Organic polycation components

Recently, we (82) and others (82-84) have shown that similar hetero-structures can be prepared by using two-dimensional inorganic sheets (made by exfoliation of various lamellar solids) in place of the organic polyanion. This technique offers a potentially powerful alternative to the construction of multi-component electron transfer systems, because it can, in principle, be used to stack up an arbitrary number of redox-active polymers without interpenetration (85). This chapter describes the preparation and photochemistry of simple multilayer composites on high-surface-area silica. Specifically, the synthesis and electron transfer kinetics of systems containing a polycationic sensitizer, poly-[Ru(bpy)2(vbpy)(Cl)2] (1), (abbreviated [Ru(bpy)3 ]n bpy = 2,2 -bipytidine and vbpy = 4-vinyl-4 -methyl-2,2 -bipyridine), and an electron-acceptor polycation poly[(styrene-co-]V-vinylbenzyl-N -methyl-4,4 -bipyridine)(Cl)2] (2), (PS-MV ) are presented. Using a solution-phase electron donor, 3, as the third electroactive component, it was possible to prepare and study the photoinduced electron transfer reactions of several different diad and triad combinations. 

Layered composite films can be directly prepared by alternate deposition or vacuum filtration of the mixed dispersions of both components. For instance, PANl/Prussian blue composite films have been fabricated using layer-by-layer assembly of the polycation PANI and a negatively ionized Prussian blue nanoparticle dispersion (DeLongchamp and Hammond, 2004). The resultant organic/inorganic nanocomposites exhibited good smoothness and a classical linear increase in film thickness with assembly steps. In... 

Polycations are also used as components of hybrid organic-inorganic DDSs. The most frequent of them are those where the clays of the bentonite type are used as the inorganic component. Other hybrid systems where cationic polymers are used are those based on hydrojyapatite and silicone. 

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