Physicist Louis Bloomfield, PhD, a physics professor at the University of Virginia (U.Va), Charlottesville, has invented a type of silicone rubber that is both rigid and fluid-a viscoelastic solid-with compliant, adaptive characteristics that may make it an ideal material for contact points in prosthetic devices, shoe insoles, canes, and crutches.
Physicist Bloomfield with Vistik. Photograph courtesy of Dan Addison, University of Virginia.
The material, dubbed Vistik, is so adaptive, Bloomfield said, that it can be made bouncy or not, it regains its original shape after being compressed or imprinted, it tolerates a range of temperatures, and it is chemically inert and tasteless. Vistik sticks only to itself, and dirt and dust can be brushed off or washed away, allowing the material to easily re-adhere.
For example, a Vistik ball bounces like a super ball because of its elasticity, but is soft enough that it can be squeezed into a flat disk that will slowly return to its round shape once the pressure is removed. “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,” Bloomfield said. “I wanted something that could hold its shape while also being elastic.”
Bloomfield is working with the U.Va. Licensing and Ventures Group, part of the U.Va. Innovation initiative dedicated to technology commercialization, to bring his discovery to the public. Vistik is currently being investigated by a packaging company as a resealable adhesive for packages. Bloomfield calls it the “molecular equivalent of Velcro” because sheets of Vistik bind together on contact, but separate easily when pulled apart.
Yet it’s the compliant characteristics of the silicone rubber that make it most useful for prosthetic devices. “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 said.
Editor’s note: This story was adapted from materials provided by the University of Virginia.
