The glass transition temperature (Tg) of layers of stereoregular poly(methyl methacrylate) (PMMA) spin-cast on silicon and aluminum surfaces has been investigated by ellipsometry. The interfacial specific interactions were highlighted and quantified by infrared reflection absorption spectroscopy. It was found that depending on PMMA tacticity, a strong correlation exists between the density of the polymer/surface interactions and the Tg of that polymer at the interface. Indeed, i-PMMA with a large density of interfacial interactions increases its Tg at the interface whereas s-PMMA with a lower value of bonded segments exhibits a Tg depression. It is suggested that a certain level of interfacial interactions associated with an increase of density of the layer will compensate for the increase of mobility resulting from a reduction of the entanglement density or a segregation of chain ends at an interface.
Summary: This article deals with recent progress including the authors' work concerning the application of block copolymers as polymeric surfactants in heterophase polymerizations. The synthesis methods for preparing block copolymers by emulsion and dispersion techniques are outlined, with emphasis on recently developed controlled free radical polymerizations in aqueous media. Specific characteristics of amphiphilic block copolymers are described, for example, micellization and emulsifying effects. A general overview of emulsion and dispersion polymerization in an aqueous and organic medium with ionic and nonionic block copolymers is presented for the preparation of electrosteric and sterically stabilized latex particles. Typical examples of microemulsion, miniemulsion, oil‐in‐oil emulsion, and micellar polymerizations are provided. Current and potential developments of so‐called “hairy latexes”, inverse‐, multiple‐, and solid emulsions, as well as of nonaqueous polymeric dispersions are also discussed.PS foam obtained by free radical polymerization of water‐in‐styrene, stabilized with a PS–PEO diblock copolymer.imagePS foam obtained by free radical polymerization of water‐in‐styrene, stabilized with a PS–PEO diblock copolymer.
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