Polyelectrolytes star-shaped

Keywords Co-assembly Cylindrical polyelectrolyte brushes Interpolyelectrolyte complexes Ionic amphiphilic block copolymers Micelles Polyelectrolytes Star-shaped polyelectrolytes... 

Scheme 12 Synthesis of star-shaped polyelectrolytes by the a arm first and b core first methods...

Abstract This review reports advances in experimental and theoretical research on interpolyelectrolyte complexes based on polyionic species of star-shaped polyelectrolytes, cylindrical polyelectrolyte brushes, and micelles of ionic amphiphilic block CO- and terpolymers. 

Plamper FA, Ruppel M, Schmalz A, Borisov O, Ballauft M, Mueller AHE (2007) Tuning the thermoresponsive properties of weak polyelectrolytes aqueous solutions of star-shaped and linear poly(N, N-dimethylaminoethyl methacrylate). Macromolecules 40 8361-8366... 

PL3 Plamper, F.A., Ruppel, M., Schmalz, A., Borisov, O., Ballauff, M., and Muller, A.H.E., Timing the thermoresponsive properties of weak polyelectrolytes Aqueous solutions of star-shaped and linear poly(A,A-dimethylaminoethyl methacrylate), Macromolecules, 40, 8361, 2007. 

During the last decade, the potential for synthesis and constmction of novel complex multicomponent self-organized IPEC-based structures has considerably increased as polyelectrolytes and polyionic species with nonlinear topology have become available. Among those are polymeric nucelles with polyelectrolyte coronas, star-shaped polyelectrolytes, and cylindrical polyelectrolyte bmshes. Polyionic species of such types themselves possess often a pronounced capability for selforganization, which is expected to be enhanced when they are incorporated into complex macromolecular structures such as IPECs. The advanced IPECs based on polyionic species with nonlinear topologies are cmisidered in Sect. 3 of this review. 

They resemble star-shaped polyelectrolytes with a large number of arms, though the number of arms in such macromolecular self-assemblies might change if the micelles are of dynamic nature, that is, if they are able to change their aggregation numbers with variations in the environmental conditions. Historically, the micelles of ionic amphiphilic diblock copolymers were the first star-like polyionic species involved in interpolyelectrolyte complexation and their IPECs have attracted considerable attention during the recent years. 

In comparison with linear-linear PEMs, multilayers formed by star polyelectrolytes usually exhibit some unique properties [30]. Such unique properties of star-star PEMs should be attributed to the topological structure of star polyelectrolytes and the resulted distinct behavior of chain interpenetration between the layers. Star-shaped polyelectrolytes usually have a more compact structure, giving rise to a more limited interpenetration in comparison with that of linear chains [30]. Thus, it is anticipated that the behavior of chain interpenetration in the growth of star-star PEMs should be different from that in the growth of linear-linear PEMs. As the arm number of star polyelectrolytes changes, the resulted steric effect can also influence the chain interpenetration. Actually, QCM-D not only can tell the extent of chain interpenetration, but also can provide which kind of polyelectrolyte will penetrate into the oppositely charged layer. 

Computer studies (both Monte Carlo and molecular dynamic simulations) have become a very powerful tool for studying the conformational and dynamic behavior of polymer chains. They can be used for testing the predictions of theoretical models concerning the equilibrium properties and moreover they provide information on dynamic characteristics, e.g., on instantaneous fluctuations of chain shapes which is important because most experimental techniques (e.g., scattering techniques) yield the ensemble-average characteristics only. Large numbers of studies have been performed on neutral chains— not only on linear ones but also on stars, combs, etc. [78-85]. The most important advances in understanding the behavior of polyelectrolytes have been made mainly thanks to computer studies. As aheady mentioned, quenched PEs have been studied both by Monte Carlo [86-89] and by molecular dynamics simulations [59, 63, 71, 73, 87, 90]. Simulation of annealed... 

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