Microwave-assisted polymerization has been utilized to synthesize amphiphilic poly(2-ethyl-2-oxazoline-block-2-"soy alkyl"-2-oxazoline) diblock copolymers (PEtOx-PSoyOx). The amphiphilic block copolymers have been used to prepare aqueous spherical micelles consisting of a PEtOx corona and a PSoyOx core, which have been further cross-linked by UV irradiation. The morphology of these cross-linked micelles has been shown to reversibly change from spheres to short rods referred to as rice grains whenever the micelles were transferred from water into acetone, a nonselective solvent for the constituent blocks. This morphological transition has been attributed to the swelling of the slightly cross-linked PSoyOx core.

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We report on the first successful example of the preparation of triblock copolymers via a cationic ring-opening polymerization procedure. A library of 30 triblock copolymers was prepared from 2-methyl-, 2-ethyl-, 2-nonyl-, and 2-phenyl-2-oxazoline in a single-mode microwave reactor. The polymers exhibited narrow molecular weight distributions and showed only minor deviations from the targeted monomer ratio of 33:33:33. The glass-transition temperature of the triblock copolymers spanned the range from 50 to 100 °C depending on the incorporated monomers. The micellization behavior was investigated for some amphiphilic triblock copoly(2-oxazoline)s containing two hydrophilic and one hydrophobic blocks. The size of the micelles was larger when the hydrophobic block is located at one end of the triblock copoly(2-oxazoline)s, as measured by atomic force microscopy and dynamic light scattering.

The aqueous self-assembly of block copolymer systems is of major interest to prepare well-defined nanosized structures. Recently, the self-assembly of well-defined triblock and tetrablock ter-and quarterpolymers into sophisticated multicompartment micelles was reported. Inspired by these examples, the sequential one-pot synthesis of tetrablock ter-and quarterpolymers via living cationic ring-opening polymerization of 2-oxazolines was investigated under microwave irradiation, leading to well-defined tetrablock ter-and quarterpoly(2-oxazoline)s for the first time. The resulting tetrablock ter-and quarterpolymers were analyzed using both size exclusion chromatography and 1 H NMR spectroscopy, revealing their successful preparation. In addition, the surface energy of the polymers was determined to investigate the effect of block order on the surface properties. The last part of the paper discusses the aqueous self-assembly of the tetrablock ter-and quarterpolymers. Atomic force microscopy, transmission electron microscopy, and dynamic light scattering revealed the presence of spherical micellar aggregates.

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Polymers based on renewable resources are promising candidates for replacing common organic polymers, and thus, for reducing oil consumption. In this contribution we report the microwave-assisted synthesis of block and statistical copolymers from 2-ethyl-2-oxazoline and 2-“soy alkyl”-2-oxazoline via a cationic ring-opening polymerization mechanism. The synthesized copolymers were characterized by gel permeation chromatography and 1H-NMR spectroscopy. The micellization of these amphiphilic copolymers was investigated by dynamic light scattering and atomic force microscopy to examine the effect of hydrophobic block length and monomer distribution on the resulting micellar characteristics.

A new copolymer of benzo [1,2-b:4,5-b 0 ]dithiophene and 3,3 0 -bis(tridecanoxy)-5,5 0 -bithiophene was synthesized through Stille copolymerization. The bis-(3-alkoxythiophene) monomer was synthesized through a silver fluoride mediated, palladium-catalyzed cross-coupling, in which bromide functional groups were preserved instead of consumed. The copolymer has been characterized and applied in field-effect transistors, giving a hole mobility of 2 Â 10 À3 cm 2 /Vs and an on/off ratio >10 6 , with negligible hysteresis, on standard silicon substrates.