Concepts and applications of rigidity in non-crystalline solids: a review on new developments and directions

Micoulaut, Matthieu

doi:10.1080/23746149.2016.1161498

Cited by 28 publications

(48 citation statements)

References 137 publications

(236 reference statements)

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“…Thus Z nc only counts repulsively interacting particles (those with r ij ≡ | r j − r i | < 1) as being in contact, as is appropriate for thermal systems. [21] Flexible chains crystallize into a random-walk closepacked (RWCP) structure wherein monomers closepack but chains retain random-walk-like structure and are isotropically oriented. [15] Semiflexible chains form Table I).…”

Section: Model and Methodsmentioning

confidence: 99%

“…1 and 2 may apply. [21] If isostaticity controls solidification but angular degrees of freedom are gradually frozen out as chain stiffness increases, the average number of noncovalent contacts per monomer at the solidifcation temperature T s , Z nc (T s ) , should vary smoothly from Z iso nc f lex to Z iso nc stif f . Below, we use molecular dynamics simulations to show that this indeed occurs in model systems, and derive a generalized isostaticity criterion describing the phenomenon.…”

Section: Introductionmentioning

confidence: 99%

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Isostaticity and the solidification of semiflexible polymer melts

2017

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Using molecular dynamics simulations of a tangent-soft-sphere bead-spring polymer model, we examine the degree to which semiflexible polymer melts solidify at isostaticity. Flexible and stiff chains crystallize when they are isostatic as defined by appropriate degree-of-freedom-counting arguments. Semiflexible chains also solidify when isostatic if a generalized isostaticity criterion that accounts for the slow freezing out of configurational freedom as chain stiffness increases is employed. The dependence of the average coordination number at solidification Z(Ts) on chains' characteristic ratio C∞ has the same functional form [Z a − b ln(C∞)] as the dependence of the average coordination number at jamming Z(φJ ) on C∞ in athermal systems, suggesting that jamming-related phenomena play a significant role in thermal polymer solidification.

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Section: Model and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Isostaticity and the solidification of semiflexible polymer melts

2017

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“…4 For the equilibrium viscosity, we employ the Mauro-Yue-Ellison-Gupta-Allan (MYEGA) equation 30 derived from topological constraint theory, [25][26][27][28][29] log 10 g eq ðT f Þ ¼ log 10 g 1 þ ð12 À log 10 g 1 Þ 4 For the equilibrium viscosity, we employ the Mauro-Yue-Ellison-Gupta-Allan (MYEGA) equation 30 derived from topological constraint theory, [25][26][27][28][29] log 10 g eq ðT f Þ ¼ log 10 g 1 þ ð12 À log 10 g 1 Þ…”

Section: Model Derivationmentioning

confidence: 99%

“…Assuming isobaric conditions, the kinetics of the glass relaxation depend on 3 factors: chemical composition, temperature, and thermal history. In this paper, based on energy landscape [21][22][23][24] and temperaturedependent constraint theories, [25][26][27][28][29] we derive a new model to quantitatively predict the composition dependence of nonequilibrium viscosity of glass. For example, the dynamics of 2 glasses of the same composition and at the same temperature can vary by many orders of magnitude depending on the details of thermal history.…”

Section: Introductionmentioning

confidence: 99%

“…While the model presented therein provided an accurate description of Corning EAGLE XG â glass viscosity over the full range of measured temperatures and fictive temperatures, it does not enable prediction of the composition dependence of glass viscosity. In this paper, based on energy landscape [21][22][23][24] and temperaturedependent constraint theories, [25][26][27][28][29] we derive a new model to quantitatively predict the composition dependence of nonequilibrium viscosity of glass. The model is validated against several alkali and alkaline earth aluminosilicate commercial glasses using a custom-designed beam bending viscometer that allows viscosities up to 10 16 PaÁs to be directly measured.…”

Section: Introductionmentioning

confidence: 99%

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Predictive model for the composition dependence of glassy dynamics

et al. 2017

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The problem of glass relaxation is traditionally known as one of the most challenging problems in condensed matter physics, with important implications for several high‐tech applications of glass. In this study, we present a predictive model for the temperature, thermal history, and composition dependence of glassy relaxation dynamics. Our model enables, for the first time, the quantitative prediction of relaxation behavior for new glass compositions. Using the commercial Corning EAGLE XG® alkaline earth aluminosilicate glass as a reference, the model gives accurate predictions of the nonequilibrium viscosity for 4 other aluminosilicate glasses, covering both alkali‐free and alkali‐containing compositions, without any free fitting parameters. Using the composition‐dependent nonequilibrium viscosity model, only the measured values of the glass transition temperature and fragility are required to predict the nonequilibrium viscosity as a function of both temperature and thermal history. The range of glass transition temperatures of the 4 verification glasses covers about 200°C, while that of fragility values is about 6. As such, this work gives insights into the structural origin of nonequilibrium viscosity and can enable the future design of glass compositions with tailored relaxation behavior.

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Tetrahedral Complexity in Amorphous Networks: A Possible Clue for the Unique Properties of Phase‐Change Materials

Micoulaut

Flores‐Ruiz

Pradel

et al. 2020

Physica Rapid Research Ltrs

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A typical binary amorphous telluride GeTe2 is investigated from first‐principles molecular dynamics simulations. After a comparison with chemical analogs from neutron or X‐ray diffraction experiments, such as GeO2 or GeSe2, the structure of this material is studied by examining real and reciprocal space properties. It is found that the base geometrical motifs of the germanium atom can be either in tetrahedral or in defected coordinations involving pyramidal units. A review of previous results for other compositions reveals that such binary Ge tellurides contain soft tetrahedra, at variance with lighter chalcogenides, such as GeS and GeSe, and are characterized by an increased angular bending motion (typically 20°) as compared with, e.g., GeS (5°). In addition, for amorphous Ge‐rich materials, GeTe2 and GeTe, a secondary tetrahedral geometry appears, related to the presence of GeGe bonds, having a larger mean angle of about 125°. These typical features not only relate to characteristics observed from scattering experiments but may also be a crucial feature for the understanding of the phase‐change phenomena.

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Concepts and applications of rigidity in non-crystalline solids: a review on new developments and directions

Cited by 28 publications

References 137 publications

Isostaticity and the solidification of semiflexible polymer melts

Isostaticity and the solidification of semiflexible polymer melts

Predictive model for the composition dependence of glassy dynamics

Tetrahedral Complexity in Amorphous Networks: A Possible Clue for the Unique Properties of Phase‐Change Materials

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