Accueil >
Production scientifique
Dynamique et rhéologie des fluides complexes (gels, polymères, mousses, colloïdes)
(36) Production(s) de l'année 2019
|
|
Configurational entropy of glass-forming liquids
Auteur(s): Berthier L., Ozawa M., Scalliet C.
(Article) Publié:
The Journal Of Chemical Physics, vol. 150 p.160902 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02123889_v1
Ref Arxiv: 1902.07679
DOI: 10.1063/1.5091961
WoS: WOS:000466698700002
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
13 Citations
Résumé: The configurational entropy is one of the most important thermodynamic quantities characterizing supercooled liquids approaching the glass transition. Despite decades of experimental, theoretical, and computational investigation, a widely accepted definition of the configurational entropy is missing, its quantitative characterization remains fraud with difficulties, misconceptions and paradoxes, and its physical relevance is vividly debated. Motivated by recent computational progress, we offer a pedagogical perspective on the configurational entropy in glass-forming liquids. We first explain why the configurational entropy has become a key quantity to describe glassy materials, from early empirical observations to modern theoretical treatments. We explain why practical measurements necessarily require approximations that make its physical interpretation delicate. We then demonstrate that computer simulations have become an invaluable tool to obtain precise, non-ambiguous, and experimentally-relevant measurements of the configurational entropy. We describe a panel of available computational tools, offering for each method a critical discussion. This perspective should be useful to both experimentalists and theoreticians interested in glassy materials and complex systems.
Commentaires: 20 pages, 11 figures, submitted to the Journal of Chemical Physics. Réf Journal: J. Chem. Phys. 150, 160902 (2019)
|
|
|
New interaction potentials for alkali and alkaline-earth aluminosilicate glasses
Auteur(s): Sundararaman Siddharth, Huang Liping, Ispas S., Kob W.
(Article) Publié:
The Journal Of Chemical Physics, vol. 150 p.154505 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02121330_v1
DOI: 10.1063/1.5079663
WoS: 000465442100042
Exporter : BibTex | endNote
7 Citations
Résumé: We apply a recently developed optimization scheme to obtain effective potentials for alkali andalkaline-earth aluminosilicate glasses that contains lithium, sodium, potassium, or calcium asmodifiers. As input data for the optimization, we used the radial distribution functions of theliquid at high temperature generated by means of ab initio molecular dynamics simulations anddensity and elastic modulus of glass at room temperature from experiments. The new interactionpotentials are able to reproduce reliably the structure and various mechanical and vibrationalproperties over a wide range of compositions for binary silicates. We have tested these potentialsfor various ternary systems and find that they are transferable and can be mixed, thus allowing toreproduce and predict the structure and properties of multi-component glasses.
|
|
|
Zero-temperature glass transition in two dimensions
Auteur(s): Berthier L., Charbonneau Patrick, Ninarello A. S., Ozawa M., Yaida Sho
(Article) Publié:
Nature Communications, vol. 10 p.1508 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02101358_v1
Ref Arxiv: 1805.09035
DOI: 10.1038/s41467-019-09512-3
WoS: 000463170600007
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
16 Citations
Résumé: The nature of the glass transition is theoretically understood in the mean-field limit of infinite spatial dimensions, but the problem remains totally open in physical dimensions. Nontrivial finite-dimensional fluctuations are hard to control analytically, and experiments fail to provide conclusive evidence regarding the nature of the glass transition. Here, we use Monte Carlo simulations that fully bypass the glassy slowdown, and access equilibrium states in two-dimensional glass-forming liquids at low enough temperatures to directly probe the transition. We find that the liquid state terminates at a thermodynamic glass transition at zero temperature, which is associated with an entropy crisis and a diverging static correlation length.
Commentaires: 23 pages, 18 figures. Réf Journal: Nat. Commun. 10, 1508 (2019)
|
|
|
Coupling Space-Resolved Dynamic Light Scattering and Rheometry to Investigate Heterogeneous Flow and Nonaffine Dynamics in Glassy and Jammed Soft Matter
Auteur(s): Pommella A., Philippe A. M., Phou T., Ramos L., Cipelletti L.
(Article) Publié:
Physical Review Applied, vol. 11 p.034073 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-03029048_v1
Ref Arxiv: 1809.00506
DOI: 10.1103/PhysRevApplied.11.034073
WoS: 000462959200003
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
2 Citations
Résumé: We present a new light scattering setup coupled to a commercial rheometer operated in the plate-plate geometry. The apparatus allows the microscopic dynamics to be measured, discriminating between the contribution due to the affine deformation and additional mechanisms, such as plasticity. Light backscattered by the sample is collected using an imaging optical layout, thereby allowing the average flow velocity and the microscopic dynamics to be probed with both spatial and temporal resolution. We successfully test the setup by measuring the Brownian diffusion and flow velocity of diluted colloidal suspensions, both at rest and under shear. The potentiality of the apparatus are explored in the startup shear of a biogel. For small shear deformations, $\gamma \le 2\%$, the rheological response of the gel is linear. However, striking deviations from affine flow are seen from the very onset of deformation, due to temporally and spatially heterogeneous rearrangements bearing intriguing similarities with a stick-slip process.
|
|
|
Hierarchical landscape of hard disk glasses
Auteur(s): Liao Qinyi, Berthier L.
(Article) Publié:
Physical Review X, vol. 9 p.011049 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02092636_v1
Ref Arxiv: 1810.10256
DOI: 10.1103/PhysRevX.9.011049
WoS: 000461916500001
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
9 Citations
Résumé: We numerically analyse the landscape governing the evolution of the vibrational dynamics of hard disk glasses as the density increases towards jamming. We find that the dynamics becomes slow, spatially correlated, and starts to display aging dynamics across an avoided Gardner transition, with a phenomenology that resembles three dimensional observations. We carefully analyse the behaviour of single glass samples, and find that the emergence of aging dynamics is controlled by the apparition of a complex organisation of the landscape that splits into a remarkable hierarchy of minima as jamming is approached. Our results show that the mean-field prediction of a Gardner phase characterized by an ultrametric structure of the landscape provides a useful description of finite dimensional systems, even when the Gardner transition is avoided.
|