A new approach for science

Barack Obama's victory in the US presidential election is good news for researchers.

Nanopores, nanomotors, negative refraction...

Material witness: Juggling with liquids

Glass and mineral corrosion: Dynamics and durability

The durability of glasses and minerals in water has traditionally been predicted using models that ignore the molecular details. Now the surface structure dynamics are shown to play an integral role in their aqueous corrosion.

Iron-based superconductors: Unity or diversity?

Does the high-temperature superconductivity observed in the newly discovered iron pnictides represent another example of the same essential physics responsible for superconductivity in the cuprates, or does it embody a new mechanism?

Polymer dynamics: Floored by the rings

The tube model can explain how mutually entangled polymer chains move and interact, but it relies on the loose ends of chains to generate relaxation. Ring polymers have no ends — so how do they relax?

Superconductivity: Squash and sandwiches

Externally applied pressure induces superconductivity in the layer compound 1T-TaS2. Similarities to, and differences from, other superconducting systems promise exciting future experiments on this old, but suddenly rejuvenated, compound.

Tissue engineering: Polymers flex their muscles

Accordion-like honeycomb scaffolds support the formation of anisotropically contracting heart tissue in vitro, opening up possibilities in the area of cardiac tissue repair.

Crystal structure prediction from first principles

Insight into silicate-glass corrosion mechanisms

Understanding the corrosion mechanism of aqueous silicate glass is crucial for the long-term durability of nuclear waste glasses. This mechanism is generally thought to be associated with chemical affinity, but it is now demonstrated that morphological transformations also have an important role in the leaching kinetics of these glasses.

Accordion-like honeycombs for tissue engineering of cardiac anisotropy

Construction of tissue-engineering scaffolds that mimic cardiac anisotropy is a challenge. Now, accordion-like honeycomb scaffolds have been created that can form tissue grafts with preferentially aligned heart cells, and with mechanical properties that closely resemble the anisotropy of native myocardium.

Hierarchical nanofabrication of microporous crystals with ordered mesoporosity

Zeolite nanocrystals with three-dimensionally ordered mesoporous structures are important for designing molecularly accessible and selective catalysts. With a single zeolite synthesis procedure, uniform nanocrystals and crystal zeolites with ordered imprinted mesoporosity can now be obtained.

Unexpected power-law stress relaxation of entangled ring polymers

How do entangled polymer rings relax? Linear polymers can ease their stress because their chains have ends, but cyclic polymers do not. Even trace amounts of linear chains dominate the mechanical properties if present as impurities. Investigation of carefully purified ring polymers reveals they exhibit self-similar dynamics and a power-law stress relaxation.

A map for phase-change materials

Phase-change materials are widely used as non-volatile memories, for example in optical data storage, but the search for improved phase-change materials has proved difficult. Based on a fundamental understanding of their bonding characteristics, a systematic prediction of phase-change properties has now become possible.

Electronic two-terminal bistable graphitic memories

Carbon-based structures are being intensively investigated for their use in electronic devices. A pronounced non-volatile switching is now observed in two-terminal devices made from graphitic sheets. The highly reliable switching mechanism is explained by the local breaking and rejoining of atomic bonds in the sheets.

Ultrahigh stress and strain in hierarchically structured hollow nanoparticles

Nanocrystalline materials usually exhibit high strength and their deformation caused by stress is limited. Nanocrystalline CdS with spherical and hierarchical shell geometry is shown not only to withstand extreme stresses, but also to deform considerably before failure.

From Mott state to superconductivity in 1T-TaS2

Superconductivity is a complex and fascinating phenomenon, made more so by its coexistence with other collective electronic states. A study of the layered compound 1T-TaS2 under pressure enables the various states of the material to be investigated and compared with other commonly studied layered superconductors.

Single-molecule nanocatalysis reveals heterogeneous reaction pathways and catalytic dynamics

Nanomaterials are effective catalysts for many chemical reactions, however, their catalytic properties are most often determined by ensembles of nanoparticles, and so far only averaged results have been measured. Now, the heterogeneous reactivity and the surface structure dynamics of individual gold nanoparticles are revealed by monitoring single fluorogenic reactions.

Structural and magnetic phase diagram of CeFeAsO1− xFx and its relation to high-temperature superconductivity

According to a neutron-scattering study of the structural and magnetic properties of the pnictide CeFeAsO1−xFx, the phase diagram of this material shows considerable similarities with the high-Tc cuprate superconductors. These results are an important addition to the effort to find out where superconductivity in these iron–arsenic alloys arises.

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