Scientists come up with Geckskin, a reusable adhesive.
A TEAM of scientists at the University of Massachusetts has developed a new, reusable adhesive based on the feet of the gecko – the lizard that licks its own eyeballs and climbs up walls. Around 60% of gecko species have adhesive toe pads and these pads were the inspiration for Geckskin, a device that can attach and detach from materials and surfaces repeatedly.
Led by professor of polymer science and engineering Al Crosby and professor of biology Duncan Irschick, the team designed Geckskin for performance – you can suspend up to about 320kg in weight with it and it can be made from everyday items such as nylon, bathroom caulking, carbon fibre or cotton.
Most things adhere to it and it adheres to most things. It’s like flypaper for elephants.
Crosby and Irschick say it’s not about making a new material but making old materials perform in new ways. Geckskin is detachable and attachable.
Its inventors stress its high weight capacity. What stops a TV you are hanging up from crashing down is the math. “Geckskin is built around three parts: pad, skin and tendon,” explains Crosby. “The way we configure the tendon and the skin allows us to design how it will be removed - so there will only be one mechanism or one twist that will take off the pad. Everything else would be stabilised. If you were to bump into that TV, it wouldn’t come off unless you twist it purposefully in one way. It’s very stable to things like accidental bumps or wind.”
A key property of certain types of gecko is the ability to attach to any surface, release at will and be able to hold a significant amount of weight. Crosby’s group has worked on gecko-inspired adhesion for almost 12 years. “About five years ago, we started asking what allowed nature to scale adhesion,” continues Crosby. “Then we started developing the math behind Geckskin.”
Given that there is usually a defence interest in innovation, where did they get their money from? “We had some Darpa funds,” Crosby says (Darpa is the advanced research arm of the US Defence Department). “We also had a lot of National Science Foundation funding prior to that.”
The transition between a military application towards a commercial or industrial application is intriguing. Airbags and types of insulation started out this way, as have many other seemingly innocuous products like superglue.
What about the life cycle environmental impact of things? Crosby says he’s only able to give qualitative answers to that and that they’re still trying to figure out the quantitative sides of it. “The original materials are everyday ones like things used in bathroom caulking and carbon fibre,” Crosby says. “We’re still using the same ones today that we made five years ago – it has a very long life cycle.”
“Recently, we’ve made Geckskin out of 100% renewable resources – natural fibres as well as natural rubber – and still have high performance,” Irschick adds. “Our way of looking at it is that now we can eliminate waste though extended wear. Adhesives are often just one use; you can put these things in the washing machine, reuse them. We think that’s significant.”
"In order to get the strength you get from Geckskin, you need to use epoxies and structural adhesives to bond two things together,” explains Crosby. “You can’t easily break those apart. With Geckskin, you get a strong bond but you can disassemble it. It eliminates adhesive waste but can also eliminate material waste.”
Geckskin is different from other gecko-inspired adhesives, most of which tend to be nanotechnology-based and require complex manufacturing techniques. “We aren’t creating a new material that requires some crazy nanotechnology and is going to cost millions to produce,” says Irschick. “The creation is simple in its conception and profound in the way it’s put together.”
The team has won a number of awards for the simplicity of its manufacturing process or the way the materials piece together. After the release of their first publication on the material, up to 80 companies contacted them wanting a piece of the pie. They still get around one or two companies a week approaching them.
Crosby continues: “The math behind Geckskin said that we can use almost any material to achieve this performance. That opened up our eyes and we started using materials that have less environmental impact. Geckskin 2.0.”
Geckskin is still being developed. Crosby, Irschick and another partner estimate that they have at least a year until they have something ready to go on the market.
There’s more. They have yet to explore the biomedical uses of Geckskin in terms of using it to bond skin. Geckskin 3.0? Why not? – Guardian News & Media