Complex, macromolecular architecture

Synthesis of Copolymers with Complex Macromolecular Architectures... 

I/III. Complex Macromolecular Architectures A. Star and Graft Polymers... 

The reduced concentration of radical centers at the chain ends of living radical polymerizations opens up a number of possibilities in the synthesis of complex macromolecular architectures due to the very low... 

Stogiou, M. Kapetanaki, C. latrou, H. Examination of the universality of the calibration curve of size exclusion chromatography by using polymers having complex macromolecular architectures. Int. J. Polym. Anal. Charact. 2002, 7, 273-283. 

The design of complex macromolecular architectures has become a particular focus in polymer science. Some of these architectures possess unique properties, which makes them interesting candidates for specialty applications in nanostructured and biomedical materials such as block and branched copolymers. In particular the advent of controlled radical polymerization techniques provided convenient synthetic pathways to realize polymer architectures (1-3). 

Hence, the perfonned within the framewoik of fractal approach analysis of behavior of polystirene, modified by Dendron s, in diluted solutions gave the same conclusions, as the analysis within the fiamewoik of classical approaches. The main distinction of the indicated approaches is the fact, that the structural model, allowing to describe quantitatively macromolecules structural state and conformation, was placed in the fractal approach base. Other characteristics (gyration radius, Kuhn segment length and so on) are the function of the indicated structural state of a macromolecule. The fractal analysis methods, used for the description of linear flexible-chain polymers behavior, can be applied successfiilly also in case of polymers with more complex macromolecular architecture. 

Recent advances in polymer chemistry, in particular, in controlled radical polymerization, have enabled the synthesis of complex macromolecular architectures with controlled topology, which comprise chemically different (functional) blocks of controlled length in well-defined positions. Block co- and terpolymers, molecular and colloidal polymer brushes, and star-like polymers present just a few typical examples. Furthermore, miktoarm stars, core-shell stars and molecular brushes, etc. exemplify structures where chemical and topological complexity are combined in one macromolecule. 

Thus, in addition to the well-received applications of NMR for structure characterization, there are additional physicochemical aspects of complex macromolecular architectures, biohybrid structures, and aggregates and complexes, which can be investigated using NMR. In particular the measurement of displacements based on PEG NMR for either measuring diffusion or the electrophoretic mobility offers additional information on the size and charge of these various macromolecular architectures and compositions. The inherently available chemical shift information allows the identification of the moving species, which is important in multicomponent systems or when the formation of complexes is studied. 

Complex Macromolecular Architectures From Poly(allg lene H-Phosphonate)s... 

Poly(alkylene H-phosphonate)s represent a wide range of biodegradable polymers with repeating phosphoester linkages in the backbone and have been inserted in a variety of complex macromolecular architectures (Scheme 6.17). 

Kuo, C.-C., Liu, C.-L., and Chen, W.-C. (2011) Morphologies and photophysical properties of conjugated rod-coil block copolymers, in Complex Macromolecular Architecture Synthesis, Characterization, and Self-Assembly, 1st edn (eds A. Hirao,... 

T. Satoh and T. Kakuchi, Hyperbranched Glyco-Conjugated Pol5mers , in Complex Macromolecular Architectures Synthesis, Characterization, and Self-Assembly, eds. N. Hadjichristidis, A. Hirao, Y. Tezuka and F. Du Prez, John Wiley Sons (Asia) Pte. Ltd. Singapore, Singapore, 2011, p. 195. 

Furthermore, the integration of ATRP with other polymerisation methods, such as ringopening polymerisation, cationic and anionic polymerisations, has permitted the preparation of novel complex macromolecular architectures [20]. 

Hedrick, J.L., et al., 2002. Application of complex macromolecular architectures for advanced microelectronic materials. Chemistry — A European Journal 8 (15), 3308—3319. 

While end-functional polymers are clearly important industrial products for materials synthesis, they are also interesting from an academic point of view. Many complex macromolecular architectures can be realized from end-functional polymeric starting materials. Two mono-telechelic polymers can, for example, be joined to form a diblock copolymer, or several such polymers can be joined to form star-like polymers. Mono-telechelic polymers can also be attached to a linear, multifunctional polymer to yield graft copolymers. Depending on the functional end group, such polymers can attach to macroscopic or nanoparticle surfaces or form conjugates with bio-oligomers [5] or biomacromolecules [6]. 

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