Advanced Functional Materials

Molecular assembly of glycosylated polycationic copolymers can provide a well-defined surface platform for the presentation of engineered mono-and oligoglycosides at controlled densities and in specific patterns, as reported by Geraldine Coullerez and co-workers on p. 1459. These engineered surfaces are ideal for the study of adhesion of pathogens to surfaces and are believed to be promising tools to investigate early stages of surface colonization and infection. Escherichia coli adhesion (see cover) is highly specific to the type of mannosides and their density and linker chemistry, and depends strongly on flow rate.

The crystalline phase and morphology of pentacene thin films deposited on a dielectric layer (see figure) can be controlled by changing the molecular ordering structure of organosilane SAMs adsorbed on the dielectric surface. Depending on the physical structure of the dielectric surface, the pentacene nanolayers can adopt two competing crystalline phases – “thin-film” and “bulk” – that affect the π-conjugated nanostructures, causing the field-effect mobility to vary.

A new nanoporous membrane suitable for virus filtration with good dimensional stability under high pressures is introduced. Block copolymer films with mixed orientations of cylindrical nanopores coupled with a conventional supporting membrane showed mechanical stability at high filtering pressure without sacrificing selectivity for the HRV 14 virus. The nanoporous film (see figure) showed excellent resistance to all organic solvents.

Multilayer films made of poly(L-lysine)/hyaluronan (PLL/HA) of controlled stiffness have been used to investigate the effects of the mechanical properties of thin films on skeletal muscle cell (C2C12 cells) differentiation. The film stiffness strongly modulates not only initial myoblast adhesion and proliferation, but also myoblast differentiation into myotubes. On soft films, myotubes are initially short and thick before clumping and detaching. On stiff films, cells form elongated and thin striated myotubes.

A series of poly(N-isopropylacrylamide)-coated mesoporous silica nanoparticles (PNiPAm-MSNs) have been synthesized (see scheme). By controlling the degree of polymerization, these organic–inorganic hybrid nanoparticles exhibit a temperature-dependent solution partition behavior between hydrophobic and hydrophilic solvents.

A new class of dual luminescent sensors for determination of pressure and temperature is presented, capable of imaging both analytes simultaneously in surpassing spatial resolution (see figure). The signals of the two probes, a Pt-porphyrin for pressure and a Eu-complex for temperature, are separated by means of their different luminescence lifetimes.

Stabilizing “active” centers (bismuth) in a “tolerant” host (nanoporous silica glass) is shown to be a facile approach to creating a tunable ultra-broadband light source. The obtained materials, in which unusual multiple bismuth centers (Bi⁺, Bi²⁺, and Bi³⁺) are stabilized, emit in an ultra-broadband range from blue-green, orange, red, and white to the near-infrared region (see figure), which covers the spectral range of the traditional three primary colors for white light and also the telecommunications window.

Negatively charged, three-dimensional (Au/PAH)₄(PSS/PAH)₄ multilayer-coated PS spheres are prepared to modify a boron-doped diamond electrode (BDD) for the determination of dopamine (DA) and ascorbic acid (AA). The modified BDD electrodes shows high electrocatalytic activity toward the oxidation of DA and inhibits the electrochemical reaction of AA, and can effectively determine DA in the presence of AA with good selectivity.

Composition-and size-dependent bandgap functions (E_g(x,D)) are modeled for homogeneously alloyed pseudo-binary IIB–VIB chalcogenide semiconductor nanoparticles. The modeling corresponds well with available experimental results (see figure; symbols are experimental results). It is found that the bowing shape of the function with changes in composition becomes weak as the nanoparticle size decreases, while the atomic interaction between the alloy compositions is negligible.

Highly efficient red-electrophosphorescent devices have been realised by incorporating Os complexes into the conjugated backbone of a blue polyfluorene copolymer that contains both hole-and electron-transporting pendent groups. The best device performance is a maximum external quantum efficiency of 18.0% with a peak brightness of 38 000 cd m⁻².

A typical core–ring nanostructure occurs in NiCo₂O₄ nanoplatelets. It is revealed by energy dispersive spectroscopy analysis that the cation concentration of Co (Ni) in this structure gradually increases (decreases) from the ring to the core. These core–ring nanoplatelets are active anode catalysts for water electrolysis.

A film of ZnO/ZnAl₂O₄ nanosheets, which was derived from ZnAl-(CO₃)²⁻ layered double hydroxides by calcination, has been used directly as the anode material for Li-ion batteries (0.05–2.5 V at 200 mA g⁻¹). The nanostructured film exhibits higher discharge and charge capacities and considerably improved cycling stability as compared to a pure ZnO nanoparticle film.

Molecular assembly of glycosylated polycationic copolymers is demonstrated as a quantitative surface platform for the presentation of engineered mono- and oligoglycosides at controlled surface densities, suitable for the production of homogeneous and micropatterned carbohydrate surfaces. E. coli adhesion (see figure) is highly specific to the type of mannosides and their density, linker chemistry, and depends strongly on flow rate.