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Author ORCID Identifier

https://orcid.org/0000-0003-1583-7834

AccessType

Campus-Only Access for Five (5) Years

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2021

Month Degree Awarded

May

First Advisor

James J. Watkins

Second Advisor

Samuel P. Gido

Subject Categories

Polymer Chemistry

Abstract

Blends of Poly(styrene)-b-poly(ethylene oxide) and poly(butadiene)-b-poly(acrylic acid) were prepared and the resulting morphology examined. Both macrophase and microphase separated morphologies were observed, depending on the ratio of the diblock copolymers within the blend. A microphase separated lamellar morphology was obtained via hydrogen-bond driven self-assembly for some blend compositions. Small-angle x-ray scattering helped determine the morphology while transmission electron microscopy, coupled with differential staining, confirmed the morphology. The lamellar morphology was revealed to be a four-layer pattern with a combined poly(ethylene oxide)/poly(acrylic acid) layer appearing twice.

Blends of block copolymers containing a hydrogen bond accepting block and nanoparticles (or nanoparticle-like materials) functionalized with hydrogen bond donating ligands were explored to determine whether a well-ordered morphology with high particle loadings could be achieved. Polyhedral oligomeric silsesquioxane, functionalized with maleic acid or phenyl amine, was blended into disordered Pluronic® block copolymers to induce ordered morphologies. These blends achieved well-ordered morphologies and order-to-order morphological transitions at particle loadings up to 70 w/w%. Furthermore, blends with high particle concentrations did not macrophase separate and were exposed to elevated temperatures which formed mesoporous silica structures via calcination reaction. Gold nanoparticles functionalized with hydrogen-bond donating ligands were blended with different block copolymers with hydrogen bond accepting blocks. Well-ordered morphologies with relatively high particle loadings were achieved. The morphology was determined with a combination of small-angle x-ray scattering and transmission electron microscopy.

Cross-linked polyethylene glycol diacrylate and plastic type electrolytes were investigated as polymer gel electrolytes for lithium-ion batteries. Succinonitrile was the electrolyte within a cross-linked matrix that was systematically studied to achieve high conductivities over a wide range of temperatures. Mixtures of ethylene carbonate and succinonitrile helped improve conductivities. The molecular weight of polyethylene glycol diacrylate was varied and the cross-link density controlled by UV exposure time, which provided an opportunity to further optimize the electrolyte. The conductivities of the polymer gel electrolytes were determined by electrochemical impedance spectroscopy and mechanical properties were measured by dynamical mechanical analysis.

DOI

https://doi.org/10.7275/22474483.0

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