Everyone’s favorite viscoelastic non-Newtonian fluid has a new use, besides bouncing, stretching, and getting caught in your kid’s hair. Yes, it’s Silly Putty, and when mixed with graphene it turns out to make a dandy force sensor.
To be clear, [Jonathan Coleman] and his colleagues at Trinity College in Dublin aren’t buying the familiar plastic eggs from the local toy store for their experiments. They’re making they’re own silicone polymers, but their methods (listed in this paywalled article from the journal Science) are actually easy to replicate. They just mix silicone oil, or polydimethylsiloxane (PDMS), with boric acid, and apply a little heat. The boron compound cross-links the PDMS and makes a substance very similar to the bouncy putty. The lab also synthesizes its own graphene by sonicating graphite in a solvent and isolating the graphene with centrifugation and filtration; that might be a little hard for the home gamer to accomplish, but we’ve covered a DIY synthesis before, so it should be possible.
With the raw materials in hand, it’s a simple matter of mixing and kneading, and you’ve got a flexible, stretchable sensor. [Coleman] et al report using sensors fashioned from the mixture to detect the pulse in the carotid artery and even watch the footsteps of a spider. It looks like fun stuff to play with, and we can see tons of applications for flexible, inert strain sensors like these.
[Thanks to Pez for the tip]
It’s nice to see things that are within the price range of your normal experimenter for a change
Supplementary Info:
http://science.sciencemag.org/content/sci/suppl/2016/12/07/354.6317.1257.DC1/Boland-SM.pdf
Nice thing is graphene powder is pretty cheap.
No! Putty is not silly! :)
there, they’re, their.
This looks like a case of voice recognition without proofreading. My old editor used to say “if your writing is not important enough to you to read, what makes you think it is important enough to someone else to read.”
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Far as I know, Silly Putty IS silicone oil and boric acid. That’s how it was invented, completely by chance.
I tried this, and my putty still had infinite resistance. I got “ultra conductive graphene flake powder” from amazon and mixed it with a ratio of 1 gram of graphene to 50 grams of putty. Am I doing this wrong, or is my graphene not real? The seller wont respond, and my putty looks very similar to that of the video. Any tips guys?
Thanks
Is the material conductive before you mixed with the putty? What is the before resistance?
I did the same thing, had success melting them both in acetone first. Full recipe here: https://www.instructables.com/id/Goophene-Hypersensitive-Graphene-Sensors/
Did a similar experiment with graphite powder (aka lock lubricant) and various glues, found that the best one was cycle adhesive that shrinks when cured. That one works well.
What brand of cycle adhesive?
I made a DIY version of it that seems to be working pretty good! https://www.instructables.com/id/Goophene-Hypersensitive-Graphene-Sensors/