Experimental investigations of the pretransition behavior near the nematic-smectic A phase transition

We present here two experiments which measure the static and dynamic pretransition behavior of the nematic-smectic A phase transition of the liquid crystal CBOOA. The first experiment is a conventional Rayleigh light scattering measurement performed with excellent temperature control of the liquid crystal. The second is a novel magneto-optic experiment which uses an external magnetic field to distort the liquid crystal and a sensitive optical interference technique to measure the distortion. Both measurements are performed with millikelvin temperature resolution and yield critical exponents for the elastic constants and the twist viscosity coefficient. These results are inconsistent with the three proposed theories of the critical behavior at least in the simple form in which the theories were first proposed and suggest that further theoretical work is necessary in order to understand this phase transition. A theory of the nonlinear elastic response of liquid crystals near the nematic-smectic A phase transition is also presented.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Chu, Kung-Chao

Contributors dc:contributor

• McMillan, W.L.

• pretransition behavior
• nematic-smectic A phase transition
• liquid crystal CBOOA

Statement dc:rights

• 1977 Kung-Chao Chu

Language dc:language

en

Identifier

252915

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25614