Searching for the ideal glass transition: Going to yotta seconds and beyond

Kong, Dejie; Meng, Yan; McKenna, Gregory B.

doi:10.1016/j.jnoncrysol.2023.122186

Cited by 8 publications

(12 citation statements)

References 67 publications

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“…This form can be qualitatively motivated by prior theoretical work where the barrier depends on density, which grows (or S 0 decreases) roughly linearly with cooling over a sufficiently narrow range in a polymer glass . Moreover, this functional form is identical to recent experimental measurements of the alpha time of vapor-deposited ultrastable polymeric glasses . Then, eq can be rewritten as with the effective prefactor that can be much shorter than τ 0 , depending on the strength of the temperature dependence of E* .…”

Section: Resultsmentioning

confidence: 78%

“…We note in Figure b that at the lowest investigated temperatures, the conductivity spectra signals the presence of an additional feature at frequencies between 10 1 and 10 3 Hz. This situation resembles that of other ionic conductors and is generated by the interference of secondary processes. ,, Interestingly, these relaxation features are faster than the conductivity relaxation (the latter itself being much faster than the alpha process) and hence differ from the Johari–Goldstein β-processes in the sense that they relate to the decoupled ionic motions.…”

Section: Resultsmentioning

confidence: 84%

“…This situation resembles that of other ionic conductors and is generated by the interference of secondary processes. 45,47,55 Interestingly, these relaxation features are faster than the conductivity relaxation (the latter itself being much faster than the alpha process) and hence differ from the Johari−Goldstein β-processes in the sense that they relate to the decoupled ionic motions.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…30 Moreover, this functional form is identical to recent experimental measurements of the alpha time of vapordeposited ultrastable polymeric glasses. 45 Then, eq 1 can be rewritten as…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Mechanisms Controlling the Energy Barrier for Ion Hopping in Polymer Electrolytes

et al. 2023

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The present work studies the mechanisms controlling the energy barrier for ion hopping in conducting polymers. Polymer electrolytes usually show Arrhenius-like temperature dependence of the conductivity relaxation time (characteristic time of local ion rearrangements) at temperatures below their glass transition T g . However, our analysis reveals that the Arrhenius fit of this regime leads to unphysically small prefactors, τ 0 ≪ 10 −13 s. Imposing a value of 10 −13 s for this parameter renders the fairly unexpected result that the energy barrier for charge transport in these polymers has strong temperature dependence even below T g . Our study also reveals significant temperature variations of the dielectric permittivity and the instantaneous shear modulus in the glassy state of these polymers. Using the Anderson and Stuart model, we demonstrate that these variations provide strong justifications for the temperature variation of energy barrier for ion hopping. Most importantly, the proposed approach reveals that the energy barrier controlling ion hopping in polymer electrolytes is significantly (∼30−40%) lower than that estimated using traditional Arrhenius fit. These new insights call for revisions of many earlier results based on apparent Arrhenius fits, and the newly proposed approach can provide more accurate guidance for the design of solid-state electrolytes with enhanced ionic conductivity.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 84%

Section: ■ Results and Discussionmentioning

confidence: 99%

“…30 Moreover, this functional form is identical to recent experimental measurements of the alpha time of vapordeposited ultrastable polymeric glasses. 45 Then, eq 1 can be rewritten as…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Mechanisms Controlling the Energy Barrier for Ion Hopping in Polymer Electrolytes

et al. 2023

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“…[32][33][34] Similar results were also observed for ultrastable Teflon glasses, where the dynamics measured using the nano-bubble inflation technique were found to be non-divergent in the deep glassy state. 11,13 In an attempt to use naturally-aged materials to explore dynamics in the deep glassy state, Mckenna and Coworkers 35,36 used millions of years of fossilized ambers, which were also found to exhibit less temperature dependent behavior compared to classic VFT (Vogel-Fulcher-Tammann) [20][21][22] behavior. Additionally, metallic glasses with less than 50 of relatively low fragility (see the ESI † for description of fragility (m) [37][38][39] ) have been reported to reach a deep glassy state after a few years of aging, exhibiting a reduction of 30-50 1C in T f .…”

Section: Introductionmentioning

confidence: 99%

Highly stable petroleum pitches provide access to the deep glassy state

Yoon,

Heinzman,

Smith

et al. 2023

Soft Matter

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AFM dilatometry measurements on ultra‐stable fluoropolymer glasses: Further evidence of extreme fictive temperature reduction

El Banna,

McKenna

2023

Journal of Polymer Science

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Ultra‐stable amorphous fluoropolymers glasses were created using vacuum pyrolysis deposition (VPD). Glass films with thickness ranging from 90 to 160 nm were grown at a substrate temperature of 0.86 Tg, where Tg is the glass transition temperature of the virgin polymer and is in units of K. Atomic force microscope (AFM) dilatometry measurements were conducted to investigate density behavior of the ultra‐stable glasses. Thickness measurements were made in stepwise fashion over a range of temperatures from ambient to above the Tg. Results show that the intersections of the line for the equilibrium liquid and those for the rejuvenated and stable glasses identifying the fictive temperature Tf result in Tf, rejuvenated = 347.3 K and Tf, stable = 269.5 K, that is, nearly 80 K below the Tg of the rejuvenated material and well below the notional Kauzmann temperature as estimated from the Vogel‐Fultcher‐Tammann (VFT) analysis of the cooling rate dependence of the calorimetric glass transition temperature reported previously. The results corroborate the published calorimetric results on the same ultra‐stable fluoropolymer glasses that witnessed Tf reductions of up to 62.6 K below the Tg of the rejuvenated system. In addition, to demonstrate the versatility of the AFM dilatometry methodology for the thin film response, isothermal de‐aging experiments were carried out to illustrate the devitrification kinetics. We also carried out one of the Kovacs’ signature key experiments, the asymmetry of approach, to further illustrate the method.

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Searching for the ideal glass transition: Going to yotta seconds and beyond

Cited by 8 publications

References 67 publications

Mechanisms Controlling the Energy Barrier for Ion Hopping in Polymer Electrolytes

Mechanisms Controlling the Energy Barrier for Ion Hopping in Polymer Electrolytes

Highly stable petroleum pitches provide access to the deep glassy state

AFM dilatometry measurements on ultra‐stable fluoropolymer glasses: Further evidence of extreme fictive temperature reduction

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