Scientists at KIT (Karlsruhe Institute of Technology) in Germany have created a lightweight but very strong material inspired by the intricate microscopic architecture of living tissue – our own bones. The research could pave the way for future super-light materials that could be used in microfluidics devices or to make lighter (and thus cheaper) spacecraft.
Industrial materials like steel are often solid and thus very dense and heavy – which is a drawback if you’re trying to make something strong but light (like a plane). Even though experts have managed to make artificial ‘cellular’ materials like aluminum foam, which is full of air pockets and thus much lighter than a solid hunk of metal, there’s a trade-off – the porous metal is much weaker than solid metal would be. It’s not easy to engineer strong materials less dense than water (which is about 1,000 kilograms per cubic meter).
Wood and bone don’t seem to have this problem. These living tissues, natural cellular materials, are porous but still very strong – and it’s because of how the air pockets are arranged. In metal foam, the air bubbles are random, and so is the structure. But in wood and bone, there’s a complex architectural pattern to the bits of bone crisscrossing through all those air pockets that are designed to bear loads.
Wood and bone have another advantage. Their cellular architecture starts on very tiny, microscopic scales, which allows them to take advantage of the size effect—the smaller your building material, the stronger it gets.
So the researchers used a 3D laser lithography machine – basically a very fancy 3D printer – to build very tiny microstructures out of a ceramic-polymer composite. They made several different designs, from cubic grids with diagonal supports to hexagonal honeycomb-like structures.
These light building materials were remarkably tough – they exceeded the strength to weight ratio of all engineering materials with a density less than that of water, the researchers said.
Source: latimes.comAdded: 24 February 2014