The Study of Gel Formation and Flocculation in Aqueous Clay Dispersions by Optical and Rheological Methods

Abstract

Optical and rheological methods have been used to study the gelling and flocculation of aqueous dispersions of a synthetic hectorite-Jike clay, Laponite CP, on the addition of electrolytes or water miscible organic solvents. There is a positive correlation between the yield value and turbidity when the dispersions are flocculated with electrolyte, Addition of polar solvent, however, shows no such correlation, only a sudden change from very clear to very cloudy dispersion. while the yield value increases gradually until gross flocculation takes place. It is suggested that two different flocculation mechanisms lire being observed.

Surfactant Adsorption on a Clay Mineral: Application of Radiation Scattering

“…The measured diffraction pattern is shown in Figure 4a and displays a peak position corresponding to a layer spacing of 1.26 nm. This spacing, representing the thickness of the clay plate in a stacked configuration with interstitial Na + ions, is consistent with previous X-ray and neutron data [25][26][27][28][29] and is also consistent with our estimate of a platelet thickness of 1.1 nm. The precoated clay/surfactant complexes were also dried and deposited on the wafer, and the X-ray patterns were observed (Figure 4b).…”

“…The properties of CTAB are well-known, and the data published by Berr and coauthors on the structure of CTAB micelles are particularly relevant. Also, the properties of the clay have been documented by the manufacturers and by other investigators. − Laponite closely resembles the natural clay hectorite, with a basic unit consisting of a layered hydrous magnesium silicate platelet of diameter 25−30 nm with a thickness of approximately 1 nm. The platelet itself is composed of a pair of tetrahedrally coordinated silica sheets that sandwich an octahedrally coordinated sheet of magnesium oxide.…”

“…Also, the properties of the clay have been documented by the manufacturers 24 and by other investigators. [25][26][27][28][29] Laponite Langmuir 1997, 13, 5276-5282 S0743-7463(96)02048-3 This article not subject to U.S. Copyright.…”

Metachromasy in Clay Minerals. Part I. Sorption of Methylene‐Blue by Montmorillonite

“…Above pH 2.4 the amount of methylene -blue necessary to reach the end point increases non -linearly as the pH rises. This is probably caused by the release of aluminium ions from the clay by the protons [16]. As will be shown in a later stage, aluminium ion is not exchanged with methylene -blue proving that the affinity of aluminium to montmorillonite is higher than that of methylene-blue.…”

Dr Barbara S. Neumann: clay scientist and industrial pioneer; creator of Laponite®

“…From this point, Barbara further developed her second scientific passion (along with clay science and mineralogy): the rheological applications of clays as additives to a variety of formulations and other purposes (Taylor & Neumann, 1968; Neumann & Sansom, 1970). At an early stage, Barbara spotted the exciting potential of Laponite® materials as powerful thickeners of aqueous rather than solvent-based formulations.…”