자료유형  

 학위논문

Control Number  

0017161840

International Standard Book Number  

9798382811192

Dewey Decimal Classification Number  

530

Main Entry-Personal Name  

Randazzo, Katelyn S.

Publication, Distribution, etc. (Imprint  

[S.l.] : Princeton University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

286 p.

General Note  

Source: Dissertations Abstracts International, Volume: 85-12, Section: B.

General Note  

Advisor: Priestley, Rodney D.

Dissertation Note  

Thesis (Ph.D.)--Princeton University, 2024.

Summary, Etc.  

요약Incorporation of a second phase into a polymer system can be used to enhance local structure and properties, enabling useful technologies with applications in healthcare, energy, the environment, and myriad commodity products. In systems such as polymer nanocomposites and supported thin films, the large specific interfacial area can elicit significant deviations from bulk behavior of the overall polymer system. However, the ability to precisely anticipate and control polymer properties through incorporation of interfaces hinges upon a comprehensive understanding of the complex phenomena therein.One such phenomenon is polymer adsorption, wherein segments within a polymer chain physically adhere to an adjacent substrate. Polymer melts typically undergo adsorption in response to heating above the glass transition temperature Tg, corresponding to common processing conditions for polymer systems. Once regarded trivially as "dead," adsorbed layers are now recognized as capable of undergoing glass transitions and relaxations. However, the unknown details of their structure, properties, and evolution are an obstacle to control over glassy properties near interfaces.This dissertation details progress in elucidation of the structure-property-processing relationships within adsorbed polymer nanolayers. Building upon previous work investigating planar adsorbed layers of simple polymer systems, this work leverages a combination of new techniques for sample preparation and direct characterization of adsorbed layer structure and adsorbed layer Tg, which enables new insights into the influence of chemical and geometrical factors in governing interactions at an adsorbed interface.To ascertain the evolution of adsorbed layer structure and Tg at the polymer matrix-nanoparticle interface in polymer nanocomposites, we developed a model approach for isolating adsorbed layers from a polymer nanocomposite via Guiselin's experiment. Adsorbed layer structure and evolution were characterized by direct visualization via transmission electron microscopy (TEM) under cryogenic conditions, and the evolution of Tg was characterized via fluorescence spectroscopy. Analogous in-situ experiments wherein the nanoparticles with adsorbed layers were redispersed within a polymer matrix enabled a characterization of the factors influencing Tg characterization in polymer nanocomposites. Both adsorbed layer structure and Tg were found to co-evolve and to be annealing-time dependent.Follow-up work leveraged our model approach to ascertain the role of nanoparticle size and curvature on adsorbed layer structure. TEM imaging revealed that the structure of adsorbed layers was dependent upon nanoparticle size, with larger nanoparticles appearing to favor a greater degree of chain flattening.Finally, we investigated the role of interaction strength in the evolution of adsorbed layer Tg. Analogous polystyrene and poly(methyl methacrylate) planar adsorbed layers on silica-corresponding to weakly- and strongly-interacting pairings, respectively-were characterized via fluorescence spectroscopy and ellipsometry. Tg was found to co-evolve with structure in both polymers. Perhaps surprisingly, the adsorbed layer Tg was reduced from that of the bulk in both weakly- and strongly-interacting pairings, however the magnitude of deviation from bulk Tg varied with interaction strength.The findings presented herein are offered as a springboard for future work elucidating fundamental structure-property-processing relationships at interfaces featuring adsorption, which inform the design of useful materials.

Subject Added Entry-Topical Term  

Condensed matter physics.

Subject Added Entry-Topical Term  

Polymer chemistry.

Subject Added Entry-Topical Term  

Materials science.

Subject Added Entry-Topical Term  

Chemical engineering.

Index Term-Uncontrolled  

Polymer adsorption

Index Term-Uncontrolled  

Fluorescence

Index Term-Uncontrolled  

Glass transition

Index Term-Uncontrolled  

polymer system

Added Entry-Corporate Name  

Princeton University Chemical and Biological Engineering

Host Item Entry  

Dissertations Abstracts International. 85-12B.

Electronic Location and Access  

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Control Number  

joongbu:656816