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Micellization of PS‐PMMA Diblock Copolymers in an Ionic Liquid
Author(s) -
Simone Peter M.,
Lodge Timothy P.
Publication year - 2007
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200600392
Subject(s) - copolymer , micelle , ionic liquid , hexafluorophosphate , polystyrene , transmission electron microscopy , materials science , polymer chemistry , dynamic light scattering , solvent , methyl methacrylate , volume fraction , acetone , chemical engineering , chemistry , organic chemistry , polymer , aqueous solution , composite material , nanotechnology , nanoparticle , catalysis , engineering
Three polystyrene‐ block ‐poly(methyl methacrylate) (PS‐PMMA) block copolymers with varying molecular content have been shown to form micelles when dissolved in the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIM PF 6 ). The micellar structure was studied via cryogenic transmission electron microscopy and dynamic light scattering, and a morphological transition from spherical to cylindrical micelles was observed upon reduction of the PMMA volume fraction. The possibility of frozen micellar morphology was considered, due to the solution preparation method and high glass transition temperature ( T g ) of the PS blocks that form the micellar cores. By comparison of the behavior of a 100 kDa PMMA homopolymer dissolved in both BMIM PF 6 and a known good solvent, acetone, it was determined that BMIM PF 6 behaves as a good solvent for PMMA. It was also observed that extended exposure to the electron beam during cryogenic transmission electron microscopy could damage the copolymer micelles and result in a reversal of contrast.