For the first time ever, researchers have succeeded in creating arrangements of colloids – tiny particles suspended in a solution – and, importantly, they have managed to control their motion with high precision and speed. Thanks to this new technique developed by scientists at the University of Zurich, colloidal nanoparticles may play a role in digital technologies of the future. Nanoparticles can be rapidly displaced, require little energy and their small footprint offers large storage capacity – all these attributes make them well suited to new data storage applications or high-resolution displays.
Colloids are minute particles that are finely distributed throughout a liquid. Suspensions of colloidal particles are most familiar to us as beverages, cosmetics and paints. At a diameter in the range of ten to one hundred nanometres, a single such particle is invisible to the naked eye. These nanoparticles are constantly in motion due to the principle of Brownian motion.
A nanorod is switched between two states – bright (high signal) and dark (low signal) by an external electrical pulse (red trace). The state of the rod can be readout instantaneously at any time using polarized light. The rod stores the most recently written state until the arrival of the next «write pulse». (Image: UZH)
Since the particles are electrically charged, they experience forces of attraction and repulsion that can be harnessed to control and manipulate their behavior. In experiments carried out five years ago, Madhavi Krishnan, Professor of Physical Chemistry at the University of Zurich, succeeded in the controlled spatial manipulation of matter on the nanometer scale.
In a new study, she and her colleagues have now demonstrated that it is not only possible to spatially confine nanoparticles, but also to control their position and orientation in time and to do so in a liquid, without using physical contact.
Manipulation using electrical and optical signals
The UZH researchers have developed a method that makes it possible to create nanostructures and manipulate them in a flexible way. They were able to organise the tiny particles into new structures with the utmost precision and then to manipulate their motion. «Manipulation is made possible by the interaction with electrical and optical fields», explains Madhavi Krishnan. This new approach using intermolecular interactions at room termperature does not require ultracold temperatures. The new technology also offers extremely fast and low-friction operation.
Smaller, faster and with more storage capacity
This technique for arranging and manipulating colloid motion makes it possible to develop completely new materials and devices. «Nanoparticles possess properties that are very useful for digital technologies, and each individual particle can now be used to store and retrieve data», explains Madhavi Krishnan. The targeted manipulation of individual nanoparticles opens up new options for their application, including in future data storage media or in displays with resolutions that have thus far been hard to attain. «This makes possible displays along the lines of the Kindle reader with a pixel size that is thousand-times smaller and a much faster response time» the scientist explains.
Christopher J. Myers, Michele Celebrano and Madhavi Krishnan. Information storage and retrieval in a single levitating colloidal particle. Nature Nanotechnology, August 17, 2015.
Evelyne Brönnimann | Universität Zürich
Two dimensional circuit with magnetic quasi-particles
22.01.2018 | Technische Universität Kaiserslautern
Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
22.01.2018 | Materials Sciences
22.01.2018 | Earth Sciences
22.01.2018 | Life Sciences