A combination of anionic and nitroxide‐mediated radical polymerizations (dual initiator) was employed for the synthesis of poly(n‐hexyl isocyanate‐b‐N‐vinylpyrrolidone) (PHIC‐b‐PNVP) block copolymers. The samples were characterized with a size exclusion chromatograph equipped with refractive‐index and light scattering detectors as well as 1H NMR spectroscopy. Relatively good control over the molecular weights was achieved. However, rather broad molecular weight distributions were obtained. The micellar properties of the PHIC‐b‐PNVP block copolymers were studied in water, which is a selective solvent for the poly(N‐vinylpyrrolidone) blocks. Static and dynamic light scattering revealed the presence of equilibrium between the micelles and clusters. The clusters partially deaggregated with increasing temperature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5719–5728, 2006

Anionic polymerization high‐vacuum techniques and appropriate multifunctional initiators/additives were employed for the synthesis of novel star structures of poly(n‐hexyl isocyanate) (PHIC). A new trifunctional initiator prepared by the reaction of tris(4‐isocyanatophenyl)methane with benzyl sodium was used for the synthesis of three‐arm star PHIC. Divinyl benzene and the core‐first or the arm‐first/core‐first (in‐out) approach were utilized for the synthesis of multiarm star homopolymers, (PHIC)n, star‐block copolymers, (PHIC‐b‐PI)n, and miktoarm star copolymers, (PS)n(PHIC)n, where PS is polystyrene. The molecular characteristics obtained by size‐exclusion chromatography, equipped with refractive index and two‐angle light scattering detectors, nuclear magnetic resonance, spectroscopy, and dilute solution viscometry showed that well‐defined structures were synthesized in this study. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2387–2399, 2007

Several monofunctional initiators, such as s-BuLi, 1,1-diphenyl-4-methylpentyl lithium (DPMPL), benzyl potassium (BzK), triphenylmethyl sodium (trityl sodium, TrNa) and benzyl sodium (BzNa) were tested and evaluated for the polymerization of n-hexyl isocyanate (HIC) in THF at À98 8C. The polymerizations were conducted either without or with additives, such as LiBPh 4 , NaBPh 4 , and crown ether 18C6. The products were characterized by size exclusion chromatography (SEC), membrane osmometry (MO), and 1 H NMR spectroscopy. The best results regarding polymerization yield, molecular weight distribution, and agreement between the stoichiometric and the experimentally observed molecular weight were obtained by the initiating system BzNa/NaBPh 4 in a molar ratio 1/10. By using BzNa/NaBPh 4 system, well-defined block copolymers of HIC with styrene or isoprene were synthesized for the first time. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3533-3542, 2005

Block copolymers have attracted significant scientific and economic interest over the last decades due to their ability to self-assemble into ordered structures both in bulk and in selective solvents. In this work, the self-assembly behaviour of both linear (diblocks, triblocks and pentablocks) and nonlinear (miktoarm stars and a block-graft) copolymers based on poly(n-hexyl isocyanate), PHIC, were studied in selective solvents such as n-heptane and n-dodecane. A variety of experimental techniques, namely static and dynamic light scattering, dilute solution viscometry and atomic force microscopy, were employed to study the micellar structural parameters (e.g., aggregation number, overall micellar size and shape, and core and shell dimensions). The effect of the macromolecular architecture, the molecular weight and the copolymer composition on the self-assembly behaviour was studied. Spherical micelles in equilibrium with clusters were obtained from the block copolymers. Thermally stable, uniform and spherical aggregates were found from the triblock copolymers. The poly(n-hexyl isocyanate)-b-polyisoprene-b-poly(n-hexyl isocyanate),-HIH copolymers tend to adopt closed loop conformation, leading to more elongated cylindrical-type structures upon increasing the concentration. Clustering effects were also reported in the case of the pentablock terpolymers. The topology of the blocks plays an important role, since the poly(n-hexyl isocyanate)-b-polystyrene-b-polyisoprene-b-polystyrene-b-poly(n-hexyl isocyanate), HSISH terpolymer shows intermicellar fusion of spherical micelles, leading to the formation of extended networks. The formation of spherical micelles in equilibrium with clusters was obvious in the case of the miktoarm stars, whereas the block-graft copolymer shows the existence of mainly unimolecular micelles.