An international team of researchers has created a new type of artificial muscle using ordinary materials such as sewing threads and fishing line. This new type of artificial muscle is both affordable to manufacture and powerful.
The team, led by researchers from the University of Texas at Dallas, was able to produce an artificial muscle 100 times more powerful than human muscles. The artificial muscle made from thread and fishing line can generate up to 7.1 horsepower per kilogram, which is similar to the mechanical power created by a jet engine used in aircraft.
The team published their findings in the online journal Science. The problem with currently available artificial muscles is that they are often bulky and very expensive to manufacture. Moreover, the current crop of artificial muscles suffers from a slew of limitations such as unsatisfactory efficiency, low life cycle and hysteresis, which makes these muscles totally dependent on very specific circumstances. The new artificial muscle created by the team surpasses many of the limitations seen in previously developed artificial muscles.
To create the fishing line and thread artificial muscles, the team twisted and coiled high-strength polymer fishing line and sewing thread into coiled strands. The muscles contract when exposed to a heat source. When the heat source is turned off, the artificial muscle relaxed.
Human and animal muscles contract by about 20 percent of their total length. However, the new artificial muscle created by the team can contract by as much as 50 percent. Moreover, these artificial muscles can contract and relax millions of times, which means they don't need to be replaced often.
The application opportunities for these polymer muscles are vast," said UT Dallas Robert A. Welch Distinguished Chair in Chemistry and NanoTech Institute Director Dr. Ray Baughman, one of the co-authors of the study. "Today's most advanced humanoid robots, prosthetic limbs and wearable exoskeletons are limited by motors and hydraulic systems, whose size and weight restrict dexterity, force generation and work capability."
As previously mentioned, current artificial muscles are often very bulky. However, with this new type of artificial muscle, even a strand of coiled and twisted thread and fishing line which is only 10 times wider than the width of a human hair, can lift up to 16 pounds. A small bundle consisting of 100 strands of artificial muscles will be able to lift up to 1,600 pounds. This amount of lifting power can be used in a wide variety of practical applications.
"We have woven textiles from the polymer muscles whose pores reversibly open and close with changes in temperature. This offers the future possibility of comfort-adjusting clothing," said study lead author Carter Haines, a researcher from the NanoTech Institute in UT Dallas.