A hole in an inflatable boat is only a disaster if the air escapes too quickly to reach the safety of land. It's somewhat less dramatic but nonetheless uncomfortable to spend the night on a leaky air mattress. Even in this case, though, you can get some uninterrupted sleep if only the air leaks out slowly enough. In future, self-repairing layers of porous material should ensure that the membranes of inflatable objects are not only water and airtight but also that they can plug up any holes on their own, at least temporarily.
The idea behind this comes from nature. Bionics experts keep on discovering amazing principles of construction which engineers can adopt for countless technical solutions. This is also the case with self-repairing materials. The self-healing process of the pipevine (Aristolochia macrophylla), a liana which grows in the mountain forests of North America, gave the biologists at the University of Freiburg, Germany, a decisive clue. When the lignified cells of the outer supportive tissues which give the plant its bending stiffness are damaged, the plant administers first aid to the wound. Parenchymal cells 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.
Self-healing inflatable structures
This principle is now being transferred to materials more specifically, to membranes in a bionics project sponsored by the German Federal Ministry of Education and Research. 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 an
|Contact: Dr. Rolf Luchsinger|
Swiss Federal Laboratories for Materials Science and Technology (EMPA)