Magnetic nanocubes self-assemble into spirals


nanocube

© AAAS/Science

Scientists have been coaxing nano-sized cubes of magnetite (Fe3O4) into larger, more complex structures like helices without using a template by exposing them to a magnetic field.

A team led by Rafal Klajn at the Weizmann Institute of Science in Israel found that by varying the density of the cubes and the size and direction of the magnetic field they can control the kind of structure the cubes self-assemble into, which depends on the interplay between intermolecular forces and magnetic interactions. Under an increasing magnetic field the nanocubes line up to make a ‘belt’, while under a constant magnetic field at high density they curl round and form a helix. Single helices tend to clump together to make double helices (like the rope-like structure shown above) or even triple helices.

Although at the moment there is no obvious use for the structures, the team say they could have interesting magnetic properties. They are now exploring the effects of using other magnetic nanomaterials, such as nickel or iron nanoparticles, and decorating the nanocube surfaces with functional ligands to see what other shapes can be made.


Related Content

The golden helix

10 October 2012 Premium contentFeature

news image

Fifty years after the Nobel prize was awarded for the structure of DNA, Mike Sutton looks back at how it all came about

Keratin

26 September 2012 Podcast | Compounds

news image

This week's podcast is about keratin

Most Read

Graphene sandwich turns water square

27 March 2015 Research

news image

Water trapped between graphene sheets transformed into new type of ice

Simple cooking changes make healthier rice

23 March 2015 Research

news image

Adding oil to water, cooling and reheating rice makes fibre-like resistant starch, reducing calories

Most Commented

Sewage offers attractive source of precious metals

27 March 2015 Research

news image

US Geological Survey team finds valuable metals in treated sewage and is working on the difficult problem of extraction

Thinking ahead

26 March 2015 Critical Point

news image

PhD courses must prepare students for a life after research, says Mark Peplow