Structural and Thermodynamic Properties of Charged Silica Dispersions

Chang, Jeanne C.; Lesieur, P.; Delsanti, M.; Belloni, Luc; Bonnet-Gonnet, Cécile; Cabane, Bernard

doi:10.1021/j100043a045

Cited by 46 publications

(65 citation statements)

References 21 publications

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“…13 of Ref. [59], which appears to imply the presence of large-unit-cell crystals in dispersions similar to ours (10.2 nm silica with 9% size polydispersity).…”

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confidence: 86%

Hiding in Plain View: Colloidal Self-Assembly from Polydisperse Populations

Cabane

Artzner

et al. 2016

Phys. Rev. Lett.

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We report small-angle x-ray scattering experiments on aqueous dispersions of colloidal silica with a broad monomodal size distribution (polydispersity, 14%; size, 8 nm). Over a range of volume fractions, the silica particles segregate to build first one, then two distinct sets of colloidal crystals. These dispersions thus demonstrate fractional crystallization and multiple-phase (bcc, Laves AB 2 , liquid) coexistence. Their remarkable ability to build complex crystal structures from a polydisperse population originates from the intermediate-range nature of interparticle forces, and it suggests routes for designing self-assembling colloidal crystals from the bottom up.

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“…13 of Ref. [59], which appears to imply the presence of large-unit-cell crystals in dispersions similar to ours (10.2 nm silica with 9% size polydispersity).…”

supporting

confidence: 86%

Hiding in Plain View: Colloidal Self-Assembly from Polydisperse Populations

Cabane

Artzner

et al. 2016

Phys. Rev. Lett.

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“…These particles had a mean size of 20 nm, and a narrow distribution of diameters around this value. Each particle carried about 200 ionized SiO -sites on its surface, compensated by Na + counterions located in a diffuse layer around the particle [16].…”

Section: Repelling Particlesmentioning

confidence: 99%

“…The dispersions were made of silica particles of the same mean diameters, but they were synthesized in separate experiments. Also, the compression curves were obtained by different researchers, both using the osmotic stress technique [16,24]. The good agreement of both sets of data implies that the measured compression curve is uniquely determined by the characteristics of the particles.…”

Section: Silica Nanoparticlesmentioning

confidence: 99%

“…Pressure is applied to the pistons and the network collapses while some liquid phase is forced out through the membranes ( Figure 1). In osmotic stress experiments, the dispersion is placed inside a dialysis bag, and immersed in a large volume of an aqueous polymer solution, of known osmotic pressure [15,16]. The liquid is then extracted through its affinity for the external solution.…”

Section: Introductionmentioning

confidence: 99%

“…Model systems A number of osmotic compression experiments have been performed already on model colloidal dispersions, using osmotic stress, mechanical compression or centrifugation [3,4,[15][16][17][18]. The present paper reviews recent experiments in which aqueous dispersions of nanometric silica or clay particles were used as starting materials for the production of concentrated dispersions, aggregated suspensions, pastes (concentrated aggregated suspensions) and cakes (solid pastes).…”

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confidence: 99%

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From colloidal dispersions to colloidal pastes through solid-liquid separation processes

Madeline

Meireles

Persello

et al. 2005

Pure and Applied Chemistry

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Solid-liquid separation is an operation that starts with a dispersion of solid particles in a liquid and removes some of the liquid from the particles, producing a concentrated solid paste and a clean liquid phase. It is similar to thermodynamic processes where pressure is applied to a system in order to reduce its volume. In dispersions, the resistance to this osmotic compression depends on interactions between the dispersed particles.The first part of this work deals with dispersions of repelling particles, which are either silica nanoparticles or synthetic clay platelets, dispersed in aqueous solutions. In these conditions, each particle is surrounded by an ionic layer, which repels other ionic layers. This results in a structure with strong short-range order. At high particle volume fractions, the overlap of ionic layers generates large osmotic pressures; these pressures may be calculated, through the cell model, as the cost of reducing the volume of each cell. The variation of osmotic pressure with volume fraction is the equation of state of the dispersion. The second part of this work deals with dispersions of aggregated particles, which are silica nanoparticles, dispersed in water and flocculated by multivalent cations. This produces large bushy aggregates, with fractal structures that are maintained through interparticle surface-surface bonds. As the paste is submitted to osmotic pressures, small relative displacements of the aggregated particles lead to structural collapse. The final structure is made of a dense skeleton immersed in a nearly homogeneous matrix of aggregated particles. The variation of osmotic resistance with volume fraction is the compression law of the paste; it may be calculated through a numerical model that takes into account the noncentral interparticle forces. According to this model, the response of aggregated pastes to applied stress may be controlled through the manipulation of interparticle adhesion.

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