Open AccessPerfluorocarbon‐loaded shell crosslinked knedel‐like nanoparticles: Lessons regarding polymer mobility and self‐assembly
Author(s) -
Nyström Andreas M.,
Bartels Jeremy W.,
Du Wenjun,
Wooley Karen L.
Publication year - 2009
Publication title -
journal of polymer science part a: polymer chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.768
H-Index - 152
eISSN - 1099-0518
pISSN - 0887-624X
DOI - 10.1002/pola.23184
Subject(s) - copolymer , polymer chemistry , dispersity , micelle , ethylene glycol , chain transfer , materials science , monomer , polymer , polymerization , styrene , butyl acrylate , amphiphile , acrylate , side chain , self assembly , nanoparticle , chemical engineering , chemistry , radical polymerization , organic chemistry , aqueous solution , nanotechnology , engineering , composite material
Reversible addition‐fragmentation chain transfer polymerization was employed to synthesize a set of copolymers of styrene (PS) and 2,3,4,5,6‐pentafluorostyrene (PPFS), as well as block copolymers with tert ‐butyl acrylate (P t BA)‐ b ‐PS‐ co ‐PPFS, with control over molecular weight and polydispersity. It was found that the copolymerization of styrene and PFS allowed for the preparation of gradient copolymers with opposite levels of monomer consumption, depending on the feed ratio. Conversion to amphiphilic block copolymers, PAA‐ b ‐(PS‐ co ‐PPFS), by removing the protecting groups was followed by fitting with monomethoxy poly(ethylene glycol) chains. Solution‐state assembly and intramicellar crosslinking afforded shell crosslinked knedel‐like (SCK) block copolymer nanoparticles. These fluorinated nanoparticles (ca. 20 nm diameters) were studied as potential magnetic resonance imaging (MRI) contrast agents based on the 19 F‐nuclei; however, it was found that packaging of the hydrophobic fluorinated polymers into the core domain restricted the mobility of the chains and prohibited 19 F NMR spectroscopy when the particles were dispersed in water without an organic cosolvent. Packing of perflouro‐15‐crown‐5‐ether (PFCE) into the polymer micelle was demonstrated with good uptake efficiency; however, it was necessary to swell the core with a good solvent (DMSO) to increase the mobility and observe the 19 F NMR signal of the PFCE. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1023–1037, 2009