I was wondering why carbon nanotubes are not used as artificial muscles yet? I mean they behave similar to real muscles, only that they expand horizontally. What are the current challenges that researchers are facing?

  • $\begingroup$ do they shrink or expand if a electrical charge or current is applied? $\endgroup$
    – Solar Mike
    Aug 7, 2018 at 18:31
  • $\begingroup$ Sure, we went to the moon, why not? $\endgroup$ Aug 7, 2018 at 18:46
  • $\begingroup$ Young's modulus of muscle fibre: approx. 25kPa. Young's modulus of CNT: approx. 1TPa. Only a factor of $10^8$ difference to worry about - nothing important ;) $\endgroup$
    – alephzero
    Aug 7, 2018 at 18:51
  • $\begingroup$ they expand if electrical charge is applied. $\endgroup$
    – John Doe
    Aug 7, 2018 at 19:16
  • $\begingroup$ @alephzero nothing important indeed, you need a factor of 10^8 less tubes than the muscle fibers you ar replacing. $\endgroup$ Aug 8, 2018 at 8:50

2 Answers 2


This is simple and hard to answer at the same time since I couldn't find sources clearly discussing the reasons behind it.

  • This is what I could find:

Carbon Nanotubes aren't widely used because they can't be mass-produced.

The biggest problem of carbon nanotubes is its production method, it is incredibly expensive, you really can't mass produce it and there are many variables that can make the whole process not reliable nor repeatable. The last big breakthrough on the production of carbon nanotubes was 3 years ago and it was growing 12cm of it uninterrupted for days, and to me, it seems like it would need some post-processing.

The other thing it comes to mind is this 10 years old video were Ray Baughman explains that the principle of CNT actuators, which seems to be incredibly simple. On a recent video of his, Ray Baughman explains other types of actuation of Carbon Nanotube artificial muscles and their pros and cons.

What he describes in the first video makes me remember of the principle behind Lorentz Force, which is a phenomena that can happen with conventional power transmitting cables. And as such, I would imagine that the carbon nanotubes have an advantage for being nano-sized and electrically conductive, which allows a bigger magnetic strength due to its proximity to between the fibers.

By the way, lorentz force isn't that strong, neihter that efficient, which further puts into question on why make an artificial muscle that is expensive and inneficient.

In any manner, I hope my answer was useful.

  • 1
    $\begingroup$ That's the reason why we don't have carbon nanotube anything yet...from artificial muscles to space elevators. $\endgroup$
    – DKNguyen
    Jan 1 at 1:30
  • $\begingroup$ @DKNguyen I just hope the guy appears soon and accept my answer, lol $\endgroup$
    – Fulano
    Jan 1 at 12:50

Carbon nanotubes are brittle. Though they have high tensile strength, their lateral strength against direct forces it's meant to Support is poor. It makes a great cable; but a terrible brace.

More case, despite the fact they've been in development for many years, overall manufacturing capacity is still in it's infancy. Making it too expensive to fabricate a single kilogram of material.


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