Nucleation continued

The debate as to which mechanism controls particle nucleation continues. There is strong evidence the HUFT and coagulation theories hold tme for the more water-soluble monomers. What remains at issue are the relative rates of micellar entry, homogeneous particle nucleation, and coagulative nucleation when surfactant is present at concentrations above its CMC. It is reasonable to assume each mechanism plays a role, depending on the nature and conditions of the polymerization (26). 

Nucleation continues by secondary mechanisms and growth continues throughout the run until the batch achieves equilibrium and/or is dumped... 

Supersaturation remains high and primary nucleation continues to occur... 

The final mean particle size and PSD will be determined by the number of nuclei created by these steps. If nucleation continues throughout the addition, the mean particle size will be small, perhaps < 10 pm, and the PSD will be broad and possibly bimodal because of the large number of nuclei produced and the conditions allowing some crystals to grow while nucleation is creating small crystals. 

Since Si is preferentially dq)leted from the carbide, carbon concentrations in those local regions are increased so that carbon clusters may actuaOy form on thinner r ons of the carbide, close to the Si substrate. The etching, cluster formation, and diamond nucleation continue until the surfrce is eventually covered with diamond nuclei. 

Figure 4.6. The thermal process for glass ceramics. After shaping with glass techniques nucleation continues until the proper concentration is reached. The nuclei are then grown at a temperature that does not favor additional nucleation.

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