Starting at the scale of material science with new textiles, coatings and paints, the examples of biomimetic product design include improved medical tools, fans, propulsion mechanisms, vehicles, trains, boats, planes, renewable energy systems, smart meters, desalination technologies, carpets, windows and packaging systems; to name just a few of the breathtaking varieties of biologically inspired products on the market today. Let us explore a few of these innovations.
What can butterflies teach us about colours without pigments and dye? Butterflies in the genus Morpho can be recognized by their iridescent blue-toned colour which is not based on pigments but on how the surface structure of their wings diffracts and scatters light. The diverse species in this genus deploy colour to attract attention. Donna Sgro, an Australian fashion designer has created three dresses from a fabric called Morphotex, a pigment-free and dye-free textile developed by Tejin Fibres Limited in Japan. This iridescent blue material draws its colour from optical interference (Vanderbilt, 2012) based on the way fibres of different thickness and structure are inter-woven (Ask Nature, 2015a).
There are many examples of how nature has evolved functional surfaces based on their structure at the nano-scale. The micro-topography of the lotus leaf makes it extremely hydrophobic and therefore water repellent. This creates self-cleaning properties resulting in dirt-free surfaces. The leaf of the lotus (Nelumbo nucifera) forces water into droplets rather than letting it stick to it. These droplets then roll off, collecting dirt particles in the process (Ask Nature, 2015b). In 1982 Wilhelm Barthlott applied this biomimetic insight to the creation of a self-cleaning paint which is sold under the brand name Lotusan and is now used on hundreds of thousands of buildings.
What can we learn from sharkskin in the design of functional surfaces? Sharks are the fastest swimming marine organisms. This is due not only to their effective streamlined shapes, but also to their special skin that is covered in small teeth (dermal denticles) instead of scales. These denticles are aligned to produce vortices, spiral-shaped eddies that flow along the body of the shark, reducing friction (drag) as the animal glides through the water. Innovators at Speedo Aqualab applied this principle to the design of a revolutionary new swim suit which caused a stir at the 2000 Olympics when 80% of the medals were won by swimmers wearing this shark-skin inspired material. The Fastskin suits gave swimmers the advantage of a 3% increase in swimming speed (Waller, 2012). The suit has since been banned for competitions.
California-based Sharklet Technologies, has create a thin-film covered in microscopic diamond-shaped plates, which mimic the surface structure of shark-skin and effectively stop potentially dangerous microorganisms from establishing themselves on surfaces covered with this film. This method does not attack or kill the bacteria, but simply makes it so difficult to stay attached to these surfaces that they cannot form colonies and spread. As a result, this approach — unlike the use of antibiotics — will not create resistant microbes (Cooper, 2009). This is important as the spread of so called ‘super-bugs’ like MRSA and other potentially fatal strains of Staphylococcus and Escherichia coli is one of the growing concerns of the World Health Organization. Sharklet Technologies is collaborating with the US Navy to create an alternative to copper-based paints now in use as marine anti- fouling agents (Sharklet Technologies, 2015). Replacing such paints would not only drastically reduce a major source of marine pollution, but also keep ships’ hulls free of attached barnacles and algae which reduce their fuel consumption by preventing drag.
Biomimetic design can be inspired by biological materials and by the surface structures and body shape or form of certain species. In 2004, a team of engineers at the Mercedes-Benz Technology Centre and at Daimler Chrysler Research decided to develop a bionic concept vehicle, looking for ways to optimize the mono-volume approach with aerodynamic performance and strength. The biological model from which they drew their design inspiration and lessons was the boxfish (Ostracion cubicus). Surprisingly the cube-shaped body of this tropical fish is extremely streamlined. Models of the fish tested in a wind-tunnel achieved wind drag coefficients of just 0.06, an aerodynamic ideal. The resulting full-scale concept car was among the most aerodynamic vehicles in this size category ever developed. According to Daimler, fuel consumption was reduced by 20%.
In addition to taking inspiration from the boxfish’s aerodynamic shape, the team also studied the strength-to-weight ratio of the skeletal structure of the fish that gives it optimal strength with minimal material (weight) use. Again according to Daimler, transferring the optimized skeletal design of the boxfish to the concept car allowed the engineers to increase the rigidity of the external door panelling by 40% compared to conventional designs and led to a reduction of one third in the overall weight without diminishing strength or crash safety (Daimler Chrysler AG, 2004).
Can whales teach us to build more effective windmills? The inventor Frank Fish studied the humps on the front edge of the fins of humpback whales (Megaptera novaeangliae). He discovered that these so-called tubercles compress the fluid flowing past the fins, giving the whales extra lift and propulsion to engage in their breathtaking ‘breaching’ when these animals (weighing up to 36 tonnes) propel themselves out of the water.
The Whalepower Corporation is now applying this insight to the design of new fans with improved efficiency and wind-generator blades that increase the power output at a given wind regime. The technology can also be retrofitted on existing turbine blades. The application of this tubercle technology to the aircraft industry might result in more efficient planes with more lift. Maybe humpback whales will inspire the next step in aircraft efficiency?
There are already many biomimetic designs in the airline industry. Swans inspired the Concorde’s distinctive nose, for example, and the up-turned wing tips now common on most aeroplanes are turbulence-reducing measures inspired by birds of prey.
One of the most famous examples of biomimicry-based innovation is the Shinkansen 500- series bullet train that was made faster, more energy efficient, and quieter by using design principles copied from the beak of a Kingfisher (Alcedo atthis) (Ask Nature, 2015c). Many fast and efficient train designs have since been based on the aerodynamic shapes of other birds like the Spanish AVE 102 series with a locomotive that was shaped like a duck’s bill.
Learning from natural processes does not have to be limited to mimicking specific species, but can also be based on the general patterns and processes we can observe in nature. Jay Harman spent time as a designer of boats. His love for the ocean and obsession with the way water flows inspired him to study the ‘streamlining principle’ behind the formation of whirlpools.
Learning from the geometries formed by flowing and whirling water, Harman created PAX Scientific to bring the exceptional efficiencies of natural flow to fluid-handling technology like mixers, pumps, turbines, heat exchangers, ducts and propellers. One of the company’s products, the Lilly Impeller, is a highly efficient water-mixing device based on these principles. Other examples include more efficient fans for cooling applications, ship propulsion systems and a new kind of desalination system.
The list of biologically inspired product design innovations is almost inexhaustible. These examples simply illustrate the diversity of applications of biomimicry at the product scale. There are many more.
[This is an excerpt of a subchapter from Designing Regenerative Cultures,published by Triarchy Press, 2016.]