## Abstract The spontaneous hydrolysis of phenyl chloroformate was studied in various anionic, nonionic, zwitterionic, and cationic aqueous micellar solutions, as well as in mixed anionic–nonionic micellar solutions. In all cases, an increase in the surfactant concentration results in a decrease in
Effect of Ionic and Nonionic Solutes on the Transient and Steady States in the Settling of Charged Colloidal Particles
✍ Scribed by Josef Janča; Natalia Gospodinova; Sonia Le Hen; Milena Špı́rková
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 259 KB
- Volume
- 229
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
Centrifugation was applied to study the transport phenomena in various suspensions of charged colloidal silica particles. Isopycnic focusing of colored density marker beads was used to view the evolution of the density gradient and to determine its steady-state shape from the measured positions of the focused zones. The effect of the ionic and nonionic solutes on the transient and steady states was studied. The experimental results are discussed in relation with the published theoretical dependence of the transport coefficients on the volume fraction of the settling particles. The understanding of the transport phenomena and of the interfering particle interactions governing the formation of the density gradient and the subsequent isopycnic focusing under model static conditions is necessary for the optimization of the isoperichoric focusing field-flow fractionation dynamic experiments, but it should allow a more accurate description of the relaxation phenomena and retention in polarization field-flow fractionation as well. Some previous experimental results concerning the study of the transport phenomena of the charged silica particles in an electric field are exploited here to demonstrate the general character of the observed behavior, independent of the field nature.
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