Interpolyelectrolyte complex micelles

Interpolyelectrolyte complexes Micelles Nanostructures Polyelectrolytes Supramolecular chemistry... 

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. 

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

Another example of multicompartment micellar IPECs is the macromolec-ular co-assembly of the triblock terpolymer poly(Af,Af-dimethylacrylamide)- /ocfc-poly(A-acryloylalanine)-fetocA -poly(iV-isopropylacrylamide) or the diblock terpolymer poly(A,A-dimethylacrylamide)-fe/(9cA -poly(Ai-isopropylacrylamide)-stat-(A-acryloylvaline), interacting in aqueous media with poly(ar-vinylbenzyl) trimethylammonium chloride (PVBTAC) [76, 77], The authors demonstrated that interpolyelectrolyte complexation of such assemblies formed with PVBTAC within specific pH and temperature ranges makes them stable with respect to the disassembly induced by cooling below critical micellization temperatures. 

Schacher E, Betthausen E, Walther A, Schmalz A, Pergushov D, Muller A (2009) Interpolyelectrolyte complexes of dynamic multicompartment micells. ACS Nano 3 2095... 

Pergushov, D.V., Remizova, E.V., Gradzielski, M., Lindner, P., Feldthusen, J., Zezin, A.B., Muller, A.H.E. and Kabanov, V.A. (2004) Micelles of polyisobutylene-block-poly(methacrylic acid) diblock copolymers and their water-soluble interpolyelectrolyte complexes formed with quaternized poly(4 vinylpyridine). Polymer, 45, 367-378. 

Block copolymers with poly(MA-St) block formed micelles by hydrophobic self-association or by interpolyelectrolyte complexation. Thus, poly(N-isopropylacrylamide)-block-poly(MA-St)-block-polystirene self-assembles into micelles that showed a pH- and thermo-responsive drug release behavior [222]. Interpolyelecrolyte complex micelles with potential use as drug delivery systems were obtained with poly(N-vinylpyrrolidone)-block-poly(MA-St) as polyanion and chitosan or poly(N-vinylpyrrolidone)-block-poly(N,N-dimethylaminoethyl methacrylate) as polycation [223,224]. 

Further progress in the field of IPECs has been associated with involvement of more complex polyionic architectures, such as branched ionic (co)polymers (polyelectrolyte stars and cylindrical polyelectrolyte brushes) as well as self-assemblies of linear ionic diblock copolymers (polymeric micelles) (Fig. 6a-c), into interpolyelectrolyte complexation. Synthesis of well-defined polymeric architectures with nonlinear topology has become possible only recently due to considerable developments in living and controlled polymerizations. In this section, we briefly... 

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. 

A cleavable, temperature-responsive polymeric cross-linker was utilized by Xu and cowoikers [111] to stabilize micelles from PEO-b-PAPMA-b-poly((Af,Af-diisopropylamino)ethyl methacrylate) triblock copolymer. The PNIPAm cross-linker contained activated ester end groups that were reacted with the primary amines on the PAPMA middle block. The trithiocarbonate moiety located at the middle of PNIPAm cross-linker could then be degraded by aminolysis to break the cross-links. Temperature-responsive micelles and vesicles from diblock and triblock copolymers were shell cross-linked via interpolyelectrolyte complexation [108, 112]. The cross-links formed by the electrostatic interactions of oppositely charged polyelectrolytes could be disrupted by the addition of SME. 

Lokitz BS, York AW, Stempka JE, Treat ND, Li Y, Jarrett WL, McCormick CL. Aqueous RAFT synthesis of miceUe-forming amphiphilic block copolymers containing N-acryloylvahne. Dual mode, temperature/pH responsiveness, and locking of micelle structure through interpolyelectrolyte complexation. Macromolecules 2007 40 6473-6480. 

Lokitz BS, Convertine AJ, Ezell RG, Heidenreich A, Li Y, McCormick CL. Responsive nanoassemblies via interpolyelectrolyte complexation of amphiphilic block copolymer micelles. Macromolecules 2006 39 8594-8602. 

Water-soluble interpolyelectrolyte complexes (IPECs) can be prepared by complexation of amphiphihc block copolymers, which comprise a hydrophobic block and an ionic or hydrophilic nonionic block [81,82]. Double hydrophilic block copolymers having an ionic block and a nonionic one can be prepared for IPECs even in 1 1 charge-to-charge ratio of the polymeric components in aqueous solution [81]. IPECs normally have a core/corona structure and are often referred to as polyion complex micelles, complex coacervate micelles, or block ionomer complexes [83,84]. 

Pergushov DV et al. Micelles of polyisobutylene-block-poly(methacrylic acid) diblock copolymers and their water-soluble interpolyelectrolyte complexes formed with quat-emized poly(4-vinylpyridine). Polymer 2004 45(2) 367-378. 

Recent progress in novel micellar structures, including micelles containing exotic blocks such as natural or synthetic polypeptides and metal-containing segments, micelles from ABC triblock copolymers, Janus micelles and other noncentrosymmetric micelles, micelles based on interpolyelectrolyte or other noncovalent complexes, and metallosupramolecular micelles, will be discussed in Sect. 7. 

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