Researchers of University of Massachusetts Amherst in the US developed Geckskin, a synthetic adhesive made with stiff fabric, which was inspired by geckos.

Geckos have the ability to climb vertical and overhanding walls, thanks to the millions of minute hairs called setae. These hairs act as a soft substrate that can conform to surfaces.

The research started when two researchers from entirely different fields came together. Duncan Irschick is a biologist who devoted over 20 years to studying geckos, while polymer scientist Alfred Crosby worked on polymer adhesion.

The research was based on the premises that if adhesives were made of stiff fabrics instead of a soft gooey material, the adhesive force could increase dramatically. The researchers found that geckos have stiff tendons attached to their toe pads, which act much like the stiff fabric adhesive.

The resulting material, called Geckskin, replies on a concept known as draping adhesion, unlike traditional pressure-sensitive adhesives, which rely on viscoelasticity. The adhesion is created with materials that can drape, to create contact with a surface while maintaining elastic stiffness in directions where forces will be applied. According to the researchers, “This design enables adhesive loads to be more evenly distributed across the pad surface, while also allowing for a rapid and low-energy transition between attachment and detachment.”

Geckskin is composed of stiff fabrics like carbon fibre or Kevlar, combined with soft elastomers such as polyurethane or polydimethylsiloxane (PDMS). The researchers also introduced a ‘green’ version, made from renewable materials. For this, they used natural rubbed impregnated into stiff natural fibre fabrics such as cotton, hemp and jute.

By integrating the soft elastomer (the pad) with a stiff fabric (the skin), the pad can be draped over a surface to maximise contact. Like an actual gecko foot, the skin is woven into a synthetic tendon, creating a design that plays a key role in maintaining stiffness and rotational freedom. The result is an adhesive device that is so powerful that an index-card sized piece can hold 700 pounds on a smooth surface, such as glass. The material can easily be removed, reused, and leaves no residue.

Photos: Geckskin