Unravelling the physics and mechanisms behind slips and falls on icy surfaces: A comprehensive review and nature-inspired solutions

Slip and Fall (SF) on slippery icy/snowy surfaces during winters is evident worldwide, especially in Nordic regions. Every year millions of people slip and fall due to ice accretion on the roads, streets, and pavements causing traumatic injuries, loss of limbs, and sometime loss of lives, costing billions in hospitals and recovery. An efficient anti-slipping winter shoe-sole could prevent these accidents and save lives. Footwear industries came up with solutions such like crampons, cleats, anti-skidding materials and tread pattern designs, but with limited success because of their ineffectiveness on wet ice, quick rate of wearing. The inspiration from nature like polar bear, seal, arctic fox, penguin, snake, octopus, frog, and gecko where this problem is elegantly solved through evolution process can address these limitations and design advanced anti-slippery surfaces. The review presents a comprehensive understanding of biological designs of the footpads (polar bear, penguin, arctic fox, frog, gecko) and skins (seal, snake, octopus' suction cups) and recent progress on their translation for practical applications. The review emphasises on the mechanisms of icy slippery surfaces and the contact surfaces (shoe-sole and ice/snow) to mimic anti-slipping mechanism of animals and their movement on ice enabling to design the finest anti-slipping winter shoe-soles.