Reader response draft 4

Gecko-inspired adhesive came out of Professor Mark Cutkosky’s lab at Stanford and is now marketed as geCKo Materials (Muller, 2023). Imagine a material that can seamlessly adhere to almost any surface, strong enough to hold a human's weight on a smooth wall yet gentle enough to leave no residue. geCKo Materials is inspired by the incredible way geckos can scale walls and even move about on the ceiling. According to Hawkes et al. (2015), it mimics the gecko’s foot structure, allowing it to cling to almost any surface be it rough or smooth due to it being able to make close contact with the surface. This field is a rather young one as it was born out of discovering the mechanism of adhesion from geckos in 2002, namely Van der Waals forces. 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. Although it is currently impossible to replicate the intricate branching structure of a gecko’s foot, the tape uses a crude approximation of it.

The groundbreaking material that geCKo Materials has presented represents a promising avenue for innovation in material science, offering versatile, sustainable, and durable solutions for adhesion across various industries. However, its widespread implementation faces challenges related to scaling up production and ensuring long-term wear resistance.*

Gecko-inspired materials present many advantages, primarily from their great versatility, and they have the potential to change the adhesive industry. Research by Sitti and Fearing (2003) showcases that gecko-inspired materials can adhere to a large range of surfaces, from rough to smooth, without leaving any kind of residue behind. This characteristic of gecko- inspired materials makes it especially versatile for a diverse range of applications, from biomedical to even industrial settings. For example, gecko- inspired adhesives have shown potential in medical applications such as wound closures and “tissue engineering scaffolds” due to their unique ability to adhere to biological surfaces without damage and unwanted residue (Mahdavi et al., 2008). Additionally, for industrial contexts, gecko -inspired materials also offers great potential in robotics assembly, where it can be used to pick up delicate objects in the production line for assembly and packing, or in manufacturing and assembly where traditional adhesives may be at a disadvantage in terms of versatility and efficiency (Muller, 2023, 10:00).

Additionally, gecko-inspired materials' sustainability is very noteworthy. Kerst and Salfity (n.d.) highlight that gecko-inspired adhesive materials are reusable with Autumn et al. (2000) stating that they do not rely on harmful chemicals, known as dry adhesives, as such traditional adhesives rely on chemicals to get their adhesive properties. The

Sustainability factor is becoming more important in today's context as consumers are looking for greener alternatives to traditional products. This, in turn, pushes the industry to look for eco-friendly and reusable solutions. By drawing inspiration from nature, gecko-inspired materials will contribute to the rise in environmentally friendly products and solutions that would reduce the carbon footprint and in turn minimize environmental impacts.

However, the widespread usage of gecko-inspired materials still faces significant challenges. One of the most notable challenges is the scalability of its production. Geim et al.(2003) states that the current manufacturing techniques for these materials still need to be matured and thus are not suitable for large scale production, which limits its commercial viability. Scaling up the production of gecko-inspired materials while maintaining its unique characteristics poses an engineering feat which would require future innovative approaches and technological advancements. Addressing this challenge would be the key to unlocking the full potential of gecko inspired materials and its usage in different various industries on a mass scale (Geim et al.,2003).

Another major drawback of gecko-inspired materials is their long term wear resistance. Wang et al. (2021) observed that the adhesive properties of gecko materials may degrade overtime, reducing their durability and usefulness in the long run. This degradation is due to environmental conditions, surface roughness of the material the gecko adhesive is used on, and mechanical stress. Addressing this degradation would require research and development into it in the form of material design, surface engineering or even coatings. This would enable gecko-inspired materials to withstand prolonged use in harsh environmental conditions, which is essential for their reliability and performance in wide practical usage in the long term.

In conclusion, there is sufficient evidence to prove that gecko-inspired materials holds an immense promise of being a versatile and sustainable solution for adhesion across industries in the future. Their unique characteristics offer opportunities in a wide range of industries like robotics, biomedicine and manufacturing. However, addressing the challenges related to scalability and reusability in the long term is paramount in unleashing its full potential. Overcoming these challenges would increase gecko-inspired materials ‘ potential to revolutionize the field of adhesion and contribute to a greener and more sustainable environment.

References

Autumn, K., Sitti, M., Liang, Y. A., Peattie, A. M., Hansen, W. R., Sponberg, S., Kenny, T. W., Fearing, R., Israelachvili, J. N., & Full, R. J. (2002). Evidence for van der Waals adhesion in gecko setae. Proceedings of the National Academy of Sciences. https://www.pnas.org/doi/10.1073/pnas.192252799

Geim, A. K., Dubonos, S. V., Grigorieva, I. V., Novoselov, K. S., Zhukov, A. A., & Shapoval, S. Y. (2003). Microfabricated adhesive mimicking gecko foot-hair. Nature Materials. https://www.nature.com/articles/nmat917

Hawkes,E.W.(2015). Human climbing with efficiently scaled gecko-inspired dry adhesives. Journal of the Royal Society Interface, 12(102) pages? https://royalsocietypublishing.org/doi/full/10.1098/rsif.2014.0675

Kerst,C., & Salfity, J.(n.d.). geCKo Materials Executive Summary. Stanford.https://web.stanford.edu/group/OTL/lagan/19334/geCKO%20for%20Stanford.pdf

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

Mahdavi et al., (2008). A biodegradable and biocompatible gecko-inspired tissue adhesive. Proceedings of the National Academy of Sciences USA, 105(7) pages? Https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2268132/

Sitti, M., & Fearing, R. S. (2003). Synthetic gecko foot-hair micro/nano-structures as dry adhesives. Journal of Adhesion Science and Technology. https://www.cs.cmu.edu/afs/cs/academic/class/15398-f04/www/readings/p1055.pdf

Wang,W., Liu,Y., & Xie,Z.(2021). Gecko-like dry adhesives and their applications. Springer Nature. https://link.springer.com/article/10.1007/s42235-021-00088-7