Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Nanocubes Get in a Twist

Competing forces coax nanocubes into helical structures

Nanocubes are anything but child’s play. Weizmann Institute scientists have used them to create surprisingly yarn-like strands: They showed that given the right conditions, cube-shaped nanoparticles are able to align into winding helical structures. Their results, which reveal how nanomaterials can self-assemble into unexpectedly beautiful and complex structures, were recently published in Science.

SEM image of a well-defined double helix

Dr. Rafal Klajn and postdoctoral fellow Dr. Gurvinder Singh of the Institute’s Organic Chemistry Department used nanocubes of an iron oxide material called magnetite. As the name implies, this material is naturally magnetic: It is found all over the place, including inside bacteria that use it to sense the Earth’s magnetic field.

Magnetism is just one of the forces acting on the nanoparticles. Together with the research group of Prof. Petr Král of the University of Illinois, Chicago, Klajn and Singh developed theoretical models to understand how the various forces could push and pull the tiny bits of magnetite into different formations.

“Different types of forces compel the nanoparticles to align in different ways,” says Klajn. “These can compete with one another; so the idea is to find the balance of competing forces that can induce the self-assembly of the particles into novel materials.” The models suggested that the shape of the nanoparticles is important – only cubes would provide a proper balance of forces required for pulling together into helical formations.

The researchers found that the two main competing forces are magnetism and the van der Waals force. Magnetism causes the magnetic particles to both attract and repel one another, prompting the cubic particles to align at their corners. Van der Waals forces, on the other hand, pull the sides of the cubes closer together, coaxing them to line up in a row. When these forces act together on the tiny cubes, the result is the step-like alignment that produces helical structures.

In their experiments, the scientists exposed relatively high concentrations of magnetite nanocubes placed in a solution to a magnetic field. The long, rope-like helical chains they obtained after the solution was evaporated were surprisingly uniform. They repeated the experiment with nanoparticles of other shapes but, as predicted, only cubes had just the right physical shape to align in a helix. Klajn and Singh also found that they could get chiral strands – all wound in the same direction – with very high particle concentrations in which a number of strands assembled closely together. Apparently the competing forces can “take into consideration” the most efficient way to pack the strands into the space.

Although the nanocube strands look nice enough to knit, Klajn says it is too soon to begin thinking of commercial applications. The immediate value of the work, he says, is that it has proven a fundamental principle of nanoscale self-assembly. “Although magnetite has been well-studied – also its nanoparticle form – for many decades, no one has observed these structures before,” says Klajn. “Only once we understand how the various physical forces act on nanoparticles can we begin to apply the insights to such goals as the fabrication of previously unknown, self-assembled materials.”

Dr. Rafal Klajn’s research is supported by the Abramson Family Center for Young Scientists; the estate of Olga Klein Astrachan; and the European Research Council.

Yivsam Azgad | Eurek Alert!
Further information:

Further reports about: Magnetism Weizmann helical magnetite materials particles structures tiny

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>