Core-shell block dendrimer

Different architectures, such as block copolymers, crosslinked microparticles, hyperbranched polymers and dendrimers, have emerged (Fig. 7.11). Crosslinked microparticles ( microgels ) can be described as polymer particles with sizes in the submicrometer range and with particular characteristics, such as permanent shape, surface area, and solubility. The use of dispersion/emulsion aqueous or nonaqueous copolymerizations of formulations containing adequate concentrations of multifunctional monomers is the most practical and controllable way of manufacturing micro-gel-based systems (Funke et al., 1998). The sizes of CMP prepared in this way vary between 50 and 300 nm. Functional groups are either distributed in the whole CMP or are grafted onto the surface (core-shell, CS particles). 

Like many polymers, the fluidity or flow (rheological) properties of denrimers are of interest (Box 14.1). Dendrimers behave like soft, spherical particles, surrounded by a hard surface shell and hence are often described as core-shell type bodies. Hence the interior of dendrimers can be deformed according to the type of linkage and building blocks and my contain voids suitable for encapsulating guest species.2... 

Depending on the type of charges, polycationic PEG-P(Lys) and polyanionic PEG-P(Asp) are used for the preparation of such PIC micelles (Fig. 6). Based on recent research, core-shell type PIC micelles with a 52 nm diameter were prepared from a Zn-porphyrin-dendrimer with 32 carboxylate groups on the periphery, 32(-)DPZn, and PEG-P(Lys) block copolymers (56,57). On the contrary, when the dendrimer structure is cationic, a third-generation porph3rrin-dendrimer with 32 primary amine groups on the periphery, 32(+)DPZn, and PEG-P(Asp) were used to prepare a PIC micelle, and had a spherical structure with a 55 nm-sized diameter (58). Both... 

In order to explore the influence of glycodendrimer branches on the photophysical properties of photoactive cores, Stoddart at al. presented two carbohydrate shells, in their protected 267b and deprotected 267a forms, containing a porphyrin core. Dendrimer 267b was prepared in 16% yield from /3-D-glucopyranose building block 266 [173] and meso-tetrafunctionalized por-... 

In order to create an ideal, stand-alone, and spherically shaped NLO material that does not need to involve the complexity of incorporating an NLO chromophore in a separate polymeric matrix, multiple NLO chromophore building blocks can be placed into a dendrimer in order to construct a precise molecular architecture with predetermined chemical composition. Crosslinkable NLO dendrimer 39 is one such system exhibiting a very large optical nonlinearity and excellent thermal stability. NLO dendrimers were constmcted using a double-end funrtionalized, three-dimensional thio-phene-stilbene-based NLO chromophore as the central core and crosslinkable trifluorovinylether-containing dendrons as the exterior moieties. Spatial isolation from the dendrimer shell decreases chromophore-chromophore elertrostatic... 

---