Materials

New boot sole rubber uses glass to grip on ice

New boot sole rubber uses glas...
The heel of this boot is made from the experimental new material (Photo: Toronto Rehabilitation Institute)
The heel of this boot is made from the experimental new material (Photo: Toronto Rehabilitation Institute)
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The heel of this boot is made from the experimental new material (Photo: Toronto Rehabilitation Institute)
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The heel of this boot is made from the experimental new material (Photo: Toronto Rehabilitation Institute)
The tiltable room used to test the material (Photo: Toronto Rehabilitation Institute)
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The tiltable room used to test the material (Photo: Toronto Rehabilitation Institute)

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."

The tiltable room used to test the material (Photo: Toronto Rehabilitation Institute)
The tiltable room used to test the material (Photo: Toronto Rehabilitation Institute)

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

6 comments
Gadgeteer
I've added nonslip patches to my heels for years. Clean the heels, apply Shoo Goo then press into coarse silicon carbide grit. Usually lasts all winter long.
lwesson
OUCH!
I am still recovering from a nasty fall on wet black ice of which my hiking boots did nothing but assist me in meeting Terra Firma, violently. As I lay painfully on the frozen ice and snow, I drifted off in my imagination as to how to make something like this a less frequent Winter activity. 12ºƒ kept me content to just lay there and drift nearly to sleep. Likely the cold assisted in damping the injured tissue. Thankfully, no broken bones!
the.other.will
This doesn't sound like something that can be worn indoors on anything other than carpet.
Mark Keller
Hey Iwesson! How about a bladder in the sole that when pumped up will push out retractable studs/spikes for added grip. Once at your destination you release the air and the spikes/studs go back into the soles.
MQ
Problem with the design.
Glass (even fibres) is very brittle, and with extended use the fibres will break off where they protrude from the polymer sole, soon rendering the glass reinforced sole nothing more than a plastic (polyurethane) surface to walk on, until the plastic wears down enough for the glass fibres to protrude again (the glass will wear faster than the plastic on a harsh surface due to the compliance of the polymer)... Starting the vicious cycle. Have they tried carbon fibres, aramid, silicon carbide (fibres), or even just embedding micro chunks of toungsten in (throughout the volume of the sole) the plastic etc., they have very high strength and are much tougher than glass, likely producing slower wear than the plastic substrate..
AS above, either coating shoes in grit (or manufacturing grit into the plastic/rubber sole), using removable spikes (for hiking boots) allowing traverse of varied terrain, or using appropriate spikes for the conditions (ice fishing is a no-brainer), is likely to be a better solution.
The "always" problem with removable spikes is that they may not be on the shoe when you unexpectedly need it (talk to my wife, and her fractured fibula last year).
Just gotta wear the right boots for the job.
We all (should) instinctively know that rubber soles and hard smooth ice don't really mix, this may be a soft-roader type of half way point for those who don't venture onto the slippery stuff too often. If you need spikes, then it should be spikes that you use.
And don't walk on the polished floor with your nails on, it scratches the hell out of the surface .
Rydog
This is nothing new. A company called Treksta has been doing this for a number of years.