Episode 1: Leaves and Their Non-Stick Properties
Scratch... an intriguing material that everyone has played with, for example, when fastening their shoes. But who knew that scratch was inspired by burdock, and that it was by removing this seed from his dog's fur that George de Mestral decided to create the famous Velcro? That's what biomimicry is about. It's drawing inspiration from nature to learn from it, without destroying it. Today, we will observe the leaves of our friends the trees.
Drawing inspiration from tree leaves?
The leaves of trees have a unique surface composition. Who has ever seen a dirty leaf ? No one. That's because this surface prevents dirt, insects, or other pests from adhering to the leaf and therefore damaging or even destroying it. This characteristic has been a great source of inspiration for creating non-stick coatings, which are very useful in many fields.
Moreover, the true beauty of biomimicry lies in its ability to replicate what nature does while avoiding its destruction. It is "innovation with respect". And what could be more natural than a leaf ? Drawing inspiration from their non-stick properties, for instance, allows us to eliminate the use of harmful substances for the planet. This creates a virtuous circle where we first learn from nature and then innovate to protect it.
In addition to their anti-adhesive capacity, trees possess mechanisms that maximize the energy efficiency of their leaves, such as photosynthesis. By drawing inspiration from these mechanisms, it is possible to design solar panels inspired by the structure of leaves, resulting in better capture of solar energy.
And in practical terms, what does it look like?
The company Pilkington has developed a self-cleaning coating called "Activ." It is applied to glass windows and is inspired by the hydrophobic property of tree leaves, making cleaning easier and repelling water. Additionally, when in contact with this coating, water forms beads that roll off the glass surface, carrying away all the dirt. This keeps the windows constantly clean and prevents dirt from adhering. This glazing, primarily used for optimization and aesthetics, can also be extremely useful in areas where window cleaning can be dangerous, such as high-rise buildings and structures. Environmentally, it avoids the use of chemical cleaning products that are harmful to the planet.
Just as biomimicry is used in a wide range of fields, the leaf's inspiration extends beyond windows. Looking through it, we can admire the stars, but who would have imagined that the "Star Wars" launched by Reagan in 1983 was aided by the study of leaves? Indeed, Teflon, a fluoropolymer material that replicates the non-stick properties of leaves, also known as the "lotus effect," was used in this Cold War context.
To send the first satellites into space in the 1960s, it was necessary to find a material resistant to temperatures and conditions previously unknown in this environment. Teflon was chosen to cover the external surfaces of the satellites, creating a protective, anti-adhesive, and durable layer that prevents debris accumulation. After conquering space, Teflon's use diversified and reached our kitchens, in our pans and pots. However, this material is still used in the aerospace industry, propelling us toward new discoveries. After conquering the moon, our leaf-inspired material is now aiming for Mars.
To be continued...
Series of articles on biomimicry written by Clémence Alaux.
- Neinhuis, C., & Barthlott, W. (1997). Characterization and distribution of water-repellent, self-cleaning plant surfaces. Annals of botany, 79(6), 667-677.
- Vincent, J. F. V., & Bogatyreva, O. A. (2013). Biomimetics: Nature-Based Innovation. CRC Press.
- Yao, X., Song, Y., Jiang, L., & Wong, T. S. (2011). Bio-Inspired Surfaces with Special Wettability for Advanced Applications. Materials Today, 14(7-8), 334-348.
- POURQUOI LES FEUILLES SONT-ELLES IMPERMÉABLES? NOVEMBRE 17, 2020 RHIAN GRUER, right for education