My first draft

 

geCKo Materials, a company that is producing artificial gecko material, came out of Professor Mark Cutkosky’s lab in Stanford. It is an adhesive that is inspired by the way geckos can scale walls and move about on the ceiling. The key feature of this adhesive is that it mimics the gecko’s foot structure, which allows it to cling to almost any rough or smooth surface. If a toe from a gecko’s is placed under a microscope, it can be observed that it is made up of very fine structures called spatulas which are less than one micrometre across. Although currently it is impossible to replicate this intricate branching structure, the tape makes use of a crude approximation of it. Instead of spatulas, the tape is covered with rows of sharp silicon wedges with tips that are around one micrometre. Unlike how sticky tape works, where the tape sticks due to the chemicals found on one surface of the tape, gecko adhesive is a dry adhesive that is easy to remove without the use of force at all and it leaves no marks or residue.

Drawing inspiration from the remarkable adhesive capabilities of gecko feet, geCKo Materials are poised to revolutionize adhesion in the future as it offers various industries with effortless, sustainable and ultra strong solutions to their different bonding needs.

The gecko material is designed with biomimicry in mind. Mimicking the one-of-the-kind structure of gecko feet, it relies similarly on Van der Waals forces for adhesion. These forces can be relatively strong under certain circumstances as they are able to influence interactions between molecules. The basic idea of the forces is that they become stronger as molecules come closer together and the larger the surface area of contact. Although Van der Waals forces are generally weaker compared to other chemical bonds like ionic and covalent bonds, it does offer several advantages.

 

For the material to have Van der Waals forces to work with and have adhesion, a force must be pulled parallel to the surface. The silicon wedges of the material will then all bend over and contact the surface, creating an almost continuous contact area. If it is pulled in any other way other than allowing the wedges to bend, it will not stick.

 

This unique way of sticking gives it the advantage of a secure attachment to the object or surface but at the same time an effortless release of said surface. As stated by Professor Mark Cutkosky, “that’s important because if you’re a small robot trying to climb a wall, you can’t afford to have something like chewing gum on your feet, cause then every step you take is effort. What you want is something that only grabs when you need it to.” (Muller, 2023, 1:30)

 

Relying on just Van der Waals forces, it will not leave behind any sticky remnants after it has been removed, meaning that the material can be reuseable. In their website it is stated that it “can be reused 120,000 times without performance loss” (geCKo Materials, 2023). The reusability of the material will not only save costs, but also acts as a more sustainable alternative to typical adhesives as it eliminates the need for consumers to repeatedly purchase the material.

 

How much weight the material can support is dependant on how much of the adhesive is in contact with the surface. “One square inch of contact area can support the weight about four-and-a-half kilograms.” (Muller, 2023, 8:08) Stanford made a robot called MicroTug, that just weights 17 grams and with the use of gecko adhesive, it was able to pull a weight that is 1200 times (20kg) of itself. To put it in perspective, it would like a human tugging a blue whale.

 

However, to create this special adhesive, it takes a long process. Firstly, to fabricate the micro wedges, a razor blade is drove into a wax mold at a specific angle. Then, a silicon polymer called Sylgard 170 is pouring into the mold with a backing material attached. Lastly, its cured at 23°∁ for 24 hours. Also, the mold can only be used a few times before the quality of the adhesive declines and the same steps are then repeated.

 

In conclusion, while the development and production for the gecko adhesive is arduous, the advantages that it provides overweight them. The ability to harness Van der Waals forces opens doors to diverse applications across numerous industries, from handling delicate produce to even assisting astronauts, redefining our approach to adhesion.

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References

 

geCKo Materials. (2023) https://www.geckomaterials.com/

 

Muller, D. [Veritasium]. (2023, Jan 23). The Stickiest *Non-Sticky* Substance [Video]. Youtube. https://www.youtube.com/watch?v=vS0TuIPoeBs&ab_channel=Veritasium

 

Russell, A. P., Stark, A. Y., & Higham, T. E. (2019). The integrative biology of gecko adhesion: historical review, current understanding, and grand challenges. Integrative and comparative biology.  https://par.nsf.gov/servlets/purl/10118696