Articles in 2010

Plasmon lasers can operate at dimensions well below the diffraction limit. Their small size promises uses in nanophotonic circuits and for other size-critical applications. The demonstration of a sub-diffraction-limited plasmon laser with low losses, which enables its room-temperature operation, takes a significant step towards realizing the potential of these lasers.

This two-dimensional crystal keeps playing a dominant role in physics and materials science.

The practical use of electronic ratchets has long been hampered by low output powers and cryogenic operating temperatures. A pentacene-based organic ratchet can now drive electronic circuitry at room temperature.

Empty liquids and equilibrium gels have so far been only theoretical possibilities, predicted for colloids with patchy interactions. But evidence of both has now been found in Laponite, a widely studied clay.

A suitably chosen thin layer inserted between a ferromagnetic electrode and an organic semiconductor allows control over the polarization of the injected spins.

The first diffraction patterns from the individual atomic packing clusters in a metallic glass finally enable the direct study of local order in amorphous alloys.

The friction and wear of materials is part of our everyday experience, and yet these processes are not well understood. The example of diamond highlights wear processes that result from bumping atoms, showing that the devil is indeed in the details.

Atomic force microscopy experiments on individual blood platelets reveal their dynamic contractile response to varied stiffness of the substrate.

High annealing temperatures have limited the technological potential of solution-processed metal oxide semiconductors. It is now shown that high-quality films can be formed below 250 °C using precursors that are hydrolysed on-chip.

In chemistry, some dynamic bonds can be selectively and reversibly broken and reformed in response to an environmental stimulus. This Review article discusses the incorporation of dynamic bonds, or interactions, in polymeric materials and the structural changes and macroscopic responses observed in the presence of different stimuli.

Theoretical models of colloids with directional and anisotropic interactions have predicted the existence of both liquids with vanishing density, and arrested networks at equilibrium — that is, not undergoing phase separation. Experimental evidence of empty liquids and equilibrium gels is now provided for Laponite, a synthetic clay. These observations further our understanding of anisotropic interactions in colloidal suspensions.

A one-step preparation method of electrospun, synthetic scaffolds with controlled surface chemistry and functionality is reported. On addition of amphiphilic macromolecules, non-specific protein adsorption on the fibres’ surfaces is reduced, and by the further covalent attachment of certain peptide sequences to the fibres, specific bioactivation of the scaffold is achieved.

A low-temperature, solution-based preparation of amorphous, metal oxide semiconducting thin-films is reported. This ‘sol–gel on chip’ hydrolysis approach yields thin-film transistors with high field-effect mobilities, reproducible and stable turn-on voltages and high operational stability.

Ratchet systems can extract work from non-equilibrium processes. Yet present electronic ratchets only operate at cryogenic temperatures and generate low currents, which are clear limitations for their practical use. Now, organic electronic ratchets providing enough power to drive simple logic circuits at room temperature have been realized.

A polymeric hydrogel coating shows impressive antimicrobial activity against both bacteria and fungi. The biocompatible and reusable coating, formed of a polycationic nanoporous hydrogel, is thought to act by drawing anionic sections of phospholipids on bacterial cell membranes into its pores, causing membrane disruption and cell death.

Sodium layered oxides are low-dimensional and strongly correlated systems that have been extensively studied because of their intriguing structural and physical properties. Electrochemical sodium intercalation is now used to investigate their different phase domains and thermal stability.