Sciences Participating with Arts & Culture in Education

Fishing Line, Supermaterial

Illustrated by Christophe Pichette

Ever dreamed of becoming a super hero? Of building a suit like Iron Man's? Using scientific enhancements like Captain America's or Wolverine's?

For years, biologists and engineers alike have been trying to replicate and even enhance muscle for a range of applications, from humanoid robots to exoskeletons (à la Tony Stark) to prosthetic limbs. However, most solutions have been complicated, expensive and, most importantly, lacking in performance.

Is it possible, though, that the solution to such a complex problem is simple––that it already exists and is easily made by anyone with at least one arm?

A group of scientists at the University of Texas at Dallas discovered that by using polymer threads such as Nylon or Polyethylene (aka fishing line), artificial muscle could be produced, and that it only takes two steps:

Step one: tie a weight to the bottom of some fishing line. Step two: coil it up as much as possible (a step coined “supercoiling”). Presto, you’ve got a cutting edge material.

But what designates this “artificial muscle”?

When heat or electric current is applied to this material, it contracts, just like a muscle does. When the stimulus is removed and the material cools down, it quickly returns to its original length.

However, what really make this mundane material (again, this is still technically just a fishing line) truly remarkable is its unbelievable properties, which make our normal muscle seem like a slouch. Based on the study released by UT Dallas, this coiled polymer muscle can contract by 49%, compared to about 33% for human muscle, and it can lift loads over 100 times heavier than human muscle can of the same length and weight! In addition, during contraction, the average mechanical output power is 27.1 kW/kg, or about 36hp/kg. In plain english, that's 84 times that of our own skeletal muscles. In a report about this artificial muscle, it is referred to as being as powerful as a jet engine.

This really got us thinking… if it’s as powerful as a jet engine, why not make an engine out of it? So we’ve started.

At this point, we’ve just begun to fiddle with some Nylon sewing thread, trying to make our own supermaterial, but the results are already astonishing. What began as a completely inflexible fishing line quickly became stretchy and springy. It was strong and didn’t seem remotely contractible until heat was applied with a heat gun. Although still in its infancy as far as our testing goes, we were still able to observe small contractions, and if the scientific report is correct, we should be able to get A LOT more out of it (again, up to 49% of its original length).

Using several lines to imitate muscle fiber, we estimate being able to generate enough power to produce a running engine. As stated earlier, a kilogram of this muscle can produce about 36 horsepower during contraction. To put that in perspective, many tractor motors are about 12 hp, and some of the first WW1 fighter planes only had about 40 to 50hp. However, unlike those motors, this engine will weigh just over a kilogram: 1 kg of muscle, and the rest made out of just about anything you want (carbon fiber, lightweight plastics…) seeing as there are no explosions or gasoline as found in an internal combustion engine.

Our design plan is very simple. We hope to develop a very basic two-stroke motor (see the diagram), where this artificial muscle replaces the pistons (those metal bits that go up and down). We will be using conductive, silver-coated nylon thread and periodically passing electricity through it to be able to stimulate the artificial muscle and obtain optimal performance from it. We intend on the system to cool naturally; however, we may have to consider blowing cool air over the coiled material to speed up the process. (We’ll keep you posted).

In our eyes, this engine will serve as a proof of concept and as a testament to this material’s versatility and usability. It demonstrates a lack of collisions and explosions compared to its internal combustion brethren as well as a collision between the fields of biology and engineering, which we feel was equally the intention of its creators. Through materials engineering, they were able to produce a material that relays the properties of human anatomy to a plethora of mechanical applications by the discovery of a new property it possess. It has changed how we view polymer threads and what we can do with them.

In fact, it just might be time to find a new name for “Fishing Line”… We're thinking something much more grand, along the lines of Wolverine’s “Adamantium” or Superman’s “Kryptonite.” This truly is a supermaterial.