title: Characterization of Diblock Copolymer Order-Order Transitions in Semidilute Aqueous Solution Using Fluorescence Correlation Spectroscopy.
abstract: The temperature and pH-dependent diffusion of poly(glycerol monomethacrylate)-block-poly(2-hydroxypropyl methacrylate) nanoparticles prepared via polymerization-induced self-assembly in water is characterized using fluorescence correlation spectroscopy (FCS). Lowering the solution temperature or raising the solution pH induces a worm-to-sphere transition and hence an increase in diffusion coefficient by a factor of between four and eight. FCS enables morphological transitions to be monitored at relatively high copolymer concentrations (10% w/w) compared to those required for dynamic light scattering (0.1% w/w). This is important because such transitions are reversible at the former concentration, whereas they are irreversible at the latter. Furthermore, the FCS data suggest that the thermal transition takes place over a very narrow temperature range (less than 2 °C). These results demonstrate the application of FCS to characterize order-order transitions, as opposed to order-disorder transitions.
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Clarkson
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, S3 7HF, UK.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lovett
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, S3 7HF, UK.
authors.forename: Jeppe
authors.initials: J
authors.lastname: Madsen
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, S3 7HF, UK.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Geoghegan
mesh_terms: D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D011108:Polymers; D014867:Water
keywords: RAFT polymerization; fluorescence correlation spectroscopy; polymerization-induced self-assembly; spheres; worms