Protective Textiles: Inspired By Nature

Earth is incredibly diverse, with an estimated 8.7 million plant, animal, and fungal species.1Evolution has produced single-celled organisms and megafauna weighing hundreds of tonnes, and each of these species has been precisely adapted to its environment. No one species is capable of dealing with everything the planet can hurl at it, but over centuries of natural selection, these organisms have evolved some remarkable self-protection mechanisms.

Humans have replicated these adaptations for thousands of years, and the textile and fabric industries are no exception. Seneca the Younger, an ancient Roman philosopher, once claimed that all art is a copy of nature. Even the most basic felted textiles draw inspiration from the fur of the animals from which they are created. When it comes to biomimicry in textiles, there is a whole world to explore. Velcro and other hook-and-loop fasteners, for example, were famously inspired by burrs that became trapped on George de Mestral’s trousers while hiking. However, these improvements did not end with the 1940s. Here are some of the most recent advances in protective textiles that are inspired by nature.

Tensile Strength: Inspired by Spiders

Spider silk is one of the world’s strongest natural fibres, so it’s no wonder that humans have used it to produce fabrics with incredible tensile strength. The shape of spider webs may have inspired the design of the first fishing nets. Now that scientists can analyze it at the molecular level, they know exactly what gives spider silk its power and may draw inspiration from it. The proteins that make up spider silk are known as spidroins, and materials scientists have created various synthetic copies of them.

One of these artificial fibers, inspired by the silk of the Darwin bark spider, is made of a gelatinous substance (like actual spider silk) and has a tensile strength of 630 MPa and a hardness of 130 MJ/m.2This artificial polymeric fibre will have numerous applications in both heavy industry and medicine.

These materials are not just known for their strength and toughness. Real and artificial spider silk have a variety of interesting qualities, including supercontraction and strong thermal conductivity, making them ideal for making protective textiles. This allows these biologically inspired textiles to be employed as muscle and ligament substitutes, heat sinks, parachutes, and even bulletproof vests.

Durability and Cut Protection: Inspired by Fish, Crocodiles, Alligators, Geckos and Mushrooms

Many types of fish have hard scales that protect them from the elements and parasites. These are undeniably stunning, and many designers have drawn aesthetic inspiration from fish scales. However, a team of materials scientists in Canada has been motivated in a totally different way. At McGill University in Montreal, a study group led by Francois Barthelat examined over hundreds of fish species before choosing on the alligator gar, a freshwater fish native to North America. Barthelat’s team discovered that the alligator gar scales overlapped excellently for their objectives.

Furthermore, fish scales are the strongest collagen material known to humanity. Over several years, the researchers created a protective fabric with a nanoscale ceramic coating to make 3D printed armour gloves that can withstand cuts and piercings.

Fish are not the only animals with natural armour. Alligators and crocodiles have extremely strong skin that allows them to defend themselves against their prey and other predators. It’s no surprise that crocodile and alligator leather is highly valued in luxury clothes, such as shoes and belts. In 2023, a Chinese research team stated that it had created a new cloth inspired by the strength of crocodile skin. This soft-rigid unified structure combines a soft textile substrate with rigid blocks and epoxy resin, producing a textile that is resistant to abrasion, cuts, and punctures.

Meanwhile, a 2021 study published in the Autex Research Journal approaches biomimetics in cut-resistant fabrics from a different perspective. The majority of cut-resistant fabrics on the market are made with p-aramid yarns or core-spun around stainless steel. This causes a difficulty with grip strength, necessitating further coating with rubber or another non-slip material. Instead, this study applied a polymeric paste on four different types of materials, examining different forms of coating with each material, and discovered that biomimetic grip dots loosely modeled after gecko toes provided the optimal mix of comfort and grip strength.

Increasing fabric durability is critical to circularising the textile economy. One of the most significant tasks here is to reduce waste. The intrinsic strength of the tissue that makes up mushrooms’ root systems (also known as mycelium) has made fungi an excellent source of inspiration, and many designers, including Stella McCartney, have turned to mushroom leather as a vegan, sustainable alternative to real and synthetic leather. Even better, the mycelium can be coated with chitin (inspired by crab shells) for increased endurance. People have experimented with making children’s shoes out of mushroom leather. Children require robust footwear, and mycelium enables these shoes to be tough, thick, and fully biodegradable.

Waterproofing and Weather Protection: Inspired by Trees, Lotus Flowers, Ducks and Pinecones

Water may be one of the necessities of existence, but getting it into places it shouldn’t be can be disastrous. Humans have been making waterproof cloth for thousands of years, with indigenous South Americans using natural rubber latex in their garments. However, rubber stiffens in the cold and becomes sticky in hot temperatures, and it is not highly breathable, making it unsuitable for many clothes. In recent years, scientists have continued to draw inspiration from nature to develop new types of textiles that resist or evaporate water in seconds.

Nanotechnology brings up a plethora of new possibilities for developing water-resistant textiles. People have long recognized the water repellent properties of the carnauba palm tree (a native of Brazil). The carnauba leaves create a natural waxy material that has been used in a wide variety of applications. In 2020, a study team released data in The Journal of the Textile Institute about how they used chitosan to develop a water repellent nano-coating inspired by carnauba palms. This coating is effective on nylon, cotton, and nylon/cotton blends, and it retains hydrophobicity for more than thirty seconds after exposure to water.

Furthermore, it remains after being washed and is completely air permeable. Even better, the chitosan gave the treated fabrics antibacterial properties against E. coli and S. aureus.

Aquatic plants must be able to survive under water, hence many of them are hydrophobic. One example is the lotus, which has leaves with a microscopically rough texture that traps tiny air bubbles, making them superhydrophobic and allowing the flower to float on the surface. That is why, for at least a decade, textile experts have been inspired by the lotus leaf to create minuscule silver nanoparticles in cotton fabric. The resulting textile is not only hydrophobic, but it also resists ultraviolet radiation damage and prevents bacterial growth due to its high silver content.

Another interesting recent innovation in the realm of water-resistant fabrics has enormous potential not only for waterproofing, but also for oil and water separation. Inspired by the hydrophobic coating on duck feathers, this coating combines nano-titanium nitride (TiN), hydroxyl-terminated polydimethylsiloxane (HPDMS), and tetraethyl orthosilicate (TEOS) in a one-pot method. The nanocoating is abrasion resistant, and exposure to light restores its superhydrophobicity. This cotton-based material is 98% successful at separating oil from water and retains this ability over numerous applications, indicating tremendous promise for usage in cleaning oil spills and filtering oil at refineries.

Meanwhile, several pine tree species produce pinecones with seeds that open and close dynamically in response to environmental moisture and temperature. Lodgepole pine cones, for example, only release their seeds after being exposed to fire, allowing the new trees to develop freely. In 2020, scientists in the United Kingdom created fabrics inspired by pinecones’ inherent temperature fluctuations. One of their prototypes improves its permeability to airflow in damp situations while decreasing it by up to 30% in dry ones, which is the opposite of what many smart textiles do.4Their other prototype is a fiber that shrinks by 40% in damp environments and adjusts to changing humidity through hygronastic movement.

Ultraviolet and Sun Protection: Inspired by Full Sun Plants

The sun may be what makes life on Earth work, but for centuries, people have needed to protect themselves from its ultraviolet radiation. Many animals have fur, scales or feathers that serve this purpose, but humans do not. Sunburns can be incredibly painful and dramatically increase a person’s risk of developing skin cancer, so innovations in UV protective textiles have long been a priority in the industry. Traditionally, these fabrics are tightly woven to prevent ultraviolet infiltration or coated in chemicals that absorb or reflect the radiation. However, these chemicals tend to wash away or break down after two or three years of use, and the specialty weave that helps clothing block ultraviolet light makes a thick, non-breathable fabric. This is far from ideal for people who spend a lot of time in the sun.

Meanwhile, the entire plant kingdom requires this same ultraviolet radiation for survival. Some plants, such as tea and coffee, generally require at least twelve hours of sunlight per day as they grow. Chemists have examined this phenomenon and found that many of the compounds that help these plants make great use of sunlight also help absorb ultraviolet radiation, providing effective protection to the fabrics it is applied to and the person who wears them. The phenols in green and black tea extracts provide one of these forms of protection. Likewise, Betel leaf, prickly chaff flower and camel thorn bush produce copious amounts of UV-absorbent enzymes. These are easier to come across in many places, and they are far kinder to the environment than a titanium dioxide coating is.

Heat, Flame and Cold Resistance: Inspired by Polar Bears and Saharan Silver Ants

Firefighters are among the most important users of protective textiles. Their turnout gear needs to be extremely flame resistant, yet lightweight and easy to put on. For this reason, they are always on the lookout for new materials. Thankfully, the industry has come a long way from using asbestos fibres for this purpose. There are a number of protective textiles on the horizon inspired by naturally fire-resistant plants like the ponderosa pine and even certain cultivars of cotton. A United States Department of Agriculture (USDA) team based in New Orleans recently made a breakthrough in this regard. Last year, they were able to interbreed two lines of genetically engineered cotton, providing superior fire protection to either of the parent cultivars. This also allows them to avoid using harsh chemicals. This development will improve protective gear for firefighters, and it can also create soft, fully organic sleepwear for children in countries that require such clothing to be flame-retardant. This also negates the need to infuse such fabrics with formaldehyde.

One of the most surprisingly heat resistant animals on the planet is the Saharan silver ant, which lives in northern Africa and is routinely active in temperatures above 47C (a temperature that kills most other insects in seconds). The ants manage this through passive radiative cooling thanks to the silver triangular hairs that grow across their bodies. The hairs dissipate the heat from solar radiation and reflect near-infrared radiation, in large part due to the minuscule air gaps created by the hairs (often just a few hundred nanometres thick). There have been several studies on coating textiles with zinc oxide micro-crystal-bar composite to mimic this effect. These coatings have more than 95 per cent reflectivity, which can reduce a textile’s surface temperature by up to 17.7 per cent.5 In addition to its utility in textiles, this coating is now commonly used on solar panels, enabling the panels to be made larger without overheating.

Antarctica and the high Arctic may be frigid, but they are far from desolate. At both poles, plants and animals have evolved to deal with the cold temperatures and extended darkness. One of the most iconic Arctic animals is the polar bear. Polar bears have black skin and hollow, translucent fur that enables them to stay warm even in temperatures as low as -45o C. Earlier this year, a research team at the University of Massachusetts Amherst took its inspiration from the world’s largest bear to create an innovative textile that is far more thermally efficient than cotton while being thirty per cent lighter. It is made from nylon coated with a material they call PEDOT. As long as the wearer has access to light (either sunlight or artificial lighting), they can maintain their personal climate at colder temperatures without needing to use energy on extra heating. Smart textile producer Soliyarn has already begun to create cloth with this new material.

One of the most common utilities of textiles when it comes to temperature resistance is in insulation. Since most of the world has abandoned the concept of using asbestos fibres, modern home insulation is generally made from fibreglass, mineral wool and cellulose. Polar bear fur has been a great inspiration on this front as well, as its thermal properties are effective against both extreme cold and extreme heat. In 2021, one group developed a polymer nanofibre based on polar bear fur. It is designed for selective reflectivity, focusing on infrared radiation. This allows it to provide enhanced passive radiative cooling in the summer and keep heat indoors more effectively in the winter. As climate change continues to worsen, these developments are becoming increasingly necessary (and they can greatly reduce humanity’s reliance on climate control as well).

Luminescence, Colour, Camouflage and Increased Visibility: Inspired by Fireflies, Butterflies, Beetles, Birds and Cephalopods

A commonly neglected aspect in the field of protected textiles is the fabrics that prevent major injuries due to human Construction and airline workers commonly wear high-visibility reflective jackets at work, and people who spend significant time on roads at night can greatly benefit from this protection as well.

Fireflies that give light to summer nights and anglerfish that lure small animals to their lairs have something in common. Bioluminescence has long fascinated humans, and it has inspired some textile scientists to create fabrics with the principle in mind. In 2020, Dr. Sweta Iyer at the University of Boras published her doctoral thesis on the concept of using bioluminescence in textiles. This would be far more resource efficient than many current high-visibility textiles, and it may not require a power source for many uses. And thanks to this clever design, the light does not also generate heat.

Many animals that appear brightly coloured have little or no pigment. Blue morpho butterflies, tiger beetles and blue jays are strong examples of this principle. Although each species appears brightly coloured to the human eye, a microscopic view reveals that the colour comes from the microscopic scales on their wings or feathers. These scales are fine enough to reflect only certain wavelengths of light, giving them an iridescent appearance. A company called Amphico has taken advantage of this same principle to make textiles that are highly visible and brightly coloured while using up to 80 per cent less water and far fewer dyes than other methods.6 These materials are even biodegradable, further reducing their environmental footprint.

Camouflage is an incredibly common element in plants and animals alike, and the concept has long been a critical element of military and hunting textiles. For centuries, people have been integrating the colours and textures of their environment into textiles, but innovations in nanotechnology have allowed materials scientists to take inspiration from nature on the microscopic level. Soft-bodied cephalopods such as cuttlefish and squid are famous for their ability to change colour in a fraction of a second. A group of scientists at Harvard University have used this concept to create a soft, textile-based machine that utilises networks of microfluids to actively change its colour. This allows the machine to precisely match its environment, not only for visible light but for infrared radiation. The technology has not yet been adapted for garments, but it shows great promise for field shelters and other similar items.

Artificial Textiles: Natural Inspiration

Whether these materials take their inspiration from materials, construction or chemistry, the textile industry owes a great debt to the natural world. As with many topics, biology is a fractal concept: the deeper a person delves into it, the more they discover its vastness and complexity. There is a saying that “everything old is new again”, and species of plants, animals and fungi that came into existence millions of years before humans did are perhaps the best example of the principle.

Planet Earth holds millions and millions of wonders, and humanity stands to learn from every one of these. Many of the things that people call innovative have already existed for millennia; it is only humanity’s knowledge of the concepts that is new. Just as the mould that forms penicillin had existed long before Doctor Alexander Fleming discovered its utility, spider silk, polar bear fur and butterfly wings have been around at least as long as people have. The more deeply humanity connects with the natural world, the greater our ability to take advantage of these principles. Imagine what materials scientists will be able to do with fifty or one hundred further years of technological advancements. In the end, the best way for humanity to move forward is to connect with its natural roots.

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