Volume 7 Issue 8, August 2008

As economic competition in the region increases, Hong Kong has to reinvent itself as a knowledge-based society.

The fast-paced economic development in China needs to be complemented by strong support for fundamental research, particularly in the materials sciences.

Nature Materials spoke to Lu Yongxiang, President of the Chinese Academy of Sciences, on the roles that the academy and its more than 100 research-related institutions have in advancing science and technology in China.

The in vivo characteristics of the extracellular matrix, such as biochemical, mechanical and flow properties, are a challenge to mimic in vitro. Now, a three-dimensional hydrogel structure with integrated multiple phases shows promise as such a model.

The propagation of submillimetre cracks reveals how the numerous internal structural dimensions in bone lead to a toughness that varies with orientation and scale.

Colloidal nanocrystals randomly turn their photoluminescence off and on under continuous light illumination. Growing thick shells around the crystals can reduce the blinking effect dramatically, with great potential advantage for applications.

Fluorine-containing species can cause titania to crystallize with an unusually large fraction of reactive {001} facets.

Controlling simultaneously the electric and thermal properties of materials can lead to very efficient thermoelectric devices. Advances following different routes were highlighted at a recent conference.

Biological factors are not the only influence on stem-cell behaviour — the physics and chemistry of the environment play a part too. The interaction of materials science and stem-cell science brings with it a wealth of opportunities for future therapies.

The interfaces between some perovskite oxide insulators show spectacular electronic properties, originating from the formation of an electron gas. The spatial extent of the electron gas is still under debate. Conducting tip atomic force microscopy is now used to show that, depending on the growth conditions, the high-mobility electron gas can extend to hundreds of micrometres or to just a few nanometres from the interface.

The presence of organic solvents in solar cells has hindered the application of devices, especially in flexible cells. Now, by mixing three solid salts, a solvent-free liquid electrolyte for dye-sensitized solar cells has been discovered that shows both excellent efficiency and stability.

Elucidation of the framework structure of zeolites can sometimes prove difficult. The combination of powder diffraction and electron microscopy using a charge-flipping algorithm enables ordered silicon vacancies in a zeolite catalyst to be revealed.

The contractile forces of cells can cause extracellular matrices to detach from their surroundings, which is problematic for biological studies and tissue engineering. Now, multiple phases of cell-seeded hydrogels can be integrated using a collagen-fibre-mediated method, resulting in the construction of well-defined and stable patterns of three-dimensional matrices.

Typically, metal alloys are protected from corrosion through the formation of an oxide layer. Nevertheless, alloy degradation does occur. It is now shown that metallic nanoparticles in the oxide layer are instrumental to this process. On the basis of this understanding, improvements in alloy degradation by careful choice of composition are demonstrated.

Recent work has provided evidence for the existence of a liquid–liquid transition (LLT) in some single-component fluids. It is now shown that the LLT can be used to control the fluidity and miscibility of triphenyl phosphite with another molecular liquid, demonstrating the possibility of the first definite application for exploiting this phenomenon.

Although phase-change materials are of significant importance for optical and electronic information storage applications, the search for new materials so far has been based on empirical methods. Now, the discovery that their crystalline phase shows resonant bonding opens the way to a deterministic search for new phase-change materials.

One of the obstacles in using nanocrystals as fluorophores is that they tend to blink. This was thought to be a very general feature. Now, very-high-quality core–shell CdSe–CdS nanocrystals showing highly reduced blinking have been grown. The reduced blinking seems to be related to the thickness of the CdS shell and the high quality of the core–shell interfaces.

Although lithium iron phosphate is a promising electrode material for lithium-ion batteries, its intercalation mechanism remains unclear. Characterization by X-ray diffraction and electron microscopy demonstrates that the lithium deintercalation process occurs as a wave moving through the crystal, and can be described by a domino-cascade model

The toughness of human bone is difficult to measure, as it is more difficult to break than to split. It is now shown that in the transverse orientation, relevant for breaking, bone is much tougher than previously thought owing to a surprising increase in toughness during the growth of small cracks.

Since the opening of the country to the outside world thirty years ago, the output of scientific publications in materials science from China has risen from almost nowhere into now being the third largest in the world. In this special issue of Nature Materials we take a look at this rapid development in China.