and defect configurations. We exploit a monodomain- like configuration and the director arrangement in tactoids to shed light on the physics governing the nematic- biphasic transition of lyotropic chromonic liquid crystals. We also confine nematics to toroidal geometries with radial anchoring to delineate the coupling of geometry and topology with the director configuration. Finally, the role of differential polarizability is demonstrated in the accurate determination of order parameters of  liquid crystals.