Ultrasmall- and small-angle X-ray scattering of smectite clay suspensions

Morvan, Mikel; Espinat, D.; Lambard, J.; Zemb, Thomas

doi:10.1016/0927-7757(93)02656-y

Cited by 164 publications

(134 citation statements)

References 27 publications

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“…Since the polyelectrolyte solutions remain liquid-like even at higher concentrations, the observed qualitative different behavior of the structure factors of Laponite may be considered as indicative of the sol-gel transition at higher concentrations. Notice that the val-ues of S M (q = 0) for the Laponite suspensions under considerations are smaller than 1 and decrease with increasing concentration in contrast to strong small q upturns which have been observed experimentally for clay suspensions in the gel phase [18,20,21,71,72,73,74,75], polyelectrolyte gels [76] and mixtures [77], polystyrenesulfonate ion exchange resins [78], and low ionic strength polyelectrolyte solutions [79,80,81]. These strong upturns signal strong concentration fluctuations indicative of aggregation, or spinodal instability reminiscent of the behaviour observed in recent computer simulations [82] and PRSIM integral equations [38] of mixtures of oppositely charged particles.…”

Section: A Static Scattering Experiments: Consistency Checkmentioning

confidence: 98%

Effective interaction of charged platelets in aqueous solution: Investigations of colloid laponite suspensions by static light scattering and small-angle x-ray scattering

Harnau

Rosenfeldt

et al. 2005

Phys. Rev. E

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We study dilute aqueous solutions of charged disk-like mineral particles (Laponite) by a combination of static light scattering (SLS) and small-angle x-ray scattering (SAXS). Laponite solutions are known to form gels above a certain critical concentration that must be described as non-equilibrium states. Here we focus on the investigation by SLS and SAXS at concentrations below gelation (c < 0.016 g/L) and at low concentrations of added salt (0.001 and 0.005 mM). Thus, we have obtained the scattering function of single Laponite platelets as well as the structure factor describing their interaction at finite concentration. A detailed analysis of the combined sets of data proves that the solutions are in a well-defined equilibrium state. Moreover, this analysis demonstrates the internal consistency and accuracy of the scattering functions obtained at finite concentrations. We find that Laponite particles interact through an effective pair potential that is attractive on short range but repulsive on longer range. This finding demonstrates that Laponite solutions exhibit only a limited stability at the concentration of added salt used herein. Raising the ionic strength to 0.005 mM already leads to slow flocculation as is evidenced from the enhanced scattering intensity at smallest scattering angles. All data strongly suggest that the gelation occurring at higher concentration is related to aggregation.

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Section: A Static Scattering Experiments: Consistency Checkmentioning

confidence: 98%

Effective interaction of charged platelets in aqueous solution: Investigations of colloid laponite suspensions by static light scattering and small-angle x-ray scattering

Harnau

Rosenfeldt

et al. 2005

Phys. Rev. E

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“…Norrish 61 suggested that the repulsive force caused by interacting double layers was responsible for the gel structure. There have been signicant developments in the ability to study the structure of clay dispersions using techniques such as cryo-TEM, 80 ultra small angle X-ray scattering, 81 X-ray uorescence microscopy, 82 environmental scanning electron microscopy, 83 transmission X-ray microscopy, [84][85][86] and differential interference contrast microscopy. 87 This has led to some convergence of the views on the structure of clay gels.…”

Section: Sol-gel Transitionsmentioning

confidence: 99%

Smectite clay – inorganic nanoparticle mixed suspensions: phase behaviour and rheology

2015

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Smectite clay minerals and their suspensions have long been of both great scientific and applications interest and continue to display a remarkable range of new and interesting behaviour. Recently there has been an increasing interest in the properties of mixed suspensions of such clays with nanoparticles of different size, shape and charge. This review aims to summarize the current status of research in this area focusing on phase behaviour and rheological properties. We will emphasize the rich range of data that has emerged for these systems and the challenges they present for future investigations. The review starts with a brief overview of the behaviour and current understanding of pure smectite clays and their suspensions. We then cover the work on smectite clay-inorganic nanoparticle mixed suspensions according to the shape and charge of the nanoparticles -spheres, rods and plates either positively or negatively charged. We conclude with a summary of the overarching trends that emerge from these studies and indicate where gaps in our understanding need further research for better understanding the underlying chemistry and physics.

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“…The concentration effect is much more pronounced in montmorillonite systems, being observable even at a 1% clay concentration (Figure 2b). There is a broad hump on the 3% and 5% curves between q = 0.1 and 0.2 nm -~ which is usually believed to account for the structure factor maximum of a scattering system (Morvan et al, 1994). To show the concentration effect, the scattering curves of 0.5%, 1% and 2% were extrapolated to zero concentration by a linear Zimm plot.…”

Section: Resultsmentioning

confidence: 99%

“…These studies have both theoretical and industrial significance. The thickness, interparticle spacing in hydrated states, and the influence of interparticle forces fall into the characterization length scale of SAXS and have been investigated by this method in the past (Hight et al, 1960(Hight et al, , 1962Taylor and Schmidt, 1969;Morvan et aL, 1994;Pignon et al, 1997;Saunders et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Thickness and Surface Characteristics of Colloidal 2:1 Aluminosilicates Using an Indirect Fourier Transform of Small-Angle X-Ray Scattering Data

Shang

Rice

Lin

2001

Clays and clay miner.

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Abstract--An indirect Fourier transformation applied to small-angle X-ray scattering data has been used to determine the thickness and surface properties of two common clay minerals. For an illite system, the particle density distribution function (PDDF) generated by the analysis gave a correct description of particle geometry, and the calculated electron density profile was in accordance with the theoretical electron density distribution for this mineral. This approach provides the opportunity to determine the thickness of fundamental particles of illite while avoiding the difficulties encountered in other methods. Both the PDDF and the electron density profile accurately predict the thickness of Na-montmorillonite layers, and the results suggest that an electron inhomogeneity exists at the interface of this mineral.

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Ultrasmall- and small-angle X-ray scattering of smectite clay suspensions

Cited by 164 publications

References 27 publications

Effective interaction of charged platelets in aqueous solution: Investigations of colloid laponite suspensions by static light scattering and small-angle x-ray scattering

Effective interaction of charged platelets in aqueous solution: Investigations of colloid laponite suspensions by static light scattering and small-angle x-ray scattering

Smectite clay – inorganic nanoparticle mixed suspensions: phase behaviour and rheology

Thickness and Surface Characteristics of Colloidal 2:1 Aluminosilicates Using an Indirect Fourier Transform of Small-Angle X-Ray Scattering Data

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