For the first time ever scientists at the University of Zurich have managed to arrange colloids and to successfully control their motion with high precision and speed. It is a quite significant achievement, allowing for digital technologies of the future to rely on these colloidal nanoparticles. This technology in the future may be used to create new data storage applications or high-resolution displays.
This is allowed by some important qualities that scientists managed to achieve. These nanoparticles can be rapidly displaced, require little energy and have a small footprint. These nanoparticles are colloids – small particles that are finely distributed throughout a liquid.
Although they may seem like something that is only relevant in laboratories, we actually know and use some suspensions of colloidal particles – some beverages, cosmetics and paints are actually colloidal particles. Because of its minute size, colloid is invisible to a naked eye – it has a diameter in the range of ten to one hundred nanometres – and they are constantly in motion due to the principle of Brownian motion.
These particles are electrically charged and, therefore, experience forces of attraction and repulsion. This property can be used to control and manipulate their behaviour. Colloids have always interested scientists – five years ago scientists succeeded in the controlled spatial manipulation of matter on the nanometre scale. However, now they achieved even more. They proved that it is not only possible to spatially confine nanoparticles, but also to alter their position and orientation in time. Moreover, it is possible to do so in liquid, without physical contact with those particles.
In order to achieve this high-precision control of nanoparticles, scientists at the University of Zurich have developed a new technique, which allows for creating nanostructures and manipulating them in a very flexible way. In fact, this method is so advanced it allowed scientists to arrange these minute particles into new structures with the incredible precision and then to manipulate their motion even further. Professor Madhavi Krishnan, leader of the research team, explained that “manipulation is made possible by the interaction with electrical and optical fields”.
The new technique intermolecular interactions at room temperature – it does not require extremely cold temperatures. Technology also offers extremely fast and low-friction operation. Professor Krishnan noted that “nanoparticles possess properties that are very useful for digital technologies, and each individual particle can now be used to store and retrieve data”, which means completely new materials and devices can be developed.
Scientists are using a nanorod. It can be switched between high and low signals by an external electrical pulse. The state of the rod can be readout instantaneously at any time using polarized light and it stores the most recently written state until the arrival of the next electrical pulse. Although it seems to be a fairly complex technique, scientists will be developing it further and we may expect some improvements in the future.
This new technique for manipulation of colloid motion opens up new options for their application. They can be used to create novel data storage solution or displays with resolutions that have thus far been hard to attain. Displays made using colloid particles are very interesting idea, because they could work like digital readers with e-link technologies, but would have much smaller pixels – thousands of times smaller, in fact. This would allow for much higher resolutions and a much faster response time. Therefore, although this may be the first time you are reading about colloids, in the near future you may be reading other articles on the screen that is made using this technology that scientists are currently developing.