A Wetting of the Powder

For a liquid to disperse a finely divided solid, it must first wet each particle cluster completely. This will involve, at least in the final stages of wetting, a spreading type of wetting, in which the air is completely displaced from the surface by the wetting medium. The driving force for this process, as we have seen, is the spreading coefficient  

Once the particle clusters have been wet by the suspending liquid, they must be dispersed in it. This may be accomplished by the surface-active agent in two ways  

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