Researchers from Canada are developing new methods to mass-produce a material that may help pedestrians get a better grip on slippery surfaces. The material, which is made up of glass fibers embedded in a compliant rubber, could one day be used in the soles of slip-resistant winter boots. The researchers describe the manufacturing process in a paper in the journal Applied Physics Letters, from AIP Publishing.

"I think anyone who has slipped or fallen on ice can testify that it is a painful or nerve-raking experience," said Reza Rizvi, a postdoctoral fellow at the Toronto Rehabilitation Institute who works on developing materials that can provide better traction on ice. "Now imagine being frail or disabled, a slippery sidewalk or a driveway is all that it takes to trigger a life-changing fall. A serious fall on ice resulting in a hip fracture can be a death sentence for an older adult.” Rizvi and his colleagues, including Hani Naguib from the Smart and Adaptive Polymers Lab at the University of Toronto, have developed a new method to manufacture a type of rubber that “digs in” on the micro-scale. The material is made up of thermoplastic polyurethane, a rubbery plastic, embedded with tens of thousands of tiny glass fibers that protrude out of the rubber like microscopic studs and give the material the feel of fine sandpaper. The material looks like regular rubber and will stretch and deform in similar ways, said Rizvi. The material also performs just as well as regular rubber on dry surfaces such as quarry tile, he added. But on ice the rubber-glass fiber composite provides significantly better traction.

Existing methods for fabricating the material require first extruding a rubber slab with glass fibers running parallel with the surface. The slab is then cut and reoriented so that the fibers stick out of the surface like the pins in a pincushion. "The materials required for creating a high friction composite are not expensive, but the process of slicing and rearranging the rubber is not easily scalable," Rizvi said. The team has found a way to automate the process so that the material could be cheaply mass-produced. The team noted that there is further work to be done to improve the wear-resistance of the material. Their testing has shown that the slip-resistant properties of the material fade with use so it would not be appropriate for commercial footwear until its robustness is improved.

Source: rubberworld.com