Researchers Develop Smart Coating via Color

WEDNESDAY, AUGUST 19, 2020


Scientists at the Pritzker School of Molecular Engineering at the University of Chicago have announced that they have developed a way to stretch and strain liquid crystals to generate different colors.

By creating a thin film of polymer filled with liquid crystal droplets and then manipulating it, they have determined the fundamentals for a color-changing sensing system that could be used for smart coatings, sensors and even wearable electronics, according to the university.

The research, which was led by Juan de Pablo, professor of molecular engineering, was recently published in the journal Science Advances.

The Findings

The team primarily looked at chiral liquid crystals, which have twists and turns and a certain asymmetrical “handedness”—like right-handedness or left-handedness, according to officials—that allows them to have more interesting optical behaviors.

These crystals can also form “blue phase crystals,” which have properties of both liquids and crystals and can in some cases transmit or reflect visible light better than liquid crystals themselves.

While researchers knew that this could be manipulated, they couldn’t manipulate the liquid directly; they instead placed droplets into a polymer film.

“That way we could encapsulate chiral liquid crystals and deform them in very specific, highly controlled ways,” de Pablo said. “That allows you to understand the properties they can have and what behaviors they exhibit.”

Researchers then found many more molecular configurations of the crystals than had been known before. These phases produce different colors based on how they are stretched or strained, or even when they undergo temperature changes.

“Now the possibilities are really open to the imagination,” de Pablo said. “Imagine using these crystals in a textile that changes color based on your temperature, or changes color where you bend your elbow.”

This system, the researchers argue, could be used to make smart coatings, for instance to measure strain in airplane wings or measure the temperature in a room.

“You could just look at the color of your device and know how much strain that material or device is under and take corrective action as needed,” he said. “For example, if a structure is under too much stress, you could see the color change right away and close it down to repair it. Or if a patient or an athlete placed too much strain on a particular body part as they move, they could wear a fabric to measure it and then try to correct it.”

   

Tagged categories: Coatings Technology; Coatings Technology; NA; North America; Research and development; Smart coatings

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