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We describe the synthesis and solution morphologies of poly(vinyl phenol-b-styrene) (PVPh-b-PS) micelles and the effects that changing the copolymer composition and concentration have on self-assembly structures of PVPh-b-PS in acetone (a good solvent for PVPh). These PVPh-b-PS copolymers aggregated into spherical, rod-like, and vesicular morphologies. The transformations of the PVPh-b-PS block copolymer micelles in acetone depended on a number of parameters, including the relative block lengths, their concentrations, and the degree of self-association through hydrogen bonding of the coronal PVPh chains. We also investigated the morphologies of the micelles formed from acetone solutions of poly(4-tert-butoxystyrene-b-styrene) (PtBOS-b-PS) copolymers having the same degree of polymerization as the precursor of PVPh-b-PS copolymer before hydrolysis reaction. Our results indicate that the micelles formed from PVPh-b-PS copolymers in acetone were more complicated than those prepared from PtBOS-b-PS copolymers in acetone because hydrogen bonding occurs in the micelle corona of the PVPh block. Finally, we also discussed the morphology transition when the self-association hydrogen bonding of PVPh block was destroyed by adding proton acceptor poly(4-vinylpyridine) (P4VP).

A series of poly(vinylphenol-b-vinylpyridine) (PVPh-b-P4VP) block copolymers were prepared through anionic polymerizations of 4-tert-butoxystyrene with 4-vinylpyridine followed by subsequent selective hydrolysis of the 4-tert-butoxystyrene protective groups. Infrared spectrum analysis suggests that this block copolymer possesses strong hydrogen-bonding interaction between the hydroxyl group of PVPh and the pyridine group of P4VP. DSC analyses indicate that these PVPh-b-P4VP copolymers always have higher glass transition temperatures than the corresponding PVPh/P4VP miscible blends obtained from DMF solution. However, the thermal behavior of PVPh-b-P4VP diblock copolymer shows a similar Tg value with the PVPh/P4VP blend complex obtained from methanol solution at a 1:1 (PVPh:P4VP) molar ratio. We proposed that the polymer chain behavior of the PVPh/P4VP blend from DMF solution is separated coils. However, by increasing the hydrogen bonding for PVPh-b-P4VP diblock copolymer, a polymer complex aggregate is proposed, which is similar to the PVPh/ P4VP blend complex from methanol solution. The spin-lattice relaxation time in the rotating frame ( T 1F H ) based on solid-state NMR analysis is able to provide positive evidence that the polymer complex aggregate in the diblock copolymer has a shorter T1F H value than the separated coils in the miscible blend.

We have synthesized rod-coil diblock PPQ-b-PMMA copolymers by using the versatile atom-transfer radical polymerization method and have characterized them by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The methyl ketone-terminated rod-coil diblock PMMA copolymer has a higher value of Tg, because of its syndiotactic-like structure, and a higher decomposition temperature than does the PMMA homopolymer. The presence of the PPQ block tends to retard the early decomposition of the PMMA chain. A regularly porous, honeycomb-structured film was prepared from the dichloromethane solution of the diblock copolymers under a flow of moist air. The diameters of the spherical pores can be controlled in the range from 0.8 to 3 m mb y modifying both the rod-coil copolymers’ relative molecular weights and the casting conditions. The wall thickness of the film is varied linearly with the relative molecular mass (Mr). q 2005 Elsevier Ltd. All rights reserved.

We have synthesized a series of block copolymers of poly(2,6-dimethyl-1,4-phenylene oxide) and polystyrene (PPO-b-PS copolymer) by atom transfer radical polymerization. The PS content in these copolymer systems was determined by using infrared spectroscopy, thermal gravimetric analysis, and solution and solid-state NMR spectroscopy; good correlations exist between these characterization methods. DSC analyses indicated that the PPO-b-PS copolymers have higher glass transition temperatures than do their corresponding PPO/PS blends. Our FTIR and solid-state NMR spectroscopic analyses suggest that the PPO-b-PS copolymers possess stronger specific interactions that are responsible for the observed relatively higher values of Tg. We found one single dynamic relaxation from the dynamic mechanical analysis, which implies dynamic homogeneity exists in the PPO-b-PS copolymer; this result is consistent with the one single proton spin‐lattice relaxation time observed in the rotating frame [T1r(H)] during solid state NMR spectroscopic analysis. In addition, the 2D FTIR spectroscopy reveals evidence for the stronger interactions between segments of PPO and PS through the formation of p-cation complexes. q 2005 Elsevier Ltd. All rights reserved.

A nanoporous polyhedral oligomeric silisesquioxane (POSS) containing eight epoxy functional groups [octakis(dimethylsiloxypropylglycidyl ether)silsesquioxane, OG] reacts with meta-phenylenediamine (mPDA) to form epoxy resin network with nanostructures. The glass transition temperature (Tg) of the cured OG/mPDA product is significantly higher than that of the diglycidyl ether of bisphenol A (DGEBA) cured with mPDA (DGEBA/mPDA) material due to the presence of the POSS cages that is able to effectively hinder the motion of the network junctions. The cured OG/mPDA product inherently possesses higher thermal stability than the cured DGEBA/mPDA product based on higher maximum decomposition rate temperature, and higher char yield of the former. However, the existence of large fraction of the unreacted amine groups causes lower initial decomposition temperature of the OG/mPDA because it tends to decompose or volatilize on heating at relatively low temperature. The dielectric constant of the OG/mPDA material (2.31) is substantially lower than that of the DGEBA/mPDA (3.51) as a consequence the presence of nanoporous POSS cubes in the epoxy matrix.