Bouncy material remembers original shape

U. VIRGINIA (US) — Originally made to fix a wobbly table, a new type of silicone rubber is a “viscoelastic” solid—both rigid and fluid at the same time.

The material can be placed under a table leg where it conforms to the shape of the leg bottom and the floor surface, perfectly filling the gap.

In addition, the material may have applications as a packaging tape, as a shoe insole, as padding for prosthetics, as a handle material for canes, crutches, and sporting goods, and to make an assortment of toys.

It’s a bit like memory foam, but with strength and bounce.

“I was looking to come up with something cheap and simple to solve an everyday problem—wobbly tables—and ended up finding an amazing new material,” says University of Virginia physicist Lou Bloomfield. “I wanted something that could hold its shape while also being elastic.”

What he invented—he calls it “Vistik”—is the result of thousands of experiments conducted over about four years. Bloomfield tweaked his formula numerous times and came up with several different versions of the material for a variety of potential uses.

Sheets of Vistik bind together on contact, but separate easily when pulled apart. Bloomfield calls it the “molecular equivalent of Velcro.”

An interesting characteristic of the material is that while it sticks to itself, it does not stick to other materials and objects, and dust and dirt can be brushed off or washed away, allowing the material to easily re-adhere.

Vistik also regains its original shape after being compressed or imprinted. For example, a Vistik ball—which bounces like a super ball because of its elasticity—is soft enough that it can be squeezed into a flat disk that will slowly return to its round shape once the pressure is off.

That compliant, adaptive characteristic likely makes it an ideal material as a shoe insole or contact point for canes, crutches, and prosthetics.

“It takes an imprint, conforming to the shape of, for example, a foot, but then returns to its original shape, which can be flat or any shape we design,” Bloomfield says. “The material can even take imprints as fine as fingerprints.” He says he would like to someday see Vistik used as an insole for every shoe.

The material is so adaptive, Bloomfield says, it can be made bouncy or not so bouncy, and it tolerates a range of temperatures and is chemically inert.

“It’s tasteless, too,” he adds, “I can tell you that.”

Beyond its potential practical uses, Bloomfield imagines that Vistik someday could be made into toys, such as balls with different bounce rates like baseballs or tennis balls.

Currently, MeadWestvaco Corporation, a Richmond, Virginia packaging company, is investigating ways to use Vistik as a resealable adhesive for packages. Bloomfield imagines it as someday being a replacement for the plastic zip strips used on plastic storage bags.

Bloomfield is also working closely with the University’s Licensing & Ventures Group to bring his discovery to the public.

Source: University of Virginia