Biomedical Engineering Reference
In-Depth Information
• Electrosteric stabilization. The addition of what usually are long-chain polyelectro-
lytes with at least one type of ionizable group, such as a carboxylic or sulfonic acid
group, combine electrostatic and steric stabilization. In this case, the adlayer can
be attached more strongly than the preceding case of polar attraction owing to the
ionization. This approach can utilize cationic and anionic polyelectroytes and it
can be used in both aqueous and organic media.
Concerning the potential energy from V struct , the effect of the nonadsorbed species in solu-
tion can increase or decrease stability [34]. This is likely to depend largely upon the type
and scale of their charge.
Initial Assessment of Suspension Stabilization
The dispersion of suspensions generally is assessed initially through simple experimenta-
tion on the settling behavior as a function of pH and/or deflocculant addition. This is done
by placing suspensions with different pH, deflocculant addition, medium, and/or solids
loading in test tubes, agitating, and allowing to settle for an extended period, usually up to a
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(i) Electrostatic stabilization
(ii) Steric stabilization
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(iii) Electrosteric stabilization
FIGURE 3.8
Principal mechanisms of suspension stabilization. (Adapted from Cao, G., Nanostructures and Nanomaterials—
Synthesis, Properties and Applications. Imperial College Press, London, 2004; Lewis, J.A. J. Am. Ceram. Soc., 83 [10]
2341-59 (2000).)
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