Molecular architecture topology

Kuo, C. M. Clarson, S. J. Semiyen, J. A., Studies of Cyclic and Linear Poly(dimethylsiloxanes) 31. Effect of Molecular Architecture/Topology on Blends of Poly(methylphenylsiloxane) and Poly(dimethylsiloxane). Polymer 1994, 35,4623-4626. 

Kuo, C.M., Clarson, S.J., and Semiyen, J.A. (1994) Studies of cyclic and linear poly(dimethylsiloxane)s 31. Effect of molecular architecture/topology on blends of poly(methylphenylsiloxane) and polyfdimethylsiloxane). Polymer, 35,4623 26. 

Tailor-made macromolecules have come into the focus of polymer science to overcome the challenges of a number of complex applications from the nano to the macro scale. Materials scientists have been designing and synthesizing tailor-made macromolecules specific for each application. These materials are composed of different monomeric units, chemical functionalities, and topologies. The challenge has been to control precisely the position of the functionality on the polymer, to determine the necessary ratio of monomeric units, as well as to understand the effect of the molecular architecture on the material performance. 

Isoreticular structures a series of molecular architectures with identical network topologies but with different functionalities and dimensions... 

As in binary surfactant-water systems considered previously, two constraints on the geometry of the surfactant interface are active a local constraint, which is due to the surfactant molecular architecture, and a global constraint, set by the composition. These constraints alone are sufficient to determine the microstructure of the microemulsion. They imply that the expected microstructure must vary continuously as a function of the composition of tile microemulsion. Calculations show - and small-angle X-ray and neutron scattering studies confirm - that the DDAB/water/alkane microemulsions consist of a complex network of water tubes within the hydrocarbon matrix. As water is added to the mixture, the Gaussian curvature - and topology -decreases [41]. Thus the connectivity of the water networks drops (Fig. 4.20). 

FIGURE 2 The class, architecture, topology, homology (CATH) classification of a protein. SOURCE Department of Biochemistry and Molecular Biology, University College, London. This figure can be viewed in color at . 

The most popular click reaction is Huisgen 1,3-dipolar cycloaddition of azides to alkynes applicable to a very wide range of macro molecular architecture. It has been employed for the preparation of various polymer topologies including linear, star, hyperbranched, and H-shaped polymers. The general approach is illustrated in Scheme 70 for the preparation of linear block copolymer of EO with MMA and St. Anionically prepared PEO was functionalized with azide and used in copper-catalyzed click reaction with PMMA or PSt with alkyne moiety synthesized by using alkyne-flinctional ATRP initiator. It should be noted that alkyne functionality of hetero-functional ATRP initiator was protected with a trimethylsilyl... 

Three topology-varied rod-coil block copolymers (27), comprising the same OPE rod components and the same poly (2-(carbazoI-9-yI)ethyI methacrylate) as the coil components, but with different molecular architectures, linear, T-shaped, and cross-shaped, were prepared. These copolymers have dissimilar p-p interactions of the OPE rods and are dependent on the molecular architecture. This leads to the discrepant tendencies of creating aggregates. ... 

In 1997, Jeong and Kim et al. reported biodegradable IP systems using a triblock copolymer of PEG and PLLA, PEG-h-PLLA-h-PEG [32]. After this achievement, many block copolymers with combinations of PEGs and aliphatic polyesters were reported [45-47] with various molecular architectures. Linear block, star-shaped block, and graft topologies... 

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