Gelatine and knitting patterns
One of the researchers’ main tasks is to make their material stronger. Silicone itself is too fragile, which is why the researchers want to make muscle fibres where the synthetic silicone is combined with natural proteins.
“By adding proteins that, for example, twist around the silicone elastomer, the artificial muscles mimic an original muscle structure even more, and this is important for strength,” says Anne Ladegaard Skov.
Originally, the idea was that the added proteins would come from spider silk, but as the wait for the material was long, the researchers started experimenting with other materials. So why not gelatin, they asked themselves. And it was a good question, because gelatin turned out to be surprisingly effective.
“We found that we could make the gelatin behave differently depending on how we heat treat it. Now we actually expect to soon be able to 3D print muscle fibres with gelatin in them,” says Anne Ladegaard Skov, who calls the discovery a fortunate coincidence. Especially considering that gelatin is virtually cost free. What can be a costly and long affair, however, is the development of the product design that will ultimately find its way into the consumers’ wardrobes.
“Whether you weave or knit, what patterns you use, and what fabric you combine the muscle structures with—it all impacts how effective the artificial muscles become,” explains Anne Ladegaard Skov.
So books on weaving and knitting patterns have found their way onto her bookshelf, and together with the rest of her research group, combination patterns and sewing constructions are closely studied in the search for the optimal product design.
“Just like inside the body, the way muscle structures are bundled impacts how they move. We try to incorporate this knowledge into our solution design. It’s important to give the artificial muscles optimal freedom of movement,” explains Anne Ladegaard Skov.