Study of Ca2+-induced silica coagulation by small angle scattering

Zerrouk, Robert; Foissy, A.; Mercier, R.; Chevallier, Yvonnick; Morawski, J. C.

doi:10.1016/0021-9797(90)90441-p

Cited by 38 publications

(44 citation statements)

References 13 publications

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“…This appears reasonable in comparison with the value of the particle diameter specified by the supplier, 120 ,~. While the apparent dip in In(I) at about K 2 = 0.0035 may be subject to a large error, the fact that the product rpK = 4.5 at the dip may hint that the 1 wt% sample is reasonably mono-dispersed (Zerrouk et al 1990). In spite of this, there is another apparent Guinier line with Rg = 150 A, in the range K 2 < 0.0002 (RgK < 1.7).…”

mentioning

confidence: 65%

Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

1996

Clays and clay miner.

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Abstract--Ludox HS Sit 2 sols at high concentrations show a peak in small angle x-ray scattering (SAXS) reminiscent to a "structure." The appearance of such a peak was found to depend crucially on the thickness of the sample cell used for SAXS measurements. The thinner the cell used, the more prominent the peak. When the thickness was larger than 2 rnm, it was no longer observable. When sols were treated with activated charcoal powders (in order to remove a surfactant) the peak became less prominent.For the cases where clear features for structure were absent (thick sample regime), the Smoluchowski scheme was utilized to study the nature of sols. Namely, the distribution of the Smoluchowski species were estimated by numerically calculating the size distribution of particles directly from SAXS data. The distribution was found basically bimodal, and the main distribution peak, particularly for dilute sols (less than 5 wt%), was consistent with primary particles of Sit2. The second distribution peak was strongly dependent on the concentration of Sit2 particles. The observed trend was that the higher the concentration of Sit 2 particles, the more prominent the second distribution peak and the locus of the maximum tended to move toward a smaller value in diameter. This behavior of the second distribution peak of the Smoluchowski species is no doubt a manifestation of the interparticle correlation. The observation of such behavior may provide a convenient means to characterize sols with interparticle correlation. This method was also applied for characterizing gels formed when the pH values were altered.

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confidence: 65%

Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

1996

Clays and clay miner.

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“…The available redundant information provides excellent guidance to build realistic surface models that are essential for predictive simulations ( Figure 1 and Supporting Information). [50][51][52][53][67][68][69][70][71] As an example, the sensitivity of surface ionization is graphically illustrated for common amorphous silica nanoparticles prepared by Stöber-like synthesis ( Figure 2). …”

Section: A Silica Surface Model Databasementioning

confidence: 99%

“…19, [50][51][52][53] The aim of this contribution is the introduction of a silica surface model database that covers all types of surface chemistry and pH, as well as the introduction of a silica force field that resolves limitations of prior models. Our team has previously proposed accurate force fields for related minerals, in comparison to which silica is a relatively simple case.…”

Section: Introductionmentioning

confidence: 99%

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

et al. 2014

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Silica nanostructures find applications in drug delivery, catalysis, and composites, however, understanding of the surface chemistry, aqueous interfaces, and biomolecule recognition remain difficult using current imaging techniques and spectroscopy. A silica force field is introduced that resolves numerous shortcomings of prior silica force fields over the last thirty years and reduces uncertainties in computed interfacial properties relative to experiment from several 100% to less than 5%. In addition, a silica surface model database is introduced for the full range of variable surface chemistry and pH (Q 2 , Q 3 , Q 4 environments with adjustable degree of ionization) that have shown to determine selective molecular recognition. The force field enables accurate computational predictions of aqueous interfacial properties of all types of silica, which is substantiated by extensive comparisons to experimental measurements. The parameters are integrated into multiple force fields for broad applicability to biomolecules, polymers, and inorganic materials (AMBER, CHARMM, COMPASS, CVFF, PCFF, INTERFACE force field).We also explain mechanistic details of molecular adsorption of water vapor, as well as significant variations in the amount and dissociation depth of superficial cations at silica-water interfaces that correlate with zeta-potential measurements and create a wide range of aqueous environments for adsorption and self-assembly of complex molecules. The systematic analysis of binding conformations and adsorption free energies of distinct peptides to silica surfaces is reported separately in a companion paper. The models aid to understand and design silica nanomaterials in 3D atomic resolution, and are extendable to chemical reactions.

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“…26 This study focuses on the effects of pH and particle size that modulate ionization, surface structure, and specific peptide adsorption ( Figure 1). 9,[38][39][40][41] The chosen peptides include consensus silica binding sequences composed of seven amino acids with different net charge (-1, 0, +1) and hydrophilicity that were previously identified by phage display (Table 1). 10 The chosen nanoparticles are of diameters 28 nm, 82, nm, and 210 nm, and have undergone characterization of their surface chemistry by BET, BJH, TGA, TEM, SEM, and ζ-potential measurements (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Prediction of Specific Biomolecule Adsorption on Silica Surfaces as a Function of pH and Particle Size

et al. 2014

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Silica nanostructures are biologically available and find wide applications for drug delivery, catalysts, separation processes, and composites. However, specific adsorption of biomolecules on silica surfaces and control in biomimetic synthesis remain largely unpredictable. In this contribution, the variability and control of peptide adsorption on silica nanoparticle surfaces is explained as a function of pH, particle diameter, and peptide electrostatic charge using molecular dynamics simulations with the CHARMM-INTERFACE force field. Adsorption free energies and specific binding residues are analyzed in molecular detail, providing experimentally elusive, atomic-level information on the complex dynamics of aqueous electric double layers in contact with biological molecules. Tunable contributions to adsorption are described in the context of specific silica surface chemistry, including ion pairing, hydrogen bonds, hydrophobic interactions, and conformation effects. Remarkable agreement is found for computed peptide binding as a function of pH and particle size versus experimental adsorption isotherms and zetapotentials. Representative surface models were built using characterization of the silica surfaces by TEM, SEM, BET, TGA, ζ-potential, and surface titration measurements. The results show that the recently introduced interatomic potentials (Emami et al. Chem. Mater. 2014, 26, 2647 enable computational screening of a limitless number of silica interfaces to predict the binding of drugs, cell receptors, polymers, surfactants, and gases under realistic solution conditions at the scale of 1 to 100 nm. The highly specific binding outcomes underline the significance of the surface chemistry, pH, and topography.3

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Study of Ca2+-induced silica coagulation by small angle scattering

Cited by 38 publications

References 13 publications

Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

Prediction of Specific Biomolecule Adsorption on Silica Surfaces as a Function of pH and Particle Size

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Study of Ca2+-induced silica coagulation by small angle scattering

Cited by 38 publications

References 13 publications

Study of a Commercial SiO2 Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

Study of a Commercial SiO2 Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution

Prediction of Specific Biomolecule Adsorption on Silica Surfaces as a Function of pH and Particle Size

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Product

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Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

Study of a Commercial SiO₂ Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme