title: Responsive vesicles from the self-assembly of crystalline-coil polyferrocenylsilane-block-poly(ethylene oxide) star-block copolymers.
abstract: We demonstrate the synthesis and characterization of star-shaped crystalline-coil block copolymers with four arms consisting of an inner block of poly(ethylene oxide) and an outer semicrystalline compartment of poly(ferrocenyldimethylsilane), [PEO(50) -b-PFDMS(35)](4). The materials were synthesized by transition-metal-catalyzed ring-opening polymerization of dimethylsila[1]ferrocenophane in the presence of silane-functionalized four-arm PEO stars as macroinitiators and they exhibited a moderate polydispersity (PDI≅1.4). Self-assembly in mixtures of THF and different alcohols as selective solvents for the PEO block resulted in the formation of semicrystalline vesicles (ethanol, 1-butanol) or large, rather ill-defined, spherical structures (methanol). Further, both the rate of addition of the selective co-solvent and the overall solvent/non-solvent ratio drastically affected the size and stability of the self-assembled particles. We could also show that a photoacid generator, as a model for an active substance, can be encapsulated and the UV-induced generation of HCl resulted in a straightforward degradation of the organometallic vesicles.
authors.affiliation: Institute of Organic and Macromolecular Chemistry and Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Humboldtstrasse 10, 07743 Jena, Germany. felix.schacher@uni-jena.de
authors.forename: Felix H
authors.initials: FH
authors.lastname: Schacher
authors.forename: Johannes
authors.initials: J
authors.lastname: Elbert
authors.forename: Sanjib K
authors.initials: SK
authors.lastname: Patra
authors.forename: Siti F Mohd
authors.initials: SF
authors.lastname: Yusoff
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Winnik
authors.forename: Ian
authors.initials: I
authors.lastname: Manners
mesh_terms: D003460:Crystallization; D005296:Ferrous Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D058105:Polymerization; D012821:Silanes / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D012821:Silanes; C554070:poly(ferrocenylsilane); D011092:Polyethylene Glycols