Polyelectrolyte microgels, nanoparticles

Mei Y, Lu Y, Polzer F, Ballauff M, Drechsler M (2007) Catalytic activity of palladium nanoparticles encapsulated in spherical polyelectrolyte brushes and core-shell microgels. Chem Mater 19 1062-1069... 

The focus of this chapter is the use of both the spherical polyelectrolyte brashes and microgel particles as carrier systems for novel metal nanoparticles, which can be used for catalysis in aqueous media, that is, under very mild conditions. Thus, the composite systems of metallic nanoparticles and polymeric carrier particles allows us to do green chemistry and conduct chemical reactions in a very efficient way. This approach can open new possibilities for catalytic application of metal composite particles in different reactions and represents a typical example of mesotechnology Nanoscopic objects with catalytic properties are judiciously combined with polymeric carriers to serve for a given, well-defined purpose. 

Here we have reviewed our recent studies on metallic nanoparticles encapsulated in spherical polyelectrolyte brushes and thermosensitive core-shell microgels, respectively. Both polymeric particles present excellent carrier systems for applications in catalysis. The composite systems of metallic nanoparticles and polymeric carrier particles allow us to do green chemistry and conduct chemical reactions in a very efficient way. Moreover, in the case of using microgels as the carrier system, the reactivity of composite particles can be adjusted by the volume transition within the thermosensitive networks. Hence, the present chapter gives clear indications on how carrier systems for metallic nanoparticles should be designed to adjust their catalytic activity. 

These have thus far included studies of the following systems proteins, microemulsions, colloids, copolymers, micelles, liposomes, fibrinogen, internal molecular motions, liquid interfaces, fatty acids, viruses, bacteria, vesicles, viscosity, lipids, motile cells, enzymes, lipoprotein, polyelectrolytes, spores, liquid crystals, glass transmissions, sols, microgels, soot, blood plasma, nanoparticles, swelling latex, gene delivery, and intravenous fat emulsions. 

Fig. 8 FCS proves that the two differently labeled polyelectrolytes are anchored to the same PNIPAM microgel and, thus, that the layer-by-layer assembly has been successful. Top Auto- and cross-correlation function of the coated PNIPAM nanoparticles. Bottom Confocal fluorescence images of dried particles when excited at 470 nm (left) and 532 nm (right), respectively (adapted with permission from the Journal of Physical Oiemistry [137]. Copyright (2007) American Chemical Society)...

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