Researchers at the University of Glasgow have developed a method to control the separation of two liquids in a mixture using lasers. This approach could benefit crystal production, which plays a key role in many industries.The new study is published in Nature Chemistry.
The scientists used a low-power laser to interact with two liquids at a critical point, the temperature at which it is possible to separate the two liquids. The laser allowed them to control this phase separation with precision. The researchers believe that this approach could be used in nucleation, the initial process in the formation of crystals.
“In our experiments, we used a simple mixture of two liquids and a relatively low power laser diode to suck one of the liquids out of the mixture. So it’s a little bit like making a cup of tea, stirring in some milk, and then using a laser to suck the milk out again,” Professor Klaas Wynne, who designed and developed the approach, said in a statement. “It may seem really counter-intuitive but it’s all within the laws of physics.”
While crystals are well studied and have many applications, their formation is still riddled with uncertainty. A crystal can star in a solid, liquid, or vapor. To begin with, a small number of atoms (or molecules) will begin to interact, and they arrange themselves into a well-defined pattern. As more atoms interact with this site, they continue to get arranged in the same pattern. And so the crystal grows.
Researchers think that liquids undergoing phase separation can start the nucleation process and form crystals. Understanding and maybe even inducing nucleation in liquids would have important consequences in crystals creation.
“These are the first steps towards a full understanding of the role that critical fluctuations play in crystal nucleation. Our aim is to gain full control over nucleation, including the type of crystal that is produced,” Finlay Walton, the graduate student who carried out the work, added.
Crystals are used in computers, phones, and similar technologies. They are used to make drugs, paints, in light bulbs, and solar cells. Being able to regulate crystal growth could cut industrial waste, and, of course, make them cheaper.