자료유형  

 학위논문

Control Number  

0017163323

International Standard Book Number  

9798383581872

Dewey Decimal Classification Number  

540

Main Entry-Personal Name  

Tracy, Megan.

Publication, Distribution, etc. (Imprint  

[S.l.] : The University of Wisconsin - Madison., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

174 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-02, Section: B.

General Note  

Advisor: Ediger, Mark D.

Dissertation Note  

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2024.

Summary, Etc.  

요약Stable vapor-deposited glasses are a unique set of materials, achieving packing arrangements that would conservatively take thousands of years to form within hours by making use of the enhanced mobility of molecules at the free surface during the deposition process. One feature of these unusual disordered materials is the nature of their return to equilibrium upon heating. Specifically, when heated above Tg, they typically transform back to the supercooled liquid more slowly than their liquid-cooled counterparts, and through combinations of surface front and bulk nucleation and growth mechanisms that are more comparable to crystal melting mechanisms.This work sought to examine the process of returning to equilibrium while the glass remains at temperatures below Tg, revealing unusual features in the start of this very slow rejuvenation process. While the slow start of this rejuvenation was observed for less stable glass (and even to completion for the least stable glasses), an unusual partial rejuvenation was observed for the most stable samples. This phenomenon was qualitatively distinct from any previously observed rejuvenation mechanism in stable glasses, and is attributed to a partial recovery of fast relaxation processes at high frequencies, outside the spectral window available in this study. In contrast, however, no such additional rejuvenation was observed in complementary simulations on well-equilibrated swap Monte Carlo glasses; we discuss some reasons for this possible disagreement between experiment and simulation.Separate work has focused on stable vapor-deposited glasses consisting of more than one component. These co-deposited glasses are much less well-studied than their single-component cousins, despite their high technological relevance in many organic electronic applications. This work found that a pair of glass-forming molecules with Tg values that differ by ~50% were able to form stable glasses at temperatures below the mixture's Tg, suggesting that the molecules at the free surface enjoy an averaged mobility between that of the two different species on their own during deposition. Additionally, the transformation mechanisms of these co-deposited films were observed to be the same as those seen in single-component samples. Finally, the rate of mixing between a liquid of one material and glasses of different stabilities of the other, and comparisons are made with the case where both liquid and glass are of the same material.

Subject Added Entry-Topical Term  

Chemistry.

Subject Added Entry-Topical Term  

Physical chemistry.

Subject Added Entry-Topical Term  

Materials science.

Subject Added Entry-Topical Term  

Analytical chemistry.

Index Term-Uncontrolled  

Co-deposited glasses

Index Term-Uncontrolled  

Molecular glasses

Index Term-Uncontrolled  

Physical vapor deposition

Index Term-Uncontrolled  

Rejuvenation

Index Term-Uncontrolled  

Ultrastable glasses

Added Entry-Corporate Name  

The University of Wisconsin - Madison Chemistry

Host Item Entry  

Dissertations Abstracts International. 86-02B.

Electronic Location and Access  

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Control Number  

joongbu:656220