NANOSCIENCE... Everyone knows ceramics are brittle and break easily. So imagine putting one in a vise and squashing it to less than half its former size – and then having it pop back to its original shape. That is exactly what Julia Greer has done with a nanoscale ceramic lattice. Although it is more than 99.9 percent air, it is very strong and surprisingly flexible. Greer, a board member of Caltech’s Kavli Nanoscience Institute, is interested in creating structures, like lattices, that give materials unusual combinations of properties. If she can scale them up, she might be able to build floating ceramic balloons that replace helium with an even lighter vacuum, yet would not collapse inwards when pumping out air like a conventional balloon or inflatable toy. Her crushable ceramics are another example. Ceramics consist of tiny ceramic grains bonded to one another, and also flaws like air bubbles and chunks of non-ceramic materials. Hit or bend a ceramic and cracks will form at those flaws and rapidly break the ceramic apart. Greer’s team figured that if it could build its lattice from ceramic tubes with walls less than 10 nanometers thick, the flaws would be too small and too few in number to initiate cracks. So instead of breaking apart, the ceramic would buckle and spring back to its original shape.
Posted on: Tue, 16 Sep 2014 17:28:29 +0000