|344. Larin, S.V.; Pergushov, D.V.; Xu, Y.; Darinskii, A.A.; Zezin, A.B.; Müller, A.H.E.; Borisov, O.V.: Nano-patterned structures in cylindrical polyelectrolyte brushes assembled with oppositely charged polyions, Soft Matter 5, 4938 (2009) -- DOI: 10.1039/b913944c|
We demonstrate that the electrostatically driven association of cylindrical polyelectrolyte brushes (CPBs) with oppositely charged linear polyelectrolytes (PEs) in dilute aqueous solution gives rise to well-defined and colloidaly stable (not undergoing secondary aggregation with time) polymeric nano-assemblies representing novel water-soluble interpolyelectrolyte complexes (IPECs). Each complex particle comprises a single host CPB whose charge is undercompensated by the guest PE chains. Molecular dynamics (MD) simulations were used to probe the structural organization of these nano-assemblies. We find that they spontaneously adopt the shape of a necklace of complex coacervate pearls which comprise charged monomer units of CPB and those of the guest PEs in approximately stoichiometric (1:1) ratio. Each complex coacervate pearl is decorated by a star-like PE corona formed by the branches of the CPB not involved in the interpolyelectrolyte complexation. Repulsive interactions between these coronas stabilize the periodic intra-molecular structure and assure aggregative stability of the IPEC derived from the single CPB. AFM images of the complex particles deposited on mica unambiguously support their pearl-necklace structural organization. Our work theoretically predicts and experimentally confirms a possibility to tune the periodicity of onedimensional intramolecular nano-patterned structures on will by a variation of the base-molar ratio between the oppositely charged macromolecular building blocks incorporated in the polymeric nanoassembly, that is, by a variation of the stoichiometry of the IPECs.
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