Ultra-grippy shoes have been developed using a form of origami by researchers at the Massachusetts Institute of Technology.
Experts used kirigami, an artform involving the intricate cutting and folding of sheets of paper into three-dimensional structures, to create detailed patterns of spikes in sheets of plastic and metal.
The sheets, which are applied to the bottom of a shoe, stay flat while the wearer is standing, but the spikes pop up once they start to walk.
In the tests, they found that when people wearing shoes with a kirigami coating on the soles walked on an icy surface, the friction was up to 35 per cent stronger than uncoated designs.
It is hoped the friction-enhancing material could be used to limit dangerous falls on hazardous surfaces among the elderly in the future.
Sahab Babaee, the Lead author, said: "The novelty of this type of surface is that we have a shape transition from a 2D flat surface to a 3D geometry with needles that come out. You can use those elements to control friction because the sharp needles can pop in and out based on the stretch that you apply."
Kirigami, a form of the Japanese art of paper folding, has previously been used to create innovative materials such as bandages that stick more tightly to joints and sensors for robots.
In the MIT experiment, the researchers cut different patterns of spikes, such as squares, triangles and curves, into plastic sheets and stainless steel.
They measured the stiffness and the angle at which the spikes popped out when the material was stretched.
Researchers also calculated the friction produced by each design on a range of surfaces, including artificial turf, ice, vinyl flooring and wood.
Though all the designs increased friction, a pattern of concave curves generated the best results.
The concave curve coatings were then attached to a variety of shoe types, including trainers and winter boots, for volunteers to walk in across a 'force plate'-which measures the forces applied on the ground- covered with a one-inch thick layer of ice.
The amount of friction produced was between 20 to 35 percent greater with the kirigami coatings attached than the friction generated just by the shoes.
Researchers are now considering attaching kirigami surfaces onto the soles of shoes, or creating them as a distinct element that could be attached when necessary.
The study was published in the journal Nature Biomedical Engineering.