A team of researchers from Brave Analytics GmbH, in collaboration with a colleague from the Gottfried Schatz Research Center and another from the Institute of Physics, all in Austria, developed a device capable of conducting the characterization of nanoparticles in real time. The group has published their work in the magazine Applied physical review.
Over the past few decades, product engineers have been adding more and more nanoparticles to products to give them the desired qualities, such as for thickening or coloring paints. The types of nanoparticles used depend on many factors, such as their composition and shape, which are generally easily determined. The size of the nanoparticles is also important to ensure consistency, but figuring out how big they are has proved more difficult. An approach called dynamic light scattering has been found to work well, but only with tiny nanoparticles. In this new effort, the researchers have created a device that can be used to determine the size of larger nanoparticles.
The new device is based on the induction of optofluidic force (OF2i). It consists of a transparent cylinder and a laser beam. During use, the cylinder is filled with water in which sample nanoparticles have been added, in this case tiny fragments of polystyrene. The laser is fired in a way that allows the light to travel in a spiral through the water, forming a vortex of water.
Laser light is used in two ways: to push nanoparticles through water and to follow their movement. In such a configuration, the amount of acceleration a given nanoparticle undergoes will depend on its size. Researchers suggest it is similar to a sailboat. Two boats of the same size experiencing the same wind force will be propelled at different speeds if they have different sized sails. And because the laser forms a vortex, the nanoparticles travel in a spiral, making collisions less likely.
The scattered light after bouncing off the nanoparticle can then be observed with a time-lapse microscope, which can reveal the paths followed by the individual nanoparticles. The analysis of the shape of these trajectories can be used to determine the speed variations due to the force exerted by the laser and thus reveal the size of the nanoparticles. Tests showed that the device is capable of measuring nanoparticles in the range of 200 to 900 nm.
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Marko Šimić et al, Characterization of nanoparticles in real time through the induction of optofluidic force, Applied physical review (2022). DOI: 10.1103 / PhysRevApplied.18.024056
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Citation: Optofluidic Force Induction Enables Real-Time Characterization of Nanoparticles (2022, September 9) Retrieved September 10, 2022 from https://phys.org/news/2022-09-optofluidic-induction-real-time-nanoparticle -characterization.html
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