Physics of liquid crystals embedded in silica gels

Octylcyanobiphenyl (8CB) embedded in silica aerosil gels have been studied by means of high resolution X-ray scattering experiments. The silica particles form a hydrogen-bonded fractal gel network that introduces quenched disorder. As a result, the nematic to smectic-A transition is replaced by the growth of static short range smectic correlations. The X-ray scattering profile has two contributions: a thermal fluctuation term which resembles that of the pure liquid crystal and a static fluctuation term due to the random field that becomes important at low temperatures. The decrease of the smectic correlations with increasing silica density is consistent with theory and other experiments.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Park, Sungil, 1967-

Advisor dc:contributor.advisor

• Robert J. Birgeneau.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8275

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8275