If you prick us do we not bleed? Researchers at the University of Illinois at Urbana-Champaign have made a polymer material that can heal itself repeatedly when it cracks, by bleeding new material. This Harry Potter-like attribute is possible thanks to an embedded vascular network in the plastic similar to that found in biological organisms. Using a modern variation of the 'lost wax casting process', the scientists were able to form micro channels throughout a substrate that are filled with a reactive 'healing fluid'. This fluid filled substrate is then wrapped with a brittle epoxy 'skin' that is doped with a catalyst. When the 'skin' is broken the 'healing fluid' fills the space and forms a seal, thus repairing the tear. Every 5 year old knows how a scab on her knee bleeds and then heals - the idea is simple. But creating a human designed proof of principle is a large step in materials science, and a striking example of learning from the biological process. The sustainability wins in the present technology are a bit of stretch. The cost of the process and the materials will keep this technology in the laboratory. The ability to create micro-channeled materials may lead to advances in counter current heat exchange systems (again similar to biological design). But the real next sustainable step is to learn how to create the materials with non-toxic, cheap, room temperature chemistry. At any rate, I imagine it will change my relationship with toys - if I step on a Lego will it bleed?
Photo Credit: J. Hanlon, Univ. of Illinois Beckman Institute
::MIT Technology Review ::Eureka Alert

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