Scientists have developed a new surface, which they call  “superomniphobic”, that can repel virtually any liquid, even the most troublesome like blood or highly concentrated acids. Their findings brings us a step closer to manufacturing stain-proof, spill-proof clothing, protective garments and other products.

Currently there is a wide range of clothing and garments that are water proof and offer protection against some spills, but even the most expensive and technologically advanced products, be them synthetics to waxed canvas, don’t stand a chance against low-tension liquids like ketchup or oils that soak right up into the fabric.

Superomniphobic surface

Acetic acid and hexylamine droplets bounce off the superomniphobic material.(c) Anish Tuteja / University of Michigan

In a breakthrough, researchers at Scientists at the University of Michigan have developed a superomniphobic surface  that displays extreme repellency to two families of liquids—Newtonian and non-Newtonian liquids.  Newtonian liquids are most common (water) and are basically liquids whose viscosity remains constant no matter the stress they’re subjected too. While surfaces that repel non-Newtonian fluids have been typically the object of research for most scientists, the Michigan scientists decided to tackle non-Newtonian liquids as well, which include blood, yogurt, gravy, various polymer solutions and a range of other liquids.

“Normally when people talk about superhydrophobic or superomniphobic surfaces, they talk about wetting, which is a measure of the shape that droplets make on the surface and their contact angles,’ says Sergiy Minko, who researches smart polymer materials at Clarkson University in Potsdam, US.

The omniphobic material's geometry and close-up structure. (c) Anish Tuteja / University of Michigan

The omniphobic material’s geometry and close-up structure. (c) Anish Tuteja / University of Michigan

Anish Tuteja and colleagues have developed a surface that repels both Newtonian liquids and oily ones – virtually all liquids easily roll off and bounce on the new surfaces, which makes them ideal for protecting other materials from the effects of chemicals. This was achieved by carefully building the surface such that it has a very low wetting hysteresis – contact angles  of the droplet is the same in both front and rear. This causes the droplet to roll over the surface  without leaking through the surface.

The material is based on a fine stainless steel wire mesh. This is coated with a layer of polymer beads, made from a mixture of polydimethylsiloxane (PDMS) and fluorodecyl polyhedral oligomeric silsesquioxane (POSS). Possible applications for this novel superomniphic surface include  stain-free clothing; spill-resistant, breathable protective wear; surfaces that shrug off microbes like bacteria; and corrosion-resistant coatings.




Findings were reported in the Journal of the American Chemical Society.

via Chemistry World

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