Published Online: 15 JAN 2007
Copyright © 2002 by Wiley-VCH Verlag GmbH & Co. KGaA
Ullmann's Encyclopedia of Industrial Chemistry
How to Cite
Lagaly, G. 2007. Colloids. Ullmann's Encyclopedia of Industrial Chemistry. .
- Published Online: 15 JAN 2007
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The article contains sections titled:
|2.||Colloidal Systems in Industrial Uses|
|3.||Preparation of Colloidal Particles|
|4.||Properties of Colloidal Systems|
|6.||Factors Controlling Colloid Stability|
Industrial uses of colloidal systems such as pigment and paint production, coating processes, ceramics, printing, emulsification and de-emulsification, oil recovery, filler and composite materials, dispersion hardening, civil engineering, geotechniques, soil engineering, water purification, consumer, pharmaceutical and cosmetic products, environmental protection, and many other applications require different colloidal states: stable dispersions (sols), dispersions of particles coagulated by salt addition or pH shift or flocculated by polymers, diluted dispersions or fluid highly concentrated dispersions, gels, and solid materials. The knowledge of the stabilizing mechanisms (electric and steric stabilization) provides the basis for developing colloidal systems and optimizing their properties. Depending on the stabilization mechanisms, the parameters are evaluated which are required to peptize colloidal particles in aqueous and non-aqueous solvents, to coagulate or flocculate dispersions, to avoid undesirable thinning or thickening of dispersions, to liquefy dispersions with high solid content (slips, slurries), to transform sols into gels or liquefy gels, to impart thixotropy, to impede sagging (of paints), to make systems filterable, to impede settling, to improve plastering, to avoid undesirable mechanical effects, etc. We describe the experimental methods which are needed to reveal the most important parameters responsible for these changes.