Dendritic dendronized polymers

Hyperbranched and dendronized polymers such as 40, 41, and 42 have also been synthesized using the transition metal coupling strategies in recent years.32 These polymers are fundamentally different from those traditional linear polymers. They possess dendritic arms within die polymer or along the polymer backbone. It is believed that they possess interesting properties and have potential applications in many fields such as nanotechnology and catalysis ... 

In one of several important studies on dendronized polymers [4c, 4d]. Schluter and coworkers explored the stiffening of polystyrene chains through the incorporation of Frechet-type dendrons as side chains [28, 29]. While the G-l and G-2 dendrons were not sufficiently bulky to effectively stiffen the polystyrene chain, the G-3 dendron provides enough steric bulk to force the hybrid polymer into adopting a cylindrical shape in solution [28b], In a complementary study, Neubert and Schluter demonstrated that adding charges to the dendritic wedges leads to an expansion of the chains of the hybrid copolymer in aqueous solution [29],... 

Recent seminal work reported by Percec et al. [45-47] has shown that either spheroidal or cylindrically shaped dendronized polymers may be obtained by the polymerization of a dendronized macromonomer . The degree of polymerization of these monomers determines the ultimate shape which appears to demonstrate the quasi-equivalence of dendritic coats . 

Its design versatility, as generic dendrons may be prepared to be used later as building blocks in conjunction with other reactive molecules, or coupled to a multifunctional core to afford functional dendrimers, dendritic-linear hybrids, dendronized polymers, etc. This may be a particularly significant advantage if the coupled reactive or core molecule is itself sensitive to the reaction conditions used in the multiple steps of the iterative synthesis of a dendrimer. 

The II-A isotherms suggest an orientation that aligns the long axis of the polymer rod in the plane of the interface with the EO chains of the hydrophilic dendrons extended into the water layer and the hydrophobic dendrons pointed upward from the surface. The stability of the dendronized polymers likely arises from the balance between the polar and nonpolar regions exposed at the surface of the polymeric cylinder (Bo et al. 1999 Schluter and Rabe 2000). Ariga and colleagues (2004) constmcted a series of spider web dendritic amphiphiles that project hydrophilic Lys-Lys-Glu tripeptides and hydrophobic chains at each generational level (Fig. 11.42). 

Dendronized polymers are a class of polymers produced by the combination of linear polymers and dendritic molecules as side chain pendant moieties [67-69],... 

Abstract Enantioselection in a stoichiometric or catalytic reaction is governed by small increments of free enthalpy of activation, and such transformations are thus in principle suited to assessing dendrimer effects which result from the immobilization of molecular catalysts. Chiral dendrimer catalysts, which possess a high level of structural regularity, molecular monodispersity and well-defined catalytic sites, have been generated either by attachment of achiral complexes to chiral dendrimer structures or by immobilization of chiral catalysts to non-chiral dendrimers. As monodispersed macromolecular supports they provide ideal model systems for less regularly structured but commercially more viable supports such as hyperbranched polymers, and have been successfully employed in continuous-flow membrane reactors. The combination of an efficient control over the environment of the active sites of multi-functional catalysts and their immobilization on an insoluble macromolecular support has resulted in the synthesis of catalytic dendronized polymers. In these, the catalysts are attached in a well-defined way to the dendritic sections, thus ensuring a well-defined microenvironment which is similar to that of the soluble molecular species or at least closely related to the dendrimer catalysts themselves. 

Dendritic layer copolymers have also been prepared via the hypercore approach,87 and by divergent growth from the periphery of convergently prepared dendrimers,446 or dendronized polymers.398 This layered dendritic architecture has been used by a number of groups to probe the nature of chirality. 

Dendronized polymers, i.e., polymers with dendritic side chains, are currently under intense investigation with respect to various applications, including the synthesis of hierarchically structured... 

Scheme 30.22 General scheme for the synthesis of dendronized polymers prepared via CuAAC click coupling of benzyl ether dendritic azides onto the backbone of poly(vinylacetylene). Dendronized polymers...

These two attributes - responsivity and the loadable interior - of the dendronized polymers can, in principle, be exploited to create smart delivery vehicles in which the release of guest molecules can be triggered by conformational changes of the responsive dendritic envelope. Additionally, unlike conventional polymers. 

Dendronized polymers, a type of dendritic molecule, exhibit properties not only from the dendron they possess - high functionality and regularity - but also from the polymer segments that are connected to dendrons or used to coimect several dendrons. Many different architectures of dendronized polymers can be prepared, depending on the t5q)e of polymer used, where the dendrons are attached, and how many are introduced. These architectures include, among others, dendron-coil, dendron-rod, dendron-rod-coil, and dendron-coil-dendron. The dendron-mediated assembly of dendronized polymers has been reviewed by Rosen et al7 ... 

As a second example cylindrical brush polymers, often called bottle brushes, are described (Sect. 3). Cylindrical brush polymers usually consist of a flexible main chain, densely grafted by flexible, stiff or dendritically branched side chains. The latter are known as dendronized polymers and have been fi equently investigated by both theory and experiment. In the present review, we focus on brush polymers with linear side chains. 

After the initial step, where a maltose dendron was obtained as ihe starting material, the dendritic surfactant polymers were then synthesized via a two-step method. 

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