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In the present study, poly­(ethylene glycol) (PEG) functionalized carbon nanotubes (CNT-PEG) were used as nanoadditives to fabricate hybrid membranes for enhanced CO2 separation in Pebax 1657 matrix. The resultant membranes were characterized using various techniques. It is found that grafting PEG onto CNT fibers greatly improves the CNT dispersion. No noticeable aggregation can be found in the hybrid membranes with CNT-PEG content of up to 20 wt %. X-ray diffraction results denote that the CNT-PEG in the Pebax matrix increases the amorphous phase content, which is beneficial for CO2 permeation. Gas permeation properties were investigated using mixed gas permeation tests at different relative humidity conditions. It is found that CO2 permeability first increases and then decreases with increasing CNT-PEG content at the dry state. The water vapor in the gas stream further improves the CO2 permeability. At 100% relative humidity, CO2 permeability of 369.1 barrer with CO2/N2 selectivity of 110.8 was obtained for a hybrid membrane containing 3 wt % CNT-PEG, which overcomes the Robeson upper bound. The combination of high permeability and selectivity makes the Pebax/CNT-PEG hybrid membranes promising for industrial CO2 separation applications.

This work reports the first demonstration of the chemical reactions on the C–F groups of perfluorosulfonic acid polymers. The Nafion chains show chemical reactivity for atom transfer radical addition onto multiwalled carbon nanotubes and ability to serve as a macroinitiator for atom transfer radical polymerization. The C–F groups and mainchain −CF2 groups have been demonstrated, under a study with 19F NMR, as the active sites responsible for the reactions. The results could certainly extend both the scopes of chemistry and application of perfluorosulfonic acid polymers as well as the windows of atom transfer radical addition/polymerization to fluorinated compounds.

Multiblock polystyrene/C 60 nanohybrid block copolymers have been prepared with sequential atom transfer radical polymerization using 1-bromoethylbenzene and dimethyl-2,6-dibromoheptanediaote as monofunctional and difunctional initiators, respectively. The polystyrene/C 60 nanohybrids have been characterized with gel permeation chromatography and UVÀvis spectrometry. The self-assembly behaviors of the polystyrene/C 60 nanohybrids have been studied. The multiblock polystyrene/C 60 nanohybrids tend to form toroids in chloroform and to form spherical aggregates in the mixture of chloroform and methanol. Moreover, selective polystyrene/C 60 nanohybrids also form toroids in cyclohexane. The toroids shapes and formation mechanism in cyclohexane are different from those in chloroform. The polystyrene/C 60 nanohybrids are a new group of materials for toroids preparation and application. ' INTRODUCTIONCreation and control of the curvature and topology is important and interesting for the preparation of novel and functional soft materials. In contrast to the low-molecular-weight surfactants, macromolecular amphiphiles received much research attention of morphological assemblies. 1 The chain structures of the amphiphilic polymers play an important role in their self-assembly behaviors. 2 As a result, triblock copolymers, compared to diblock copolymers, are expected to demonstrate assembled aggregates having novel morphologies and properties. Some theoretical and simulated studies revealed the formation of ring-shaped aggregates in wormlike micellar systems 3À5 and opened the window to the scope of toroidal structures from amphiphilic block copolymers. Nevertheless, the theoretical prediction told that the presence of toroidal structures might be very difficult as their regime of formation was very narrow. 5 Jiang's group found that increases in the annealing time help the transformation of the amphiphilic polystyrene (PS)/poly(4-vinylpyridine) (PVP) ABA triblock copolymer from a rodshaped structure to a ring-shaped structure in a dioxane/water mixture solution. 6 The effect of shear flow rate on the formation of ring-shaped micelles of the same triblock copolymer was also examined. 7 Formation of the ring-shaped micelles at different flow rates performed via different pathways. Wang and Jiang further demonstrated the temperature-induced reversible transformation between toroidal and cylindrical micelles of the polystyrene poly(4-vinylpyridine) triblock copolymer. 8 Pochan and co-workers 9 reported the toroidal micelles of poly(acrylic acid-b-methyl acrylate-b-styrene) by mimicking the self-assembly behavior of DNA induced by multivalent counterions. Dilute polymer solutions and slow evaporation of tetrahydrofuran in the aqueous solutions are essential for eventual toroid formation. The research group also studied the effect of block copolymer compositions and sequence on the formation of toroidal morphology of triblock copolymers. 10 Formation of toroids could be only observed with specific copolymers. A successive paper re...