AGGREGATE behavioural synthesis

For a general review on supramolecular chemistry with dendrimers, the reader is referred to an excellent paper of Zimmerman et al. [18]. Because of our acquaintance with the polylpropylene imine) dendrimers, we will restrict ourselves in this Chapter to some examples of supramolecular behaviour of these systems as investigated in our laboratory. Three systems will be discussed (Figure 1) the dendritic box, which can encapsulate guest molecules, the polystyrene-poly(propy-lene imine) block copolymer superamphiphiles, and alkyl-decorated dendrimers, which function as unimolecular micelles, and show surprising aggregation behaviour. However, first the synthesis and properties of the poly(propylene imine) dendrimers will be discussed to demonstrate some typical dendrimer features. 

Efforts at synthesis and studies of temperature-dependent solution behaviour of these chemically hydrophobized polyacrylamides are now in progress. However, it is reasonable to point out that in this case, contrary to the hydrophilization of the hydrophobic precursor, the problems associated with additional swelling of the globular core (as the modification proceeds) are absent however, the problem of the choice of working concentration for the precursor is still present since above the coil overlapping concentration the intermolecular aggregation processes at elevated temperatures can compete with the intramolecular formation of core-shell structures. 

We present experimental results on the ability of water-in-oil reverse micelles for synthesis and stabilization of Au, Agl and dye J-aggregate nanoparticles as well for selfassembling of hybrid nanosystem, consisting of semiconductor nanoparticles and dye J-aggregate. The preparation, spectral behaviour and properties of this nanoparticles are discussed. 

Sasaki T., Watanabe M., Hashizume H., Yamada H., Nakazawa H. Macromolecule-like aspects for a colloidal suspension of an exfoliated titanate. Pairwise association of nanosheete and dynamic reassembling process initiated from it. J. Am. Chem. Soc. 1996 118 8329-8335 Sasaki T., Nakano S., Yamauchi S., Watanabe M. Fabrication of titanium dioxide thin flakes and their porous aggregate. Chem Mater. 1997 9 602-608 Sathiyakumar M., Gnanam F.D. Synthesis of sol-gel derived alumina powder effect of milling and calcination temperatures on sintering behaviour. Brit. Ceram. Trans. 1999 98 87-92... 

Buijnsters, P. J. J. A., Garcia Rodriguez, C. L., WiUighagen, E. L. et al. (2002) Cationic gemini surfactants based on tartaric acid synthesis, aggregation, monolayer behaviour and interaction with DNA. Eur. J. Org. Chem, 8, 1397-1406. 

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