The nature of laponite and its aqueous dispersions

Thompson, D. W.; Butterworth, James T

doi:10.1016/0021-9797(92)90254-j

Cited by 402 publications

(393 citation statements)

References 12 publications

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“…The particles are colloidal disks of 25 nm diameter and 1 nm thickness [8], with a negative surface charge on both faces. Laponite powder was mixed with ultra-pure water at pH =10 obtained by addition of NaOH, providing chemically stable particles [9,10]. The suspension was stirred vigorously during 15 minutes and then filtered through a Millipore Millex-AA 0.8 µm filter unit.…”

Section: Preparation and Viscometrymentioning

confidence: 99%

Aging dynamics in a colloidal glass

Abou¹,

Bonn²,

Meunier³

2001

Phys. Rev. E

182

181

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The aging dynamics of colloidal suspensions of Laponite, a synthetic clay, is investigated using dynamic light stattering (DLS) and viscometry after a quench into the glassy phase. DLS allows to follow the diffusion of Laponite particles and reveals that there are two modes of relaxation. The fast mode corresponds to a rapid diffusion of particles within "cages" formed by the neighboring particles. The slow mode corresponds to escape from the cages: its average relaxation time increases exponentially fast with the age of the glass. In addition, the slow mode has a broad distribution of relaxation times, its distribution becoming larger as the system ages. Measuring the concomitant increase of viscosity as the system ages, we can relate the slowing down of the particle dynamics to the viscosity.

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Section: Preparation and Viscometrymentioning

confidence: 99%

Aging dynamics in a colloidal glass

Abou¹,

Bonn²,

Meunier³

2001

Phys. Rev. E

182

181

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“…Using a pH c10 or pH {9 in solution leads to chemical breakdown of the clay over time. 47 Gels were spread onto glass slides layer-by-layer and dried at 25 1C in desiccators and under vacuum. While one spread and dried film (ca.…”

mentioning

confidence: 99%

Supramolecular structures in nanocomposite multilayered films

Stefanescu

Dundigalla

Ferreiro

et al. 2006

Phys. Chem. Chem. Phys.

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We investigate the multilayered structures of poly(ethylene)oxide/montmorillonite nanocomposite films made from solution. The shear orientation of a polymer-clay network in solution combined with simultaneous solvent evaporation leads to supramolecular multilayer formation in the film. The resulting films have highly ordered structures with sheet-like multilayers on the micrometer length scale. The polymer covered clay platelets were found to orient in interconnected blob-like chains and layers on the nanometer length scale. Inside the blobs, scattering experiments indicate the polymer covered and stacked clay platelets oriented in the plane of the film. The polymer is found to be partially crystalline although this is not visible by optical microscopy. Atomic force microscopy suggests that the excess polymer, which is not directly adsorbed to the clay, is wrapped around the stacked platelets building blobs and the polymer also interconnects the polymer-clay layers. Overall our results suggest the re-intercalation of clay platelets in films made from exfoliated polymer-clay solutions as well as the supramolecular order and hierarchical structuring on the nanometer, via micrometer to the centimeter length scale.

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“…Although clustering prevented us from identifying single sheets, even at very high magnification (Fig. 3b), the average feature size did correspond to the ~30 nm 2 reported for Laponite RD (Alcover et al 2000, Kleinfeld and Ferguson 1994, Nicolai and Cocard 2000, Rosta and von Gunten 1990, Thompson and Butterworth 1992.…”

Section: Microscopy Of Laponite Rdmentioning

confidence: 64%

“…Direct methods for determining particle size have relied mainly on electron microscopy, and, more recently, on atomic force microscopy (AFM) (Bickmore et al 1999, Tamura et al 1999, van Duffel et al 2001. Transmission electron microscopy (TEM) has been used extensively to characterize platelet dimensions, interlayer spacing, degree of aggregation, and relative orientation of either the single sheets or larger aggregates (Alcover et al 2000, Greene et al 1974, Kawasumi et al 1997, Kornmann et al 2001, McAtee and Henslee 1969, Sonobe et al 1999, Thompson and Butterworth 1992, Tyan et al 1999, Vaia et al 1996. Due to the relative transparency of a single clay sheet, however, the images reported usually give only a cross-sectional view of the platelets.…”

Section: Introductionmentioning

confidence: 99%

A method for imaging single clay platelets by scanning electron microscopy

2004

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Summary:A method for preparing and observing clay platelets for size and shape analysis using scanning electron microscopy (SEM) was developed. Samples of the clay platelets were prepared by polyelectrolyte-assisted adsorption onto a pyrolytic graphite surface. The use of graphite as a substrate was advantageous because of the low number of secondary electrons emitted from it during imaging by SEM. The resulting low background noise allowed the emission from the ~1 nm thick clay sheets to be clearly visualized. Images of centrifuged montmorillonite showed large exfoliated platelets with lateral dimensions between 200 and 600 nm. In contrast, uncentrifuged montmorillonite appeared to contain a large amount of unexfoliated clusters. Although it was not possible to obtain high-quality images of the smaller sheets of Laponite RD, the images of this material did contain size features comparable to the ~30 nm 2 size reported previously using light scattering, as well as transmission electron and atomic force microscopies.

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The nature of laponite and its aqueous dispersions

Cited by 402 publications

References 12 publications

Aging dynamics in a colloidal glass

Aging dynamics in a colloidal glass

Supramolecular structures in nanocomposite multilayered films

A method for imaging single clay platelets by scanning electron microscopy

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