Throughout history, people have been mimicking nature in various forms such as dance, paintings, song, and martial arts, highlighting the interconnectedness between the natural world and human culture. In addition to culture, nature has also influenced technology. The concept of biomimicry, originally coined biomimetics and first recorded by Leonardo Da Vinci in the mid-15th century, involves drawing inspiration from nature to develop technology and solve problems. Let’s take a look at five unique instances of biomimicry and discover what nature has to offer!
1. The Shinkansen Train
It’s not unreasonable to say that the high-speed Shinkansen train, more commonly known in English as the bullet train, was a revolutionary piece of Japanese infrastructure. The railway has numerous benefits, such as reducing congestion in cities, an economic contribution of 500 billion yen (roughly 3.3 billion US dollars) per year, improving housing affordability for Japanese citizens, and greatly reducing the CO2 output from Japanese cities. However, this is not to say that the almost 3000 km line hasn’t had its challenges.
Seven different trains on the JR East Shinkansen line, each featuring different designs. Licensed under CC BY-SA 3.0, via Wikimedia Commons.
One of these challenges is noise pollution. As the trains increased in speed, they would produce more noise, especially when entering tunnels. When in a tunnel, the high speed of such a train would push air to its front, compressing it. As the train and the wave of air reached the end of the tunnel, a loud sonic boom was created, disrupting residential areas. In an effort to reduce this effect, the pantographs in these trains were reduced and noise barriers were implemented, but it wasn’t enough.
However, this all changed when engineer Eiji Nakatsu found inspiration in an unlikely source — the kingfisher bird. After observing how gracefully the bird was able to dive into water without causing much disruption to the surface, Nakatsu decided to design a new train to mimic the properties of the bird. By redesigning the front of the Shinkansen train to look like a kingfisher’s beak, his team was able to reduce the train’s noise levels, lowered its energy consumption, and improve its overall speed.
The Common Kingfisher, also known as the Eurasian Kingfisher hovering. Note the thin cone-shaped beak. Licensed under CC BY-SA 3.0, via Wikimedia Commons.
2. Lotus-Effect Paint
While there is something satisfying about pressure washing away layers of dirt and grime off of concrete flagstones or building walls, it would certainly be amazing if we didn’t have to. If only there were a way to make it so that these surfaces could clean themselves. Luckily, engineers have done exactly that by looking toward the lotus plant and its interesting leaves for inspiration.
Lotus plants displaying their ultrahydrophobic properties. Licensed under CC BY 3.0, via Wikimedia Commons.
While the ultrahydrophobic properties of the lotus plant have been observed for a long time, their unique properties were first identified by Dr. Wilhelm Barthlott in the 1970s. Coined the “lotus effect”, the plant’s ultrahydrophobic properties mean that only 0.6% of any water droplets on the leaf stick to the surface. This is due to the tiny rough texture on the leaf, which traps air in minuscule cavities on the leaf’s surface, causing water to slide right off and dragging any dirt or dust particles off the leaf as the water falls. This self-cleaning and ultrahydrophobic effect immediately appealed to engineers across multiple fields.
A water droplet on the surface of a lotus leaf, with contact angles highlighted. Licensed in the public domain, via Wikimedia Commons.
After discovering this effect, Barthlott began researching how to mimic these properties in an industrial setting, eventually developing a coating that is used on buildings throughout Europe to reduce dirt and grime buildup. Other scientists mimicked the effect to create hydrophobic textiles and self-cleaning metals. In addition, NASA has used the effect to design self-cleaning space suits, scientific instruments, and solar array panels.
3. Wind Turbines
People have been harnessing the power of wind as early as we have had sailing ships. In fact, the first windmill was developed in the 9th century. Windmills found usage all across the world, and eventually the first wind turbine was built in Scotland in the late 1880s, allowing us to turn wind into electricity. With rising climate concerns, wind power is growing increasingly popular. An important innovation in the world of wind power comes not from the sky, but from the sea, as researchers look to the humpback whale to increase efficiency in wind turbines.
A wind farm in Xinjiang, China. Licensed under CC BY-SA 2.0, via Wikimedia Commons.
Researchers discovered that the humpback whale, despite its large size, is capable of surprisingly acrobatic actions — such as rolls, tight turns, and breaching — partly due to the unique bumps on its fins known as tubercles. These tubercles are bumps that grow on the leading edge (the part that first contacts the air, or in this case water) of a humpback’s fin and have been shown to channel air into narrow streams along the fin, reducing drag and increasing lift. This is known as the tubercle effect.
A humpback whale breaching in the Stellwagen Bank National Marine Sanctuary in Massachusetts. Notice the bumps on the front edge of the whale’s fin. Licensed under CC BY 3.0, via Wikimedia Commons.
Engineers have started testing the benefits of the tubercle effect in a variety of different applications, including aircraft and wind turbines. Research found that tubercles can make it harder for an aircraft to stall, effectively increasing the angles that the blades of an aircraft can function at. When applied toward the blades of wind turbines, the inclusion of tubercles allows them to function at much lower wind speeds, reduce the noise produced by their spinning blades, and improve their angles of operation, which keeps the turbines effective in unpredictable weather conditions.
4. Nano Tape
People have needed to stick things together for as long as we have been around, with evidence of tar adhesives being used for early stone tools dating back to the Middle Paleolithic era. Adhesives have come a long way since then. Whether you are using super glue to connect broken plastic or placing a sticky note on a boardroom wall as a reminder, adhesion comes in many forms and strengths. There is even one such form that doesn’t need to be sticky at all: fully nonchemical adhesive tape, inspired by geckoes and their unique ability to climb sheer surfaces.
A close-up view of the underside of a gecko’s foot sticking to a glass wall. Licensed under CC BY 3.0, via Wikimedia Commons.
To stick to surfaces, geckoes use a phenomenon known as van der Waals forces, which describe the attraction and repulsion between atoms. Unlike ionic or covalent bonds, van der Waals forces do not exist because of a chemical bond. These forces are typically weak, but many other animals, such as insects and spiders, also use these forces to climb. Like the gecko, these animals each have a massive array of tiny hairs called setae on their legs, allowing them to stick onto sheer surfaces, like glass. By mimicking the tiny hairs on a gecko, scientists were able to develop a tape using these forces, which allows objects to be suspended without any chemical adhesives.
A microscopic view of nano tape. Licensed under CC BY 3.0, via Wikipedia.
This tape, often called nano tape, uses carbon nanotubes to mimic the setae on a gecko’s footpad, which allows the tape to stick surfaces together by using the same van der Waal’s forces that a gecko does. Originally developed in the early 2000s, advancements have been made to the technology to allow the tape to stick stronger, be removed more easily, and even be used in robotics. (Tip: If you want to learn more about how geckoes use van der Waals forces to climb, check out our Gecko Foot model!)
5. Synthetic Spider Silk
While most people think spiders are the work of nightmares, it’s well known that spiders have many benefits. Their hunting of insects keeps pest populations in check and reduces the spread of disease, their venom is being studied for use in treating chronic pain, and their ballooning behavior can be studied to further understand population dynamics. One benefit comes in the form of a spider’s silk, which is durable, highly elastic, and extremely lightweight.
A spider wrapping its prey in silk. Licensed under CC BY-SA 4.0, via Wikimedia Commons.
So, if spider silk is so amazing, why aren’t we using it? The first problem is that it is extremely difficult to produce. Unlike silkworms, spiders are both predatory and solitary animals, which makes them challenging to farm through typical methods. In addition, it takes a very long time to gather, with the largest piece of spider textile taking artists five years and a million spiders to produce a single shawl. Due to these challenges, engineers have turned to artificial methods to try and create spider silk.
When a spider produces silk, they first create a complex and protein-dense liquid in an internal silk gland. As this liquid moves through the spider’s body, it enters ducts that acidify it and turn it into a solid strand. The strand is then pulled through a spinneret and used for a variety of applications, like trapping prey or building nests. When trying to recreate this process, there are a variety of challenges. First, the liquid that a spider turns into silk is difficult to reproduce due to its long and complex molecular structure. Second, the liquid must then be turned into a solid silk, which can require lots of energy or harmful chemicals, like methanol and acetone. Third, the silk must then be carefully stretched (or spun) to produce usable fibers. Regardless of the method, producing usable faux silk is costly and inefficient.
A piece of artificial spider silk developed in a lab. Licensed under CC BY 3.0, via Wikimedia Commons.
However, not all hope is lost, as researchers continue to make strides in producing artificial silk through both bioengineering and bioinspired synthesis. Steps are already being made to produce these fibers without high costs or harmful environmental impacts. Who knows, some day we might be walking around in spider-spun shirts, climbing with ropes of spiderweb, or getting our wounds stitched with sutures made from spider silk.
Further Reading
Interested in learning more about how technology and nature intersect? Check out these posts on the COMSOL Blog:
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