A materials science researcher at the University of Michigan has demonstrated a smooth, durable, and transparent coating that quickly separates water, oil, alcohol, and even peanut butter, making the phone screen, countertops, camera lenses, and many other commodity surfaces resistant. Stains.

This superhydrophobic coating is called "omniphobic" in material science terminology and it almost repels all known liquids. This is the latest breakthrough in the coating process of Anish Tuteja, an associate professor of materials science and engineering at the University of Michigan. The team worked early on to create durable coatings that repel ice and water, as well as more fragile super-lyophobic coatings. This new super lyophobic coating is the first coating that is both durable and clean. This coating is used on almost any surface, and the study was published in the Journal of Applied Chemistry and Interfaces of the American Chemical Society.

Tuteja envisions this new coating to prevent the surface of objects from getting dirty, whether in the home or in an industrial setting. For example, it can be applied to computer monitors, tables, floors, and house walls.

“I have a two-year-old child at home. For me, this special project is more than just science,” Tuteja said. “We are very happy to be able to do this to make families and nurseries cleaner, and we are also researching various possible applications.”

He said that the new coating is the latest in the team's system approach, breaking the traditional “mix and observe” approach to materials science. By plotting the basic properties of a large library of materials, the team can mathematically predict the behavior of any two substances when combined. This allows them to modulate almost infinite combinations with custom-tailored properties.

“In the past, researchers have taken extremely durable materials and extremely waterproof materials and mixed them together,” Tuteja said. “But this does not necessarily produce a durable waterproof coating.”

They found that 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. Even if the less durable chemicals are used alone, the products that are mixed together will be more durable.

Adjusting the miscibility of this particular coating is a particular challenge. To create a versatile coating that removes grease and alcohol well, the team needed to find repellent ingredients and binders with the right miscibility and ability to adhere to a variety of substrates. They also need to keep the coating smooth during processing and drying.

“You can repel water with a rough surface because it creates tiny air holes between the water and the surface, but because of the low surface tension, these surfaces don't always repel grease or alcohol,” Tuteja said. “We need a very smooth surface that interacts as little as possible with the various liquids, and we also need very good mixing materials because the phase separation between the raw materials is too large to scatter light”.

In the end, the team found a blend of fluorinated polyurethanes and a special insect repellent called F-POSS. Their formulation forms a mixture that can be sprayed, brushed, dipped or spin coated onto a variety of surfaces and tightly bonded together. Although the surface can be scratched by sharp objects, it is very durable in everyday use. In addition, its extremely accurate phase separation level makes it optically clear.

Mathew Boban, a graduate student and paper thesis in materials science and engineering, said: "This insect repellent and binder are mixed together to form a clear coating, but there is very little phase separation between them. This separation makes F- POSS floats to the surface and forms a good repellent layer."

Tuteja believes that this coating price will be very cheap when entering the mass market. Fluoropolyurethane is already a cheap common raw material. Although F-POSS is now very rare and expensive, manufacturers are expanding their production scale, which will greatly reduce costs.

The research team is still conducting further research to ensure that the paint is non-toxic in places such as day care centers. Tuteja estimates that paints may enter the market within the next two years, and he believes that protecting children's paint is only the beginning.

The coating can also be used in refrigeration, power generation and refining – all industries that rely on liquid condensation. The new coating allows the unit to decompose condensate and chemicals more quickly, with a 20% increase in efficiency. For the world's highest-yielding, highest-energy industries, this is a game changer.

Original text from materialstoday website, the original title: New coating repels everything from water to peanut butter , this article by material technology online finishing reports.

Original article:

Smooth, All-Solid, Low-Hysteresis, Omniphobic Surfaces with Enhanced Mechanical Durability