Laser tweezers used to boost liquid crystal technology

CHICAGO. KAZINFORM U.S. researchers said that by using a combination of flow and light, they can create defects that remain stable in the liquid crystal over long periods of time.

The breakthrough could ultimately result in using liquids in new ways, such as to create new kinds of autonomous materials or nanoscale reactors, said a news release posted on the website of the University of Chicago Friday, Xinhua reports.

To create the defects in the liquid crystals, researchers with the Institute for Molecular Engineering at the University of Chicago and the University of Ljubljana used laser tweezers, a laser system that can manipulate particles at the nanoscale, to heat up and melt either a tiny point or a line within the material.

While the bulk of the liquid crystal remained ordered, the melted spot, several microns in size and just a little smaller than a single red blood cell, became disorganized. As it cooled, the molten liquid becomes reordered, and forms a defect on its trail,

As such defects cost the material energy, the material experiences strong driving forces to eliminate them, and it eventually reverts to a uniform, defect-free state.

To resolve the problem, the researchers place the defect into a flow state in a microfluidic device, introducing forces that continually push the defect in different directions so that it could not reorient and annihilate itself, and instead remained stable.

The system also allowed the researchers to have complete control over the size and shape of the defects.

The system could pave the way for new display or sensor technologies. The researchers are trying using this technique to develop complicated networks of microfluidic channels that could serve as miniature factories, with built-in reactors, separation units and transport mechanisms.

They also are looking to develop autonomous material systems that can stabilize defects on their own using flows.

The breakthrough has been published in the journal Science Advances.

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