Structure of marginally jammed polydisperse packings of frictionless spheres

Zhang, Chi; O'Donovan, Cathal B.; Corwin, Eric I.; Cardinaux, Frédéric; Mason, Thomas G.; Möbius, Matthias E.; Scheffold, Frank

doi:10.1103/physreve.91.032302

Cited by 18 publications

(23 citation statements)

References 35 publications

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“…2(b) we show the fraction of rattlers, N r /N . It is around 6% at the lowest jamming density, φ J ≃ 0.655, which is comparable with previous results using energy minimization in three dimensions for binary [5,31] and polydisperse [69] systems. Interestingly, the fraction of rattlers increases steadily with φ J .…”

Section: A Isostaticitysupporting

confidence: 90%

Exploring the jamming transition over a wide range of critical densities

2017

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We numerically study the jamming transition of frictionless polydisperse spheres in three dimensions. We use an efficient thermalisation algorithm for the equilibrium hard sphere fluid and generate amorphous jammed packings over a range of critical jamming densities that is about three times broader than in previous studies. This allows us to reexamine a wide range of structural properties characterizing the jamming transition. Both isostaticity and the critical behavior of the pair correlation function hold over the entire range of jamming densities. At intermediate length scales, we find a weak, smooth increase of bond orientational order. By contrast, distorted icosahedral structures grow rapidly with increasing the volume fraction in both fluid and jammed states. Surprisingly, at large scale we observe that denser jammed states show stronger deviations from hyperuniformity, suggesting that the enhanced amorphous ordering inherited from the equilibrium fluid competes with, rather than enhances, hyperuniformity. Finally, finite size fluctuations of the critical jamming density are considerably suppressed in the denser jammed states, indicating an important change in the topography of the potential energy landscape. By considerably stretching the amplitude of the critical "J-line", our work disentangles physical properties at the contact scale that are associated with jamming criticality, from those occurring at larger length scales, which have a different nature.

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Section: A Isostaticitysupporting

confidence: 90%

Exploring the jamming transition over a wide range of critical densities

2017

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“…[79] The large interfacial pressure of nanodroplets leads to large surface activities of these surfactants, and zeta potentials as large as 100 mV are not uncommon. [81] Although standard electrostatic models such as Gouy-Chapman theory are adequate for modeling the resulting electrostatic repulsions, [22,58] the strength of the electrostatic potential can lead to ranges of electrostatic repulsion that are unusually largein some cases on the order of the droplet radius or larger. [24] This results in fairly drastic changes in colloidal stability and behavior upon changes in ionic strength (again, as compared to larger droplets).…”

Section: Electrostatic Interactionsmentioning

confidence: 99%

Colloidal behavior of nanoemulsions: Interactions, structure, and rheology

Helgeson

2016

Current Opinion in Colloid & Interface Science

117

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Nanoemulsions exhibit unique behavior due to their nanoscopic dimensions, including remarkable droplet stability, interactions and rheology. These properties are significantly enhanced by nanoscopic droplet size, as well as selection of surfactant and other molecular species in solution. Electrostatic and polymer-induced interdroplet interactions are particularly powerful tools for fine-tuning the interdroplet interactions, and have led to stimuli-responsive nanoemulsion systems that provide deep insight into their unique properties. As such, nanoemulsions have emerged as powerful model systems for studying a number of colloidal phenomena including suspension rheology, repulsive and attractive colloidal glasses, aggregation processes, colloidal gelation and phase instability, and associative network formation in polymer-colloid mixtures. This review summarizes recent advances in understanding the colloidal behavior of nanoemulsions, and provides a unifying framework for understanding the various complex states that emerge, as well as perspective on emerging challenges and opportunities that will advance the use of nanoemulsions in both fundamental colloid science and technological applications. Highlights We review efforts to understand & control colloidal behavior of nanoemulsions.  Electrostatic and polymer-induced interdroplet interactions are discussed.  Repulsive interactions lead to jammed and compressed states at low volume fraction.  Attractive interactions lead to clustering, gelation and colloidal phase separation.  Nanoemulsions are model fluids to study arrested states in colloidal dispersions.

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“…4. We fix T = 298 K, since measurements have been made at room temperature, and we also fix ϕ c = 0.646, based on the known ideal limit of maximal random jamming of perfectly monodisperse spheres, recognizing that residual polydispersity in a real emulsion could shift this value somewhat (Desmond and Weeks 2014;Zhang et al 2015). We use a Fig.…”

Section: Resultsmentioning

confidence: 99%

Entropic, electrostatic, and interfacial regimes in concentrated disordered ionic emulsions

2016

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We develop a free energy model that describes two key thermodynamic properties, the osmotic pressure Π and the linear elastic shear modulus G′ p (i.e. plateau storage modulus), of concentrated monodisperse emulsions which have isotropic, disordered, droplet structures, and are stabilized using ionic surfactants. This model effectively incorporates the concept of random close packing or jamming of repulsive spheres into a free energy F that depends on droplet volume fraction ϕ and shear strain γ both below and above the a critical jamming point ϕ c ≈ 0.646. This free energy has three terms: entropic, electrostatic, and interfacial (EEI). By minimizing F with respect to an average droplet deformation parameter that links all three terms, we show that the entropic term is dominant for ϕ well below ϕ c , the electrostatic term is dominant for ϕ near but below ϕ c , and the interfacial term dominates for larger ϕ. This EEI model describes measurements of G′ p (ϕ) for charge-stabilized uniform emulsions having a wide range of droplet sizes, ranging from nanoscale to microscale, and it also is consistent with measurements of Π(ϕ). Moreover, it describes G′ p (ϕ) for similar nanoemulsions after adding non-amphiphilic salt, when changes in the interfacial tension and the Debye screening length are properly taken into account. By unifying existing approaches, the EEI model predicts constitutive properties of concentrated ionic emulsions that have disordered, out-ofequilibrium structures through near-equilibrium free energy minimization, consistent with random driving Brownian excitations.

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Structure of marginally jammed polydisperse packings of frictionless spheres

Cited by 18 publications

References 35 publications

Exploring the jamming transition over a wide range of critical densities

Exploring the jamming transition over a wide range of critical densities

Colloidal behavior of nanoemulsions: Interactions, structure, and rheology

Entropic, electrostatic, and interfacial regimes in concentrated disordered ionic emulsions

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