Materials that self-heal

Edit Hook

“Researchers are developing self-healing membranes and foams. As soon as a membrane suffers damage, an additional layer provides “first aid”, thanks to its mechanical pre-tensioning, closing the hole until a proper repair can be made. This is analogous to the natural process which occurs in lianas. While researchers from the University of Freiburg under the direction of Olga Speck are busy studying the biological and chemical aspects of the model provided by liana plants, Rolf Luchsinger and Markus Rampf at Swiss Federal Laboratories for Materials Science and Technology’s (EMPA) Center for Synergetic Structures are working on technical solutions for polymer membranes. Luchsinger’s impetus, however, concerns neither inflatable boats nor air mat-tresses but rather load-carrying pneumatic structures for lightweight construction. His tensairity beams serve as elements for quickly erected, lightweight bridges and roofing.” (Source: Nature shows the way, news release from EMPA’s Center for Synergetic Structures, September 23, 2011,—/l=2

Biomimicry Story

The researchers have been studying self-healing in plants since the early 2000s. The self-healing foams and membranes are inspired by the way that the pipevine, Aristolochia macrophylla, self-heals. When the lignified cells of the outer supportive tissues which give the plant its bending stiffness are damaged, the plant administers repairs the wound. Parenchymal cells (thin-walled cells under the epidermis) from the underlying base tissue expand suddenly and close the lesion from inside. Only in a later phase does the real healing process kick in and the original tissue grows back.See: M. Rampf, O. Speck, T. Speck, R. Luchsinger. 2010. Self-repairing membranes for inflatable structures inspired by a rapid wound sealing process of climbing plants. Journal of Bionic Engineering. 8:242–250

Challenges Solved

Lightweight structures that are filled with air run the risk of losing their integrity if punctured. By incorporating the ability to temporarily or permanently self-repair, these materials will last longer and continue to provide support until they can be permanently repaired.

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