Anyone walking on icy or slippery surfaces.
Inspired by kirigami — a variation of origami (the Japanese art of paper cutting) that involves cutting paper as well as folding it — a new friction-boosting material could be used to coat the bottom of shoes, giving them a stronger grip on ice and other slippery surfaces. Kirigami involves cutting intricate patterns into sheets of paper and then folding them to create three-dimensional structures. The approach was used to create intricate patterns of spikes in a sheet of plastic or metal. These sheets, applied to the sole of a shoe, remain flat while the wearer is standing but the spikes pop out during the natural movement of walking. Designs included repeating patterns of spikes shaped like squares, triangles, or curves. While all of the designs boosted friction, the best results were produced by a pattern of concave curves. The coating was applied to different types of shoes including sneakers and winter boots. With the kirigami coatings attached, the amount of friction generated was 20 to 35 percent higher than the friction generated by the shoes alone.
Massachusetts Institute of Technology, Cambridge
The researchers are now working on determining the best way to attach and incorporate the kirigami surfaces including embedding them into the soles or designing them as a separate element that could be attached when needed. They are also exploring the possibility of using different materials such as a rubber-like polymer with a reinforced steel tip. They are looking at potential routes to commercialize the system.
Incorporating this coating into shoes could help prevent dangerous falls on ice and other hazardous surfaces, especially among the elderly. While the original motivation was preventing slips on icy surfaces, the researchers expect that this kind of shoe grip could also be useful in other settings such as wet or oily working environments.