Based on the "liquid wire" technique in spider webs, a team of international researchers has created composite fibers which extend like a solid and compress like a liquid, according to a study recently published by the University of Oxford.
Pulling on a sticky thread in a garden spider's orb web and letting it snap back reveals that the thread never sags but always stays taut, even when stretched to many times its original length.
This is because any loose thread is immediately spooled inside the tiny droplets of watery glue that coat and surround the core gossamer fibers of the web's capture spiral, according to the study, which was carried out by researchers from the University of Oxford and the Pierre and Marie Curie University, Paris.
"Surprisingly, each drop packs enough punch in its watery skins to reel in loose bits of thread. And this winching behavior is used to excellent effect to keep the threads tight at all times, as we can all observe and test in the webs in our gardens," said Prof. Fritz Vollrath form the University of Oxford.
The novel properties observed and analyzed by the researchers rely on a subtle balance between fiber elasticity and droplet surface tension. The team was also able to recreate this technique in the laboratory using oil droplets on a plastic filament.
This artificial system behaved just like the spider's natural winch silk, with spools of filament reeling and unreeling inside the oil droplets as the thread extended and contracted, according to the study.
"Our bio-inspired hybrid threads could be manufactured from virtually any components. These new insights could lead to a wide range of applications, such as micro-fabrication of complex structures, reversible micro-motors, or self-tensioned stretchable systems," said Herve Elettro, the first author of the study and a doctoral researcher from the Pierre and Marie Curie University.
The study has been published in the journal Proceedings of the National Academy of Sciences.
