Synthesis by nitroxide-mediated aqueous dispersion polymerization, characterization, and physical core-crosslinking of pH- and thermoresponsive dynamic diblock copolymer micelles

Guillaume Delaittre, Maud Save, Marianne Gaborieau, Patrice Castignolles, Jutta Rieger, Bernadette Charleux

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    46 Citations (Scopus)

    Abstract

    Diblock copolymers consisting of a poly(acrylic acid) (PAA) segment and a LCST-type poly(N,N-diethylacrylamide) (PDEAAm) block were obtained by nitroxide-mediated polymerization in aqueous dispersion using a water-soluble macroalkoxyamine. The influence of several parameters on the polymerization (temperature, initial free nitroxide or macroalkoxyamine concentrations, and solids content) was evaluated in terms of kinetics, macromolecular control, and colloidal features. As determined by dynamic light scattering (DLS), stable dispersions of monodisperse particles could be obtained for solids content as high as 39 wt% without the need for any additional surfactant via a polymerization-induced self-assembly mechanism. Rendered possible by the use of a controlled/living polymerization process, the effective semi-batch incorporation of hydrophobic units (styrene) in the growing chains during the polymerization allowed the formation of physically crosslinked nanogels. The pH and temperature sensitivity were proved by means of DLS and high-sensitivity differential scanning calorimetry (HSDSC) measurements. Due to the formation of aggregates observed by size-exclusion chromatography in N,N-dimethylformamide, accurate molar masses could not be determined directly but deconvoluted hydrodynamic volume distributions suggested a good control of the polymerization.
    Original languageEnglish
    Pages (from-to)1526-1538
    Number of pages13
    JournalPolymer Chemistry
    Volume3
    Issue number6
    DOIs
    Publication statusPublished - 2012

    Keywords

    • diblock copolymers
    • gel permeation chromatography
    • nanogels
    • polymerization

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