title: Nanofibrillar micelles and entrapped vesicles from biodegradable block copolymer/polyelectrolyte complexes in aqueous media.
abstract: Here we report a viable route to fibrillar micelles and entrapped vesicles in aqueous solutions. Nanofibrillar micelles and entrapped vesicles were prepared from complexes of a biodegradable block copolymer poly(ethylene oxide)-block-poly(lactide) (PEO-b-PLA) and a polyelectrolyte poly(acrylic acid) (PAA) in aqueous media and directly visualized using cryogenic transmission electron microscopy (cryo-TEM). The self-assembly and the morphological changes in the complexes were induced by the addition of PAA/water solution into the PEO-b-PLA in tetrahydrofuran followed by dialysis against water. A variety of morphologies including spherical wormlike and fibrillar micelles, and both unilamellar and entrapped vesicles, were observed, depending on the composition, complementary binding sites of PAA and PEO, and the change in the interfacial energy. Increasing the water content in each [AA]/[EO] ratio led to a morphological transition from spheres to vesicles, displaying both the composition- and dilution-dependent micellar-to-vesicular morphological transitions.
authors.affiliation: Polymers Research Group, Institute for Frontier Materials, Deakin University, Locked Bag 2000, Geelong, Victoria 3220, Australia.
authors.forename: Nisa V
authors.initials: NV
authors.lastname: Salim
authors.forename: Nishar
authors.initials: N
authors.lastname: Hameed
authors.forename: Tracey L
authors.initials: TL
authors.lastname: Hanley
authors.forename: Lynne J
authors.initials: LJ
authors.lastname: Waddington
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Hartley
authors.forename: Qipeng
authors.initials: Q
authors.lastname: Guo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D004852:Epoxy Compounds; D008823:Micelles; C402662:PEO-poly(lactide); D011091:Polyesters; D012996:Solutions; D014867:Water; C006903:carbopol 940