Artificial muscles made from fishing line

Des fils de nylon ou de polyéthylène torsadés, qui se contractent lorsqu’ils sont chauffés, pourraient servir à fabriquer des muscles artificiels performants et peu coûteux.

Stranded nylon or polyethylene wire, which contracts when heated, could help manufacture inexpensive and powerful artificial muscles.

Prototypes of humanoid robots are generally fitted with systems inspired by the human body. For instance, artificial muscles are used to provide mobility. An international team led by Ray Baughman, from the Texas Institute of Nanotechnology, has just demonstrated that fishing line is an excellent substitute for mimicking the action of organic muscles.

Many materials were studied in order to develop artificial muscles: shape memory metals and polymers, carbon nanotube-based fibres, conductive polymers, and more. Unfortunately, they all had significant drawbacks: high costs, quick to wear-out and significant hysteresis – which is the tendency to keep the shape obtained after a deformation. R. Baughman and his team demonstrated that nylon strands or polyethylene wires had significant advantages in terms of costs, hysteresis and longevity, but also in terms of performance: they are more effective than mammalian muscles.

These artificial muscles are made from nylon fishing line which is twisted until it forms a kind of spring. When heat is applied to the spring, it contracts up to 50%, which is twice the 20% contraction found in natural muscles.
When immersed in hot water, just four of these artificial muscles can lift weights of up to 13.6 kilograms.
These new "muscles" could be used in robots, artificial limbs or portable exoskeletons which would be smaller and lighter than current models based on hydraulic motors and systems.

More information
http://www.electromaterials.edu.au/news/UOW166242.html