Non-spherical nanostructures derived from soft matter and with uniform size-that is, monodisperse materials-are of particular utility and interest, but are very rare outside the biological domain. We report the controlled formation of highly monodisperse cylindrical block copolymer micelles (length dispersity < or = 1.03; length range, approximately 200 nm to 2 microm) by the use of very small (approximately 20 nm) uniform crystallite seeds that serve as initiators for the crystallization-driven living self-assembly of added block-copolymer unimers with a crystallizable, core-forming metalloblock. This process is analogous to the use of small initiator molecules in classical living polymerization reactions. The length of the nanocylinders could be precisely controlled by variation of the unimer-to-crystallite seed ratio. Samples of the highly monodisperse nanocylinders of different lengths that are accessible using this approach have been shown to exhibit distinct liquid-crystalline alignment behaviour.

Although solution self-assembly of block copolymers (BCPs) represents one of the most promising approaches to the creation of nanoparticles from soft matter, the formation of non-centrosymmetric nanostructures with shape anisotropy remains a major challenge. Through a combination of crystallization-driven self-assembly of crystalline-coil BCPs in solution and selective micelle corona cross-linking, we have created short (about 130 nanometers), monodisperse cylindrical seed micelles that grow unidirectionally. These nanostructures grow to form long, non-centrosymmetric cylindrical A-B and A-B-C block co-micelles upon the addition of further BCPs. We also illustrate the formation of amphiphilic cylindrical A-B-C block co-micelles, which spontaneously self-assemble into hierarchical star-shaped supermicelle architectures with a diameter of about 3 micrometers. The method described enables the rational creation of non-centrosymmetric, high aspect ratio, colloidally stable core-shell nanoparticles in a manner that until now has been restricted to the biological domain.

Herein we report a general liquid-mediated pathway for the growth of continuous polymeric carbon nitride (C3N4) thin films. The deposition method consists of the use of supramolecular complexes that transform to the liquid state before direct thermal condensation into C3N4 solid films. The resulting films exhibit continuous porous C3N4 networks on various substrates. Moreover, the optical absorption can be easily tuned to cover the solar spectrum by the insertion of an additional molecule into the starting complex. The strength of the deposition method is demonstrated by the use of the C3N4 layer as the electron acceptor in a polymer solar cell that exhibits a remarkable open-circuit voltage exceeding 1 V. The easy, safe, and direct synthesis of carbon nitride in a continuous layered architecture on different functional substrates opens new possibilities for the fabrication of many energy-related devices.

Specific molecular recognition is routine for biology, but has proved difficult to achieve in synthetic systems. Carbohydrate substrates are especially challenging, because of their diversity and similarity to water, the biological solvent. Here we report a synthetic receptor for glucose, which is biomimetic in both design and capabilities. The core structure is simple and symmetrical, yet provides a cavity which almost perfectly complements the all-equatorial β-pyranoside substrate. The affinity for glucose, at Ka ~18,000 M-1 , compares well with natural receptor systems. Selectivities also reach biological levels. Most other saccharides are bound ~100 times more weakly, while non-carbohydrate substrates are ignored. Glucose-binding molecules are required for initiatives in diabetes treatment, such as continuous glucose monitoring and glucose-responsive insulin. The performance and tunablity of this system augur well for such applications.

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We present an efficient synthesis of a modified carbon nitride photocatalyst by using supramolecular complexes of cyanuric acid, melamine, and 2,4-diamino-6-phenyl-1,3,5-triazine as precursors. We combined a self-templating approach for morphology control with the modification of photophysical properties by altering the chemical structure of the material. The resulting carbon nitrides exhibit high surface areas, defined morphologies, and a strong enhancement of light absorption in the visible-light region. A detailed analysis shows that the ratio changes of the three raw monomers resulted in different carbon nitride morphologies, absorption, and emission properties, along with the incorporation of different numbers of phenyl groups in the resulting carbon nitride structures. The modified carbon nitrides exhibit superior activity in the photodegradation of rhodamine B, up to 16 times that of bulk carbon nitride. The pyrolysis of rationally chosen supramolecular hydrogen-bonded precursors constitutes a synthetic pathway for the simple one-pot preparation of efficient, metal-free carbon nitride photocatalysts.

The self-assembly of block copolymers in selective solvents represents a powerful approach to functional core-shell nanoparticles. Crystallization of the core can play a critical role in directing self-assembly toward desirable, nonspherical morphologies with low mean interfacial curvature. Moreover, epitaxial growth processes have been implicated in recent advances that permit access to monodisperse cylinders, cylindrical block comicelles with segmented cores and/or coronas, and complex hierarchical architectures. However, how the core-forming block crystallizes in an inherently curved nanoscopic environment has not been resolved. Herein we report the results of synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) studies of well-defined, monodisperse crystalline-coil polyisoprene-block-polyferrocenylsilane cylindrical micelles aligned in an electric field. WAXS studies of the aligned cylinders have provided key structural information on the nature of the PFS micelle core together with insight into the role of polymer crystallinity in the self-assembly of these and potentially related crystalline-coil block copolymers.

Irradiation of silicon-bridged [1]ferrocenophane [Fe(eta-C(5)H(4))(2)SiMe(2)] (1) in the presence of substitutionally labile Lewis bases such as 4,4'-dimethyl-2,2'-bipyridine (Me(2)bpy) initiates ring-opening polymerization and oligomerization via cleavage of an iron-cyclopentadienyl bond. A distribution of cyclic polyferrocenylsilane c-PFS (PFS = [Fe(eta-C(5)H(4))(2)SiMe(2)](n)) and a series of cyclic oligomers (2(2)-2(7)) were isolated by column chromatography and fully characterized. Varying temperature and concentration were found to influence the molecular weight distribution and the ratio of polymer to oligomer products, enabling the formation of c-PFS with molecular weights >100 kDa. Cyclic polymer samples were found to possess lower hydrodynamic radii and viscosity and higher glass transition temperatures than those of their linear PFS counterparts (l-PFS) of comparable molecular weight. Compared with crystalline samples of l-PFS of similar molecular weights, c-PFS formed smaller spherulites, as observed by polarizing optical microscopy. While the wide-angle X-ray scattering (WAXS) patterns from lower molecular weight l-PFS were found to differ from those from higher molecular weight samples, those obtained for lower and higher molecular weight samples of c-PFS are identical and resemble diffraction patterns of high molecular weight l-PFS. The electrochemical behavior of each cyclic oligomer 2(2)-2(7) was studied by cyclic and differential pulse voltammetry and was found to depend on whether the oligomer contains an odd or even number of ferrocene units. In contrast to linear analogs, two reversible redox processes of varying intensities were observed for cyclic oligomers containing an even number of iron centers, while three reversible redox processes of varying intensities were observed for cyclic oligomers containing an odd number of iron centers. As the oligomer chain length increased, the electrochemical behavior of all cyclic oligomers approached that of both cyclic and linear high molecular weight polymers.