I’ve always been drawn to what we call “earth colors”—soft browns, olive greens, muted oranges, dusty pinks and corn-husk yellows. Colors have been on my mind because I recently moved to the Pacific Northwest into an older home that needs paint and some new carpeting. I find myself attracted to natural hues once again: “terracotta clay” paint for the kitchen walls and “sunbaked” carpets in the living and dining rooms.
Of course, I’m not the only one who routinely takes inspiration from nature. Following are nine environmental and health issues, all of which may soon be remedied by taking cues from the natural world.
1. Butterfly-inspired nanofilms to reduce cooling energy needs
On a hot summer day, you know that wearing white clothing will make you feel cooler than sporting other colors—such as black or blue—due to white’s ability to reflect rather than absorb sunlight.
A car with blue paint, for example, appears blue because it absorbs yellow light and reflects blue light. The large amount of light that is absorbed heats the car. Blue morpho butterflies, however, produce their highly saturated blue color based on the nanostructure of their wings. Now, researchers, publishing a report in the science journal Optica in August 2023, have designed a cooling nanofilm that mimics these structures, resulting in vibrant colors that don’t absorb light like traditional paint.
To test this new technology, researchers created blue, yellow and colorless films, which they placed outdoors on surfaces such as cars, cloth, cell phones and roofs from 9 a.m. to 4 p.m. in both summer and winter. Using infrared cameras and thermocouple sensors to measure temperature, the scientists showed that the films they developed lowered the temperature of colorful objects about 35 degrees Fahrenheit below the ambient temperature. They also discovered that when left outside all day, the blue-colored films were approximately 78 degrees Fahrenheit cooler than traditional blue car paint.
In buildings, large amounts of energy are used for cooling and ventilation; and running the air conditioner in electric cars can reduce the driving range by more than half. These butterfly-inspired cooling films—which no matter the desired brightness, color or saturation don’t absorb any light—could help advance energy sustainability and carbon neutrality; and they could be used on the outside of buildings, equipment and vehicles to reduce energy needs. They could even be used on textiles to create clothes of any color that are comfortable in hot temperatures.
2. Chameleon-inspired coatings for shifting energy needs
Many desert creatures have specialized adaptations to allow them to survive in harsh environments with large, daily temperature shifts. For example, the Namaqua chameleon of southwest Africa alters its color to regulate its body temperature as conditions change. The animals appear light grey in hot temperatures to reflect sunlight and keep cool, then turn dark brown once they cool down to absorb heat instead. This unique ability is a naturally occurring example of passive temperature control—a phenomenon that scientists believe could be adapted to create more energy-efficient buildings.
To make a color-shifting coating that would adapt as outside temperatures fluctuate, researchers mixed specialized microparticles, thermochromic microcapsules and binders to form a suspension, which they brushed or sprayed on a metal surface. When heated to 68 degrees Fahrenheit, the surface began to change from dark to light grey. Once it reached 86 degrees Fahrenheit, the light-colored film reflected up to 93% of solar radiation. Even when heated above 175 degrees Fahrenheit for an entire day, the material showed no signs of damage.
The new coating was then tested alongside three conventional coatings: regular white paint; a passive, radiative cooling paint; and blue steel tiles. All were placed on miniature, doghouse-sized buildings that were located outside throughout all four seasons. Results, published in the American Chemical Society’s Nano Letters journal in September 2023, showed that during spring and fall, the new coating was the only system that could adapt to widely fluctuating temperature changes, switching from cooling to heating throughout the day.
The researchers say that this color-changing system could save a considerable amount of energy—and fossil fuels—in regions that experience multiple seasons, while still being inexpensive and easy to manufacture.
3. Gecko-and-inchworm-inspired robots for rescue and surgical needs
A tiny robot that could one day help doctors perform surgeries and emergency-response teams conduct search and rescue operations was inspired by the incredible gripping ability of geckos and the efficient locomotion of inchworms.
The new robot, developed by engineers at the University of Waterloo in Ontario, Canada, utilizes ultraviolet light and magnetic force to move on any surface—even up walls and across ceilings. It’s the first soft robot (those composed of compliant materials versus rigid) of its kind that doesn’t require a connection to an external power supply, enabling remote operation and versatility for use in otherwise inaccessible places.
Constructed from a smart material, the robot—dubbed the GeiwBot because of the animals that inspired it—can be altered at the molecular level to mimic how geckos stick and unstick the powerful grippers on their feet. That enables the robot, which is about 1.5 inches long, 0.11 inches wide and 0.039 inches thick, to climb on a vertical wall and across the ceiling without being tethered to a power source.
The research team constructed the robot using liquid crystal elastomers and synthetic adhesive pads. A light-responsive polymer strip simulates the arching and stretching motion of an inchworm, while gecko-derived magnet pads at either end do the gripping.
An untethered soft robot paves the way for potential surgical applications via remote operation inside the human body and for sensing or searching in dangerous or hard-to-reach places during rescue operations. This work marks the first time that a soft robot has climbed on inverted surfaces.
To see how the robot moves, watch the short video, below.
4. Jellyfish-inspired robots for ocean cleanup needs
Most of the world is covered in oceans, which, unfortunately, are highly polluted. Seventy percent of marine litter is estimated to sink to the seabed; and plastics make up more than 60% of this litter, which will take hundreds of years to degrade.
One of the strategies to combat the mounds of waste found in these very sensitive ecosystems—especially around coral reefs—is to employ robots. However, existing underwater robots are typically bulky with rigid bodies, unable to explore and sample in complex and unstructured environments. They’re also noisy due to electrical motors or hydraulic pumps. For a more suitable design, scientists at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, looked to nature for inspiration. They configured a jellyfish-inspired, energy-efficient, versatile and nearly noise-free robot the size of a hand.
To build the robot, state the scientists in the journal Science Advances, they used electrohydraulic actuators through which electricity flowed. The actuators served as artificial muscles to power the robot. Air cushions surrounded these “muscles,” as well as soft and rigid components which stabilized the robot and made it waterproof so that the high voltage running through the actuators would not have contact with the water. A power supply periodically provided electricity through thin wires, causing the artificial muscles to contract and expand. This allowed the robot to swim gracefully and to create swirls underneath its body.
When a jellyfish swims upwards, it creates currents around its body so that it can trap objects along its path and collect nutrients. This robot, too, circulates the water around itself, useful in gathering things without physical contact, such as waste particles. It can then transport this litter to the surface, where it can later be recycled. Jellyfish-bots are also able to collect fragile biological samples, such as fish eggs. Meanwhile, there are no negative impacts on the surrounding environment; the interaction with aquatic species is gentle and nearly noise-free—much like its natural counterpart.
The new jellyfish-bots can operate either alone or in combination. They require only a small input of power and are safe for humans and fish should the polymer material insulating the robot somehow be torn apart.
5. Octopus-inspired controls for soft robot agility needs
Octopus arms coordinate almost infinite degrees of freedom to perform complex movements such as crawling, fetching, grasping, reaching and swimming. How these animals achieve such a wide range of activities remains a source of amazement, inspiration and mystery. But if unraveled, the intricate organization and biomechanics of the internal muscles of octopus arms could provide soft robots with even more agility.
So, researchers at the University of Illinois Urbana-Champaign endeavored to develop a physiologically accurate model of octopus arm muscles to create a framework for the design and control of next-generation soft robots.
Octopus arms are driven by three major internal muscle groups—longitudinal, oblique and transverse—that cause the arms to deform in several modes: bending, extending, shearing and twisting. This endows octopuses’ soft, muscular arms with significant freedom, unlike any rigid counterpart.
The university team’s key insight, which was explained in the journal Proceedings of the Royal Society A in February 2023, was to describe the arm musculature using a “stored energy function,” a concept borrowed from the theory of continuum mechanics. An octopus’s arm rests at the minimum of an energy landscape. Muscle actions modify the stored energy function, thus shifting the equilibrium position of the arm and guiding the motion.
Interpreting octopus muscles using stored energy dramatically simplifies the design of how their arms are controlled. In particular, the study outlines an energy-shaping control methodology to compute the necessary muscle activations for solving manipulation tasks such as reaching and grasping. This model led to remarkably lifelike motion when an octopus arm was simulated in three dimensions.
6. Spider-silk-inspired fibers for synthetic production needs
Scientists have often eyed spider silk as an enticingly sustainable alternative to synthetic fibers, which can release harmful microplastics into the environment and are often produced from fossil fuels that generate greenhouse gas emissions. Previously developed processes for spinning artificial spider silk, however, have failed in applying a surface layer of glycoproteins and lipids to the silk to help it withstand exposure to sunlight and humidity—the antiaging “skin layer” that spiders use on their webs.
Genetically modified silkworms offer a solution to this problem since silkworms coat their own fibers with a similar protective layer. And, luckily, silkworm silk is presently the only animal silk fiber commercialized on a large scale, with well-established rearing techniques. Consequently, employing genetically modified silkworms to produce spider silk fibers would enable a low-cost, large-scale commercialization.
To spin spider silk from silkworms, scientists in China introduced spider silk protein genes into the DNA of silkworms so that these genes would be expressed in the silkworms’ glands. The researchers also performed “localization” modifications on the transgenic spider silk proteins to ensure that the silkworms would spin the fibers properly.
The result was fibers that are six times tougher than the Kevlar used in bulletproof vests. Published September 20, 2023, in the science journal Matter, this study is the first to successfully produce full-length spider silk proteins using silkworms.
These findings demonstrate a technique that could be used to manufacture an environmentally-friendly alternative to synthetic, commercial fibers such as nylon. This type of fiber could be used as surgical sutures, addressing a global demand exceeding 300 million procedures annually. The spider silk fibers could also be used to create more comfortable garments and innovative types of bulletproof vests; and they may have applications in aerospace technology, biomedical engineering, the military and smart materials.
7. Beetle-and-spider-web-inspired harvesting methods for freshwater needs
Traditionally, freshwater for consumption is collected from groundwater, lakes, rivers and oceans (with treatment). Using nature as an inspiration, scientists are now learning how to harvest water from alternative sources as the world faces the serious challenge of freshwater scarcity.
A spider’s web is an engineering marvel that can efficiently capture water, say researchers at the University of Waterloo in Ontario, Canada. A spider doesn’t need to go to a river to drink, as it can trap moisture from the air. Similarly, Namib desert beetles have no easy access to water but acquire it from the air by leaning into the wind and reaping droplets from fog with their textured body armor, allowing the moisture to accumulate and drip into their mouths.
To mimic the beetles’ unique surface structure and the construction of spiders’ webs, Waterloo scientists are designing and fabricating similar surfaces using cellulose-stabilized wax emulsions—net-zero carbon materials—that will attract tiny water droplets while swiftly releasing larger ones.
The next step is to develop a scalable process to engineer such surfaces. In a recent publication in Nature Water, the scientists discuss several promising, new water collection and purification technologies.
8. Termite-inspired systems for climate-smart building needs
Termites create mounds that have sophisticated ventilation systems that enable air circulation throughout the structures. This helps to maintain and regulate temperature and humidity. Now, the climate control used by termites in their mounds could inspire tomorrow’s climate-smart buildings. New research from Lund University in Sweden shows that future buildings inspired by the termites could achieve the same effect as traditional climate control, but with greater energy efficiency and without its carbon dioxide footprint.
Traditional air-conditioning uses the bulk flow principle, normally driven by fans. By focusing on the interior of termite mounds—which consist of thousands of interconnected air chambers, channels and tunnels that capture wind energy to “breathe,” exchanging oxygen and carbon dioxide with the surroundings—it is possible to develop systems that are dynamic, turbulent and variable. In addition, they can be controlled by very small equipment, and they require minor energy provision.
In a study that was published in the journal Frontiers in Materials, the Lund University researchers demonstrated how the termite mound airflows interact with geometry, the parameters in the structure that cause the flows to arise and how they can be selectively regulated. These can be driven without using mechanical components such as fans or valves; requiring instead only electronic controls and the ability to create complex internal geometries (on the millimeter to centimeter scale) using 3D printing.
9. Baby-sea-turtle-inspired robots for sand locomotion needs
Robots that can move through sand face stronger forces than those designed to move through air or water. They also get damaged more easily. However, the potential benefits of solving locomotion through sand include the ability to conduct search and rescue missions, dig on the seafloor, inspect grain silos and measure for soil contaminants.
To better understand sand and how robots can travel through it, a team of roboticists at the University of California San Diego began experimenting. Sand is particularly challenging because of the difficulty sensing obstacles, the friction between sand grains that leads to large forces and the fact that it switches between behaving like a liquid and a solid depending on the context.
The UC San Diego team believed that observing animals would be the key to developing a robot that can swim in and dig itself out of sand. After considering worms, they landed on sea turtle hatchlings, which have enlarged front fins that allow them to surface after hatching. Turtle-like flippers can generate large propulsive forces, allow robots to steer and have the potential to detect obstacles.
After extensive simulations and testing, the researchers decided on a tapered body design and a shovel-shaped nose. Their resultant streamlined and strong robot can, indeed, swim under the sand at a depth of five inches and dig itself out, thanks to two front limbs that mimic the oversized flippers of turtle hatchlings. The robot can travel at a speed of 1.2 millimeters per second—roughly 13 feet per hour. While this may seem slow, it’s comparable to the speeds of other subterranean animals, such as clams and worms. Force sensors at the end of its limbs allow the robot to detect obstacles while in motion. It can operate untethered and be controlled via Wi-Fi.
To keep the robot at a level depth in the sand, the researchers designed two, foil-like surfaces, which they placed on the sides of the bot’s nose. The robot detects obstacles by monitoring changes in the torque generated by the movement of its flippers. Next steps include increasing speed and allowing the robot to burrow into the sand, in addition to digging itself out. The work was presented in the May 12, 2023, issue of Advanced Intelligent Systems.
Nature-inspired hues for home improvements
Nature has had millions of years to understand what works best on our planet and what doesn’t. Biomimicry aims to favor those “choices” tested by nature. I think it’s only smart to look to nature now to help solve our most pressing environmental and health-care challenges. Too, our turning to the natural world is a sign of respect, which we are long overdue in paying.
So, I’ll keep looking to nature for ways to improve my well-being—and even for what colors should cover my kitchen’s walls.
Here’s to finding your true places and natural habitats,