New boot sole rubber uses glass to grip on ice
At this time of year, people living in northern regions all over the world are faced with the same problem: icy sidewalks. Boots with otherwise grippy soles still slip, and spikes don't do well on stretches where there is no ice. Researchers from the Toronto Rehabilitation Institute and the University of Toronto are developing what could be a better alternative, however – rubber soles with bits of glass embedded in them.
The soles are made from slabs of thermoplastic polyurethane, that have tiny glass fibers in them running parallel to the surface. When those slabs are cut "across the grain" of the fibers, the result is smaller slabs that have the ends of the cut-through fibers protruding from them like miniature studs.
The polyurethane itself is flexible and rubbery, so it's still able to grip on hard dry surfaces such as asphalt. The tens of thousands of glass fibers, however, give it a sandpaper-like texture, letting it also "dig into ice on a micro-scale."
In order to test the material, the scientists utilized an elevated rig that can be slanted to simulate different degrees of ice-covered slopes. It was found that test subjects fared considerably better when using soles made from the material.
Although the soles should be relatively inexpensive to mass-produce using an automated process, the researchers are still working on boosting the durability of the material, as its slip-resistant qualities currently fade with repeated use.
A paper on the research was recently published in the journal Applied Physics Letters.
Source: American Institute of Physics