All ETDs from UAB

Advisory Committee Chair

Eugenia Kharlampieva

Advisory Committee Members

Shane A Catledge

Vinoy Thomas

Sadanandan Velu

Sergey Vyazovkin

Document Type

Dissertation

Date of Award

2023

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Polymer thin films possess unique properties, cost-effectiveness, and flexibility, making them vital for enhancing surface functionality. Layer-by-layer (LbL) assembly allows for synthesis of ultrathin polymeric films with precise control over film thickness, material selection, surface chemistry, and responsiveness. Current advancements in LbL assembly focus on understanding film formation and deposition conditions on film’s structure and properties. Covalent cross-linking of physically bonded LbL networks forms multilayer hydrogel networks capable of absorbing large amounts of water. The use of stimuli-responsive polymers has facilitated the advancement of "smart" materials capable of responding to external stimuli. Stimuli-responsive hydrogels exhibit reversible volume changes, making them valuable in biosensing and controlled therapeutic delivery. Thus, this dissertation explores pH-sensitive ultrathin hydrogen-bonded coatings and hydrogel films, investigating the influence of network structure on film properties. Chapter 1 of the dissertation provides an introductory overview of stimuli-responsive polymers and hydrogels, emphasizing the significance of the relationship between structure and the properties of hydrogels. Chapter 2 focuses on the growth of hydrogen-bonded poly(methacrylic acid)/poly(N-vinylpyrrolidone) (PMAA/PVPON) multilayers using atomic force microscopy and examines the impact of shaking during film assembly on chain diffusion, polymer adsorption, and film properties. Chapter 2 examines iii the impact of molecular chain rearrangements on the roughness and thickness of planar membranes or multilayer capsule shells following the removal of the substrate. In Chapter 3, the synthesis of free-standing ultrathin hydrogen-bonded (PMAA/PVPON) films and (PMAA) hydrogels is discussed. The effects of the release method on film properties are investigated, and the influence of Zr(IV) ionic species on the mechanical properties and swelling of hydrogels is explored. The chapter highlights the control of thin film properties through pH-triggered hydration and the incorporation of ionic species. Chapter 4 presents a two-module research project utilizing an alginate gel platform to study hydrogel structure-property relationships. Students investigate the impact of synthesis conditions on gel bead size and analyze the effects of gel size and solution environment on dye encapsulation and release. The experiment provides a comprehensive learning experience, integrating concepts from general chemistry, polymer science, and material science. Chapter 5 concludes by discussing the potential applications of pH-responsive LbL hydrogel coatings in sensing and drug delivery, highlighting their significance, versatility, and future research directions. Overall, this dissertation contributes to our understanding of polymer thin hydrogen-bonded films and hydrogels, offering insights into their synthesis, properties, and applications across various fields of research.

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