By: Gabe Cherry Of Michigan News
In an advance that could grime-proof phone screens, countertops, camera lenses and countless other everyday items, a materials science researcher at the University of Michigan has demonstrated a smooth, durable, clear coating that swiftly sheds water, oils, alcohols and, yes, peanut butter.
Called “omniphobic” in materials science parlance, the new coating repels just about every known liquid. It’s the latest in a series of breakthrough coatings from the lab of Anish Tuteja, U-M associate professor of materials science and engineering. The team’s earlier efforts produced durable coatings that repelled ice and water, and a more fragile omniphobic coating. The new omniphobic coating is the first that’s durable and clear. Easily applied to virtually any surface, it’s detailed in a paper published in ACS Applied Materials & Interfaces.
Tuteja envisions the new coating as a way to prevent surfaces from getting grimy, both in home and industry. It could work on computer displays, tables, floors and walls, for example.
“I have a 2-year-old at home, so for me, this particular project was about more than just the science,” Tuteja said. “We’re excited about what this could do to make homes and daycares cleaner places, and we’re looking at a variety of possible applications in industry as well.”
He says the new coating is the latest result of the team’s systematic approach, which breaks with the traditional materials science “mix-and-see” approach. By mapping out the fundamental properties of a vast library of substances, they’re able to mathematically predict how any two will behave when they’re combined. This enables them to concoct a nearly endless variety of combinations with very specifically tailored properties.
“In the past, researchers might have taken a very durable substance and a very repellent substance and mixed them together,” Tuteja said. “But this doesn’t necessarily yield a durable, repellent coating.”
They discovered that even more important than durability or repellency is a property called “partial miscibility,” or the ability of two substances to mix together in exactly the right way. Chemicals that play well together make a much more durable product, even if they’re less durable individually.
Tweaking the miscibility of this particular coating posed a special challenge. To make a versatile coating that’s optically clear and smooth enough to repel oils and alcohols, the team needed to find a repellent ingredient and a binder with exactly the right amount of miscibility, as well as the ability to stick to a wide variety of substrates. They also needed a coating that would stay smooth during processing and drying.