Colloidal model particles from

Synthesis and Characterization of Colloidal Model Particles Made from Organoalkoxysilanes... 

Figure 19 Model of the preparation of colloidal C02B particles from water-in-oil microemulsion.

The remainder of this contribution is organized as follows. In section C2.6.2, some well studied colloidal model systems are introduced. Methods for characterizing colloidal suspensions are presented in section C2.6.3. An essential starting point for understanding the behaviour of colloids is a description of the interactions between particles. Various factors contributing to these are discussed in section C2.6.4. Following on from this, theories of colloid stability and of the kinetics of aggregation are presented in section C2.6.5. Finally, section C2.6.6 is devoted to the phase behaviour of concentrated suspensions. 

Fig. 9.2.19 High-resolution TEM image of a colloidal silver particle observed along [111] and its schematic model. (From Ref. 39.)...

So far, we have focused on how to deal with the variations in the sizes and shapes of colloidal particles encountered in practice. However, in recent years another equally important and highly useful perspective in the use of colloids has emerged from viewing the variations in size and shape (and surface chemistry) as controllable parameters. The question is, Can we control the shapes and sizes of the particles to produce model particles that can be used to study properties of colloids and to develop new uses for colloids The answer is yes (within reason). 

In contrast to the modeling methods described above, simulation methods approach the mathematical description of colloid aggregation kinetics from a fundamentally different viewpoint these methods track particle and aggregate movement over one-, two-, or three-dimensional space. This chapter will only provide a brief introduction and overview of the types of simulation methods that have been developed, as this is a broad and growing field of research worthy of numerous volumes alone. The following discussion will proceed by defining four categories of simulations as follows, and as outlined in Table 3. 

As noted above, the models applied to measured Th distributions do not include desorption or disaggregation. Neither do they include parallel sorption of dissolved Th to multiple size classes of particles, although some studies have found evidence for parallel sorption of thorium to multiple size classes of colloids and particles (Quigley et al., 2001). State-of-the-art models do include these features, as well as a weU-resolved spectrum of particle size classes ranging from 1 nm to 100 p,m (Figure 3(c) Burd et al., 2000). The next step in this area of research will be to find clever methods to test these more elaborate models using results from laboratory and field studies. 

An interesting implication of a colloidal model as suggested by Pratt for UF resins lies in the possible structures that may result from the hardened coalesced material. If colloidal particles do form oligomeric UF condensates, the process of coalescing should be ordered in a systematic way. 

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