Researchers at Stanford have developed gloves inspired by the climbing movement of geckos that give users under 200 pounds the ability to climb a smooth, vertical surface. Their research is published in this week's issue of the Journal of the Royal Society Interface.
Popular Mechanics' William Herkewitz discussed the project,
"Hawkes and his colleagues developed a dry-adhesive called PDMS microwedges. Unlike duct tape or super glue, this reptile-inspired adhesive works via clingy hair-like nanofibers. These nanofibers flatten out when pulled downward against a surface and grip via electromagnetic attraction (called the van der Waals force) but can be pulled off easily with a perpendicular tug.
Using springs, they anchored 24 microwedge patches to a flat plate that a person could grab with their hand, the idea being that the 24 patches distribute the force of a climber. However, this is actually a well-tested recipe for failure. Normal springs won't distribute weight as evenly as you'd need. Worse, when a single patch is pulled past its breaking point, the failure can avalanche across the entire plate.
Here's the key to Hawkes' system: Instead of using ordinary springs to anchor the adhesive patches, they used springs made of a shape-memory alloy. While normal springs become tenser as you pull them like a rubber band, the scientist's shape-memory alloy springs actually become softer and less tense, like stretching bubblegum.
Anchored by these weird springs, each of Hawkes' microwedges distributed the weight of a clinging climber across the plate with near perfection. Hawkes could easily scale a glass wall, and the scientists have calculated that the gloves could be used by anyone up to around 200 lbs. And if one wedge ever fails, the plate simply self-corrects."