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Responsive Vesicles from the Self‐Assembly of Crystalline‐Coil Polyferrocenylsilane‐ block ‐Poly(ethylene Oxide) Star‐Block Copolymers
Author(s) -
Schacher Felix H.,
Elbert Johannes,
Patra Sanjib K.,
Mohd Yusoff Siti F.,
Winnik Mitchell A.,
Manners Ian
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102322
Subject(s) - ethylene oxide , copolymer , polymer chemistry , materials science , polymerization , solvent , crystallinity , vesicle , polymersome , dispersity , ring opening polymerization , oxide , methanol , propylene oxide , chemical engineering , chemistry , organic chemistry , membrane , amphiphile , polymer , biochemistry , engineering , composite material , metallurgy
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.