All colloidal mixtures are stable. We can see this from the way all colloids mixture will never generate a sediment. The term “stability” can have different meanings to different applications. When applied to colloids, a stable colloidal system is one in which the particles resist flocculation or aggregation and exhibits a long shelf-life. This will depend upon the balance of the repulsive and attractive forces that exist between particles as they approach one another. If all the particles have a mutual repulsion then the dispersion will remain stable. However, if the particles have little or no repulsive force then some instability mechanism will eventually take place.
- Particles in a dispersion may be attached together and form aggregates of increasing size which may settle out due to gravity itself.
- An initially formed aggregate is called a FLOC and its formation FLOCCULATION - this process is reversible (DEFLOCCULATION)
- If the aggregate changes to a much denser form it is said to undergo COAGULATION - this process is irreversible
- An initially formed aggregate is called a FLOC and its formation FLOCCULATION - this process is reversible (DEFLOCCULATION)
- If the aggregate changes to a much denser form it is said to undergo COAGULATION - this process is irreversible
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