THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, June 28, 2016

11:00 AM
in MRDC 3515

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Graham Parkinson

"Advances in Physical Gel Structures "

Committee Members:

Prof. Paul Russo, Advisor, MSE

Prof. Karl Jacob, MSE

Prof. Mark Losego, MSE

Prof. Nicholas Hud, CHEM

Prof. Peter Yunker, PHYS

Abstract:

Gels are unlike any other state of matter. The presence of only a small amount of material can render a large volume of liquid immovable. Recently new classes of gel materials have emerged including aerogels and xerogels that may not deserve the name. New techniques in templating gels at both the molecular and macro levels allow for control of material properties and structure. In this work the classification of gels will address a fundamental question: when is a material a gel? The model system chosen is the hydrogel consisting of two-directional arborols. Arborols are a macromolecular class of materials named for their tree-like structure. First synthesized three decades ago, the materials have seen limited investigation from the perspective of a materials scientist. The formation of arborol gels will be investigated using a variety of scattering and microscopy methods to determine the necessary qualities for classifying this type of material transition. Differential dynamic microscopy will be used for the classification of a gel transition. It will mark the first study of a gel using this technique. The use of gels in the creation of novel materials is also proposed. The work will include the effect of other small molecules to arrest gel formation in the model system, or to tune it. The use of the gel to template liquid crystalline molecules will be tested to see if a LC phase can appear before the necessary critical concentration in a lyotropic LC system. Arborols will facilitate all these investigations. They constitute a superior system for study due to their small size and the simplicity of their hydrophobic-hydrophilic assembly mechanism.

The other parts of the work will look to build upon the scientific knowledge gained in the first part for engineering investigations of gels. Can a liquid template a solid gel? A ferrofluid has the potential to serve as a template for a solid gel. Ferrofluids, fluids with suspended magnetic particles, allow for a customized template as varying the strength and direction of a magnetic field produces a unique pattern within the material. The final proposed work is the creation of a new gel material, the aerocrystal, which will consist of a cross-linked polymeric aerogel. Aerogels are a novel class of materials where a liquid component has been replaced with a gas without the collapse of a former gel network. The formation of a crosslinked, aligned polypeptide polymer network with its liquid component removed will yield the first such material of its kind. This material will have a tunable chemistry as well as high surface area and porosity.