Oil-in-water emulsions were prepared using montmorillonite clay platelets, pre-treated with quaternary amine surfactants. In previous work, cetyl trimethylammonium bromide (CTAB) has been used. In this study, two more hydrophilic quaternary amine surfactants, Berol R648 and Ethoquad C/12, were used and formed Pickering emulsions, which were more stable than the emulsions prepared using CTAB coated clay. The droplets were also more mono-disperse. The most hydrophilic surfactant Berol R648 stabilizes the emulsions best. Salt also plays an important role in forming a stable emulsion. The droplet size decreases with surfactant concentration and relatively mono-disperse droplets can be obtained at moderate surfactant concentrations. The time evolution of the droplet size indicates a good stability to coalescence in the presence of Berol R648. Using polarizing microscopy, the clay platelets were found to be lying flat at the water oil interface. However, a significant fraction (about 90%) of clay stayed in the water phase and the clay particles at the water-oil interface formed stacks, each consisting of four clay platelets on average.
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http://dx.doi.org/10.1016/j.jcis.2011.01.046 | DOI Listing |
J Chem Phys
December 2024
Department of Chemical Engineering, University of Western Australia, Crawley 6009, Australia and Centre for Microscopy, Characterization and Analysis, University of Western Australia, Crawley 6009, Australia.
Salt strengthened the bond formed and quickened the bonding process of 3-5 wt. % hectorite gels during the structural rejuvenation process. This even occurred at 0.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
November 2024
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, PR China; CAS Key Laboratory for Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, PR China. Electronic address:
Eur Phys J E Soft Matter
September 2024
Institut de Chimie Séparative de Marcoule, BP 17171, 30207, Bagnols-sur-Cèze, France.
We describe the different mixed colloidal solutions that can be obtained when mixing equivalent quantities of a synthetic anionic clay to surfactants forming lamellar phases in the absence of added salt. The important quantity driving toward insertion or depletion is the osmotic pressure, of the lamellar phase and of the clay alone. Competition for water is the main driving force toward dispersion, inclusion or exclusion (phase separation).
View Article and Find Full Text PDFJ Stroke Cerebrovasc Dis
November 2024
Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA. Electronic address:
Background: In the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial, dual antiplatelet therapy (DAPT) was associated with reduced disability attributable to the index stroke compared to antiplatelet monotherapy. However, it is unknown whether earlier treatment with DAPT versus aspirin is associated with greater benefit.
Methods: We analyzed patients enrolled in POINT with minor ischemic stroke who had available data recording the treatment initiation time and modified Rankin Scale (mRS) at 90 days.
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