Scientist Susie Jahren demonstrates a self-healing liquid polymer coating. Photo: Werner Juvik.
Self-repair is one of the most promising functions of smart materials, and is now represented by a variety of material families including plastic and concrete. The capability to autonomically heal results in materials that can last longer without maintenance, and which demand fewer resources for structural applications.
Recently, SINTEF scientist Susie Jahren and her research team have created a self-repairing textile. Designed for professional fishermen whose attire takes a beating at sea, Jahren’s textile coating self-heals small tears that develop in the surface of waterproof clothing.
“We have shown that the principle works. Holes and tears we have made in test pieces in the lab close up all on their own,” Jahren says.
To create the coating, the scientists added micro-capsules of healing agent to liquid polyurethane. When the polyurethane hardens, it forms a resilient surface that bonds with the textile. Jahren explains that “if the coating tears, the capsules burst in the damaged area. Here the sealant content is released and hardens when it comes in contact with water and air, so the coating seals itself.”
Since traditional polyurethane poses health hazards, it would be ideal if Jahren’s team could use an isocyanate-free or bio-based polyurethane resin. For now, the project is still in the laboratory testing phase.
“In this project we are at the same time developing durable coatings intended to reduce the likelihood of holes and tears occurring at all,” Jahren says. “The garments we are developing for fishermen will also include integrated floatation functions. We also plan to incorporate a man-over-board button in the clothing which sets off an alarm enabling fishermen to be located rapidly in the event of an accident.”