Stability of dispersions in polar media |
| |
| Institution: | 1. Department of Applied Chemistry, Faculty of Science, Malayer University, Malayer, Iran;2. Department of Physical Chemistry, Islamic Azad University of Tabriz, Tabriz, Iran;1. Department of Materials Science and Engineering and Chemical Engineering, University Carlos III, Madrid, Spain;2. Institute for Ceramic and Glass, CSIC, Madrid, Spain;3. Hispano Italiana de Revestimientos, S.A., Santander, Spain;1. Institute of Production Engineering and Machine Tools, An der Universität 2, 30823 Garbsen, Germany;2. CeramTec GmbH, CeramTec-Platz 1-9, 73207 Plochingen, Germany |
| |
| Abstract: | The stability of dispersions in polar organic media was reviewed comparing with that of in aqueous and non-polar media. Structure and properties of the double layer of AgI in water-ethylene glycol were studied and the stability of the dispersions was related to the study of the double layer.Coagulation concentrations of Ag,AgI and α-FeOOH dispersions in methanol, ethanol 1,2-propanol and acetone by the addition of electrolytes were determined.Coagulation by monovalent counterions is due to double layer compression. With bi- and multivalent counterions or in low dielectric constant-solvents coagulation is primarily caused by charge neutralization.The effect of an ionic surfactant, AOT on the stability of TiO2 or α-Fe2O3 in water-p-dioxane mixtures was studied. AOT behaved as a coagulating agent in polar media ( ? = 10–50) , though it worked as a dispersing agent in non-polar (dioxane) and water rich media. AOT accordingly coagulated the dispersion a carbon black in 2-butanone, though a nonionic surfactant did not so. Desolvation from the particle surface is considered to be an important origin of coagulation by AOT in polar media, because AOT is not adsorbed on particles and comsiderably dissociates into ions in 2-butanone. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
