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J4 ›› 2011, Vol. 8 ›› Issue (3): 242-250.

• article • Previous Articles     Next Articles

Self-Repairing Membranes for Inflatable Structures Inspired by a Rapid Wound Sealing Process of Climbing Plants

Markus Rampf1,2, Olga Speck2, Thomas Speck2, Rolf H. Luchsinger1   

  1. 1. Empa, Swiss Federal Laboratories for Material Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
    2. Plant Biomechanics Group, Faculty of Biology, Botanic Garden, University of Freiburg,
    Schänzlestraße 1, 79104 Freiburg, Germany
  • Online:2011-09-30
  • Contact: Rolf H. Luchsinger E-mail:rolf.luchsinger@empa.ch

Abstract:

A new self-repairing membrane for inflatable light weight structures such as rubber boats or Tensairity® constructions is presented. Inspired by rapid self-sealing processes in plants, a thin soft cellular polyurethane foam coating is applied on the inside of a fabric substrate, which closes the fissure if the membrane is punctured with a spike. Experimental tests are carried out with a purpose built setup by measuring the air mass flow through a leak in a damaged membrane sample. It is shown that the weight per unit area of the self-repairing foam as well as the curing of the two component PU-foam under an overpressure influence the repair efficiency. Curing the foam under overpressure affects the relative density as well as the microstructure of the foam coatings. Maximal median repair efficiencies of 0.999 have been obtained with 0.16 g·cm−2 foam cured at 1 bar overpressure. These results suggest that the bio-inspired technique has the potential to extend the functional integrity of injured inflatable structures dramatically.

Key words: self-repair, self-healing, biomimetics, inflatable structures, puncture resistance, PU foam coating