Inspired by nature
Bioengineer Dr Peter Gray, from technology company 3M, explains how nature inspires new products.
Biomimicry or biomimetics (from bios, meaning life, and mimesis, meaning to imitate) is a new discipline that studies nature, its models, systems, processes and elements. It then imitates these designs and processes to solve human problems by inspiring products with improved design and performance.
Nature’s process of natural selection has over the last 3.6 billion years helped to refine the living organisms, processes and materials on planet Earth. Biomimetics has led to new technologies based on ‘biologically inspired’ optimised designs.
A famous example
Arguably the most famous example of biomimicry was the invention of Velcro™ brand fasteners by Swiss engineer George de Mestral in the 1950s. His concept was based on an observation that certain weed seeds stuck tenaciously to his clothes and dog's fur. Under the microscope, he saw that the seeds had hooked spines that could catch on anything with a loop, such as clothing or fur. The spines provided the plant with a built-in seed dispersal system.
De Mestral had the idea of using the hook and loop principle to design a new system for temporarily joining two surfaces. At first, people thought his idea was stupid, but he managed to get interest from one fabric weaver who made two cotton strips that worked for a short time. De Mestral eventually found after trial and error that nylon was a material that could , with the right processing, be formed into perfect hooks. However, mechanising the hook-weaving process took eight years, and in total it was ten years before he established a mechanised process that worked. He finally patented the process in 1955.
Inspired by shark skin
Another famous (and controversial) example was the design of a new swimsuit material inspired by shark skin. Under an electron microscope, shark skin is found to comprise many overlapping scales, called dermal denticles, that have grooves along their length parallel to the direction of the water flow as the shark moves through the water. These enable water to pass over the shark more smoothly by disrupting the formation of small eddies on the skin surface that would otherwise create ‘drag’. Clever scientists then replicated the concept of ‘dermal denticles’ into high-technology swimwear fabrics. The fabrics increase the swimmer's glide through the water and reduce the absorption of water by the suit. In fact the application was so successful that the swimsuits received a lot of publicity during the 2008 Summer Olympics and the sport’s governing body eventually banned the materials because of their effect on swim times.
My company, 3M, has also used these features of shark skin to create drag-reduction riblets. Again, these take advantage of the reduced drag associated with the directional dermal denticles. Drag-reduction riblet films have been employed to reduce drag on wind turbine blades, Formula 1 racing cars, aeroplane wings and fuselages and even on the hulls of racing yachts.
The same principle has been applied to a type of line used in fly fishing. Called the Scientific Anglers Sharkskin Series of fly fishing lines, they allow fly fishers to cast further with less effort and with less line tangling. Rather than being smooth like other fishing lines, Sharkskin has a micro-textured surface to reduce drag and so improve accuracy when casting.
To the future
I could give many other examples from 3M’s research and development program: multilayer optical films used in LCDs and inspired by the micro-structure of a butterfly’s wing; new self-sharpening abrasives that replicate the pattern of sharks’ teeth; lightweight insulation materials inspired by animal fur; and many more.
Bio-inspired research is experiencing significant growth, and discoveries in biomimetics have driven some important areas of current research. Current literature cites a rapid rate of growth in publications related to biomimetics, with the number of publications growing exponentially, doubling almost every 2–3 years since the 1990s and covering a broad range of fields.
The most popular areas include robotics and control, particularly robotics based on patterns of animal behavior; biomaterials science; and structural bioengineering. Other growing areas include the design of future buildings and cities, architectural design, farming systems and green materials (chemicals derived from renewable sources instead of fossils fuels).
So it seems that as long as there continue to be new discoveries in the natural world, there will be new models, systems, processes and materials that inspire people to design new products that imitate the best features of those natural systems.
Dr Peter Gray is Technical Manager for technology company 3M Australia, a key sponsor of the Australian Museum Science Festival.
An edited verison of this appeared in Explore 35(2), spring edition 2013.
Brendan Atkins , Publications Coordinator