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  1. Gerhard Lagaly

Published Online: 15 JAN 2007

DOI: 10.1002/14356007.a07_341.pub2

Ullmann's Encyclopedia of Industrial Chemistry

Ullmann's Encyclopedia of Industrial Chemistry

How to Cite

Lagaly, G. 2007. Colloids. Ullmann's Encyclopedia of Industrial Chemistry. .

Author Information

  1. Institut für Anorganische Chemie der Universität Kiel, 24098 Kiel, Germany

Publication History

  1. 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
5.Colloid Stability
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.