GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Thursday, July 9, 2020

10:30 AM

via

BlueJeans Video Conferencing

https://bluejeans.com/636154853

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Hansol Lee

"Responsive Nanostructure Morphologies through Dynamic Assembly of Branched Functional Polymers"

Committee Members:

Prof. Vladimir V. Tsukruk, Advisor, MSE

Prof. Valeria Milam, MSE

Prof. Zhiqun Lin, MSE

Prof. Blair Brettmann, ChBE/MSE

Prof. Andrei Fedorov, ME

Abstract:

While polyelectrolytes (PEs) and poly(ionic liquid)s (PILs) are promising candidates for designing polymer nanostructures with diverse morphologies and functionalities, it is challenging to program the formation of complex morphologies with adaptive and switchable properties by using PEs and PILs with simplistic architecture. The proposed research addresses this issue by introducing variable macromolecular architecture, functionality, and environmental conditions into the assembly of PEs and PILs. The general hypothesis of the research is that branched macromolecular architecture with multiple functionalities can be exploited to mediate the organization of PEs and PILs and guide their assembly into pre-programmed complex morphologies with multifunctional responsive behavior.

The ultimate goal of the research is to understand and control the assembly of branched PEs and PILs and corresponding morphologies and properties. Accordingly, the first task aims to investigate the role of chain architecture and functional composition on the assembly, interfacial behavior, and resulting morphologies of branched polyelectrolytes and poly(ionic liquid)s. In the second task, we will unravel the role of environmental parameters, such as solvents and substrates on the assembly of branched PEs and PILs to develop truly dynamic nanostructures. We will use ionic liquids as solvents and ionogels as dynamic substrates. The conformations, microstructure and morphology of branched PEs and PILs will be evaluated in conjunction to physical properties including mechanical and ion transport properties. Finally, using the mechanisms of organization of branched PEs and PILs studied in previous tasks, functional PE nanocomposites with nanocellulose will be developed in forms of ionogels with remarkable mechanical and ion dynamic properties.

This work will inspire the design of polymer nanostructures with pre-programmed complex morphologies with multifunctional responsive behavior. This work will help to establish a systematic, transformative understanding, and construction of component-structure-property relationships for the branched PEs and PILs. The development of functional PE and PIL nanocomposites with enhanced mechanical performance and conductivity close to that of pure ionic liquids will meet the challenging requirements of materials in energy storage and conversion applications.