Nanocomposites, separation efficiency

Intercalation refers to the inclusion of molecules between the layers. Exfoliation refers to the separation of the layers. In other words, intercalated polymer chains are sandwiched in between clay layers. In exfoliated nanocomposites the individual layers are separated, and somewhat uniformly dispersed in the polymeric matrix. This class of materials has been widely investigated because of their unique properties. The efficiency of PPV-related electroluminescent devices is summarized in Table 3.5. 

Li conducting pathways at the ceramic surface [44-46]. Therefore, according to this model, the structural modifications at microscopic levels promote consistent enhancement in the transport properties of the electrolyte. In addition, the all-solid configuration (no addition of liquids) gives to these nanocomposite electrolytes a high compatibility with the lithium metal electrode [47-50], all these properties making them suitable for use as safe and efficient separators in rechargeable lithium batteries [51]. 

Besides, a possible mechanism for the photocatalytic activity of the CdS-ATP nanocomposite was proposed. Under visible-light irradiation, CdS nanocrystals are activated. The photogenerated electrons transfer from the conduction band of CdS into ATP and accumulate at the lower-lever conduction band of ATP to generate hydrogen, while holes accumulate at the valence band of CdS. Hence, the CdS-ATP nanocomposites can increase photoactivity as a result of the efficient separation of the photogenerated electron-hole pairs. 

Montmorillonite, hectorite, and saponite are the most widely investigated clays. Their structure and formula are shown in Figure 9.1 and Table 9.1, respectively. Montmorillonite is a very popular choice for nanocomposites because of its small particle size (<2 pm) and hence the easy diffusion of polymer into the clay particles. They also have high aspect ratios (10-2000) and high swelling capacity, which are essential for efficient intercalation of the polymer. The physical mixture of a polymer and a clay may not form a nanocomposite. This situation is analogous to that in a polymer blend, and separation into discrete phases takes place in most cases. Pristine clay usually contains hydrated Na+ or K+ ions. Obviously,... 

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