2 research outputs found

    Diversity-Oriented Polymerization: One-Shot Synthesis of Library of Graft and Dendronized Polymers by Cu-Catalyzed Multicomponent Polymerization

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    Graft and dendronized polymers have attracted much attention in the polymer community, and there have been significant efforts to develop better synthetic methods. Herein, we report the highly efficient synthesis of graft and dendronized polymers by using Cu-catalyzed multicomponent polymerization (MCP). Based on diversity-oriented synthesis, we prepared a library of various graft and dendronized polymers from combinations of three types of monomers (mono-functionalized alkynes, bis-sulfonyl azides, and diamines/diols) that are bench stable and readily accessible. After reaction optimization, 54 samples of high-molecular-weight graft and dendronized polymers were prepared, the MCP method allowing simultaneous manipulation of the structures of both the main chains and the side chains. Moreover, because of the severe steric hindrance of the side chains, these polymers adopted extended conformations, as shown by the large shape parameter in solution. Also, the extended morphology of the single polymer chains was directly visualized by atomic force microscopy and transmission electron microscopy in the solid state. Most importantly, this diversity-oriented polymerization became possible because of highly step-economical and efficient one-step MCP, paving the way toward the easily tunable synthesis of graft and dendronized polymers

    Structure and Dynamics of Dendronized Polymer Solutions: Gaussian Coil or Macromolecular Rod?

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    We investigate the conformation of well-defined dendronized polymers (denpols) based on poly­(norborene) (PNB) and poly­(<i>endo</i>-tricycle­[4.2.2.0]­deca-3,9-diene) (PTD) backbones employing static and dynamic light scattering. Their synthesis by ring-opening metathesis polymerization (ROMP) led to fully grafted and high molecular weight denpols with narrow polydispersity. In dilute solutions, the persistence lengths were estimated by static (radius of gyration) and dynamic (translational diffusion) chain conformational properties of the denpols and were compared to their homologue precursor PNB. The conformation of denpols with a third generation side dendron conforms to a semiflexible chain with a persistence length of about 6–8 nm, virtually independent of the contour length. In the semidilute regime, the thermodynamics and cooperative diffusion of denpols resemble the behavior of the precursor solutions as described by the scaling theory of flexible polymers above the crossover concentration. The assumption of extremely high chain rigidity for this class of polymers is clearly not supported, at least for the third generation dendron
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