By combining three mutually immiscible polymeric components in a mixed-arm star block terpolymer architecture, we have observed the formation of a previously unknown class of multicompartment micelles in dilute aqueous solution. Connection of water-soluble poly(ethylene oxide) and two hydrophobic but immiscible components (a polymeric hydrocarbon and a perfluorinated polyether) at a common junction leads to molecular frustration when dispersed in aqueous solution. The incompatible hydrophobic blocks form cores that are protected from the water by the poly(ethylene oxide) blocks, but both are forced to make contact with the poly(ethylene oxide) by virtue of the chain architecture. The structures that emerge depend on the relative lengths of the blocks and can be tuned from discrete multicompartment micelles to extended wormlike structures with segmented cores.

Translating the unique characteristics of individual single-walled carbon nanotubes into macroscopic materials such as fibres and sheets has been hindered by ineffective assembly. Fluid-phase assembly is particularly attractive, but the ability to dissolve nanotubes in solvents has eluded researchers for over a decade. Here, we show that single-walled nanotubes form true thermodynamic solutions in superacids, and report the full phase diagram, allowing the rational design of fluid-phase assembly processes. Single-walled nanotubes dissolve spontaneously in chlorosulphonic acid at weight concentrations of up to 0.5 wt%, 1,000 times higher than previously reported in other acids. At higher concentrations, they form liquid-crystal phases that can be readily processed into fibres and sheets of controlled morphology. These results lay the foundation for bottom-up assembly of nanotubes and nanorods into functional materials.

Graphene combines unique electronic properties and surprising quantum effects with outstanding thermal and mechanical properties. Many potential applications, including electronics and nanocomposites, require that graphene be dispersed and processed in a fluid phase. Here, we show that graphite spontaneously exfoliates into single-layer graphene in chlorosulphonic acid, and dissolves at isotropic concentrations as high as approximately 2 mg ml(-1), which is an order of magnitude higher than previously reported values. This occurs without the need for covalent functionalization, surfactant stabilization, or sonication, which can compromise the properties of graphene or reduce flake size. We also report spontaneous formation of liquid-crystalline phases at high concentrations ( approximately 20-30 mg ml(-1)). Transparent, conducting films are produced from these dispersions at 1,000 Omega square(-1) and approximately 80% transparency. High-concentration solutions, both isotropic and liquid crystalline, could be particularly useful for making flexible electronics as well as multifunctional fibres.

An asymmetric poly(styrene-b-isoprene) diblock copolymer with block molecular weights of 13 000 and 71 000 g/mol, respectively, was dissolved at 1 vol % in a series of solvents with varying selectivity for styrene: dibuthyl phthalate (DBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP). The degree of solvent selectivity was adjusted by mixing DBP/DEP and DEP/DMP in various proportions. With increasing solvent selectivity, the predominant micellar shape changes from spheres to cylinders to vesicles, reflecting the changing interfacial curvature. The detailed micellar morphologies were characterized by small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM). Recently developed form factors were used to characterize the micellar structures in detail, and a vesicle form factor was derived for this system. From the core dimensions, the packing properties, such as the interfacial area per chain and the core chain stretching, were determined. The cryo-TEM results demonstrate the suitability of the technique for these glass-forming solvents and gave micellar core dimensions in quantitative agreement with those from SAXS. The universality of the shape sequence sphere/cylinder/vesicle, well-established for aqueous solutions of surfactants and block copolymers, is thus confirmed for organic systems.