Looked at one way, carbon fiber composites are just our simplistic human analog of natural nano-featured composites like those that make up mussel and abalone shells. Mollusks use a “digital” process for creating their shells – a digital process controlled by a computer running DNA as its code. What if we could make composites like those little molluscs – stronger and more resilient than some random fibers jammed into some plastic?
Now researchers at the Swiss Federal Institute of Technology in Zurich, following on work done at Michigan and MIT, have created a new bio-inspired material that combines the strength of ceramics with the stretchiness of polymers. Consisting of ceramic platelets in a polymer matrix, like bricks in mortar, the material is both light and strong – approximately four times as strong as steel.
In designing the material, the researchers carefully studied the mechanical structure of nacre, the shiny layer on the inside of seashells, and tried to improve it. Nacre has platelets made of calcium carbonate arranged in layers inside a protein-based polymer. “There’s something very special about the size of these platelets,” Studart says. “Nacre uses specific platelet length and thickness to achieve the high strength and [stretchability] that you see in metals.”
This type of biomimicry is the next major frontier of materials science. Sea shell, or nacre, has long been a target for researchers in the emerging field of biomimetics – literally “copying life” – along with artificial photosynthesis for gathering sunlight as energy, multiple other materials such as spider silk, and a whole host of behaviors and capabilities that the natural world has evolved over hundreds of millions, or even billions, of years.
The combination of nature’s techniques, such as creating nacre with a digital process, and Man’s inventiveness is ushering an era of materials with amazing properties – just in time to address some of the most significant problems we’re facing, including global climate change and sustainable energy.