The first self-healing material was reported by the UIUC [University of Illinois at Urbana-Champaign] researchers six years ago, and other research groups have created different versions of such materials since then, including polymers that mend themselves repeatedly when subject to heat or pressure. But this is the first time anyone has made a material that can repair itself multiple times without any external intervention, says Nancy Sottos, materials-science and engineering professor at UIUC and one of the researchers who led the work.
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the researchers bend it and crack the polymer coating. The crack spreads down through the coating and reaches the underlying microchannel. This prompts the healing agent to “whip through the channels and into the crack,” Sottos says. There, it comes into contact with the catalyst and, in about 10 hours, becomes a polymer and fills in the crack. The system does not need any external pressure to push the healing agent into the crack. Instead, the liquid moves through the narrow channels just as water moves up a straw.