Evaluation of Dispersion Stability

✍ Scribed by Dechun Fu; Richard E. Riman

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 286 KB
• Volume: 157
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1993.1201

✦ Synopsis

The objective of this study is to develop a new approach for identifying stable versus unstable colloidal suspensions. The new method, referred to as variable sedimentation mode (VSM) analysis, examines the sedimentation behavior of particles in gravitational and centrifugal fields. Systems whose particle size distributions are independent of the sedimentation mode employed are deemed stable while those whose particle size distributions vary according to sedimentation mode are considered unstable. For an aqueous titania dispersion, a discontinuity in the breadth of the particle size distribution is observed as the (\mathrm{pH}) approaches the isoelectric point. This discontinuity defines the (\mathrm{pH}) region of colloidal instability. In contrast, systems such as aqueous sodium hexametaphosphate-stabilized titania dispersions, which display no isoelectric point, exhibit no discontinuity. 1993 Academic Press, Inc.