Date of Award

Spring 5-2016

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

Committee Chair

Dr. Sarah E. Morgan

Committee Chair Department

Polymers and High Performance Materials

Committee Member 2

Dr. Robert Y. Lochhead

Committee Member 2 Department

Polymers and High Performance Materials

Committee Member 3

Dr. Sergei I. Nazarenko

Committee Member 3 Department

Polymers and High Performance Materials

Committee Member 4

Dr. Derek L. Patton

Committee Member 4 Department

Polymers and High Performance Materials

Committee Member 5

Dr. Jeffrey S. Wiggins

Committee Member 5 Department

Polymers and High Performance Materials

Abstract

The study of a class of materials almost always begins with the development of an understanding of properties in the bulk state. However, it is the study of surface critical phenomena that has led to a number of new important insights into polymer behavior. A systematic understanding of physical properties in the immediate vicinity of surface and interfacial layers, which cannot be deduced by simple extrapolation of bulk properties, is of significant importance for advancements in polymer applications where the interface drives performance, such as in membranes, coatings, drug-delivery systems, medical devices, and composites.

First, the surface and interfacial modification and characterization of sulfone polymers will be described (Part I). Much of what exists in molecular modeling and experimental literature explains the behavior of flexible or modified chains. There is still a lack of accepted models that adequately explain chain conformation, structural organization, and dynamics of semi-rigid and rigid rod polymers at surfaces and interfaces. The purpose of this research was to investigate the environmental and structural parameters that determine polymer chain conformation, organization, and dynamics at the polymer-air interface for a series of semi-rigid and rigid rod sulfone polymers cast from solution. Refined models of polysulfones (and by extension semi-rigid/rigid rod polymers) behavior at surfaces and interfaces were developed through combined experimental and simulation analysis.

The second section of this work (Part II) will discuss the nanophase manipulation of polyisobutylene (PIB) based thermoplastic elastomers (TPE’s) and polyhedral oligomeric silsesquioxane (POSS) nanocomposites. The phase behavior and permeability of (PS-PIB)2-s-PAA miktoarm star terpolymers with varying volume fractions of PAA was investigated for potential applications as permselective TPE’s. Results of this work present the potential for design of novel microstructures for specific applications through precise control of architecture, composition, and interaction parameters of the components. Lastly, the rheological properties and crystallization kinetics of POSS filled polyphenylenesulfide (PPS) and polyetheretherketone (PEEK) nanocomposites were studied. The findings indicate the potential for improvements in melt viscosity and crystallization of high temperature thermoplastics with tailored POSS/polymer interactions.

ORCID ID

orcid.org/0000-0002-0125-7532

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