Can non-Newtonian fluids help make a better iPhone case?


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D3o is a pretty interesting material.

My major objection is that (at least when I checked last time) it is pretty much impossible to get a sample. The vendor sells only and exclusively to big brands.

There should be a DIY variant and/or a knockoff Chinese producer. I’m willing to give the original vendor my money, if they wouldn’t ask for an excessive amount, but if they don’t want to sell me a small piece, they deserve all the knockoffs the market can bear and then some.


They seem to have provided it to folks for reviews. There are lots of videos of folks hitting their fingers wrapped in D30 putty with hammers. I’d love to have a Sugru version of this!


I believe it should be possible. A composite, with Sugru as the matrix, and a suitable non-Newtonian fluid as the dispersed phase. Now, what fluid to use… Most likely something with long molecular chains with significant but weak-ish mutual interactions. Starch is a common one for demos, maybe high molecular weight polyethyleneoxide could work too? (short google search says apparently yes… but what’s what the pros use?)

Edit: Some other classical mixture in use is polyethyleneglycol with suspended silica nanoparticles (I saw 120 nm sized ones).


The video has 2 problems:

  1. backwards grease pen writing is tedious and annoying

  2. there is no way to tell if the black cylinder under the tile is a hollow pipe during the D30 tests. It seems like there would be no reason to hide this, other than to falsify the results by substituting a solid cylinder for the pipe section shown in other tests.

D30 might be all that it claims, but the video is not convincing.

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Why is this case any better than the apple-made leather ones? The issue with phone breakage isn’t the sides or the back, it’s the screen - any case you get can protect the stuff you don’t interact with.

If the advantage is cost, okay. But I don’t see how this case does anything NEW.

I have had Tech21 cases for my iPhone 5S and 6 and I’m clumsy as heck, dropping them at least a couple of times a day. Both survived that abuse without any problems in those cases, they also stick out just enough on the front of the phone that the glass doesn’t hit the floor. They are also pretty comfortable to hold and decent to look at (though I wish I could have found the 6 case in the orange goo color - I thought it looked nice against the white phone).


The purpose of using a non-newtonian fluid in personal protection is that it is flexible. It can conform to an arbitrary shape. You can flex and move until the shear rate exceeds a threshold. Then it acts like a rigid solid

For a phone, it’s silly. Phones are, so far, rigid and have a fixed shape. There’s no advantage to using non-newtonian fluid. Unless you just like having a squishy case. Otherwise, plain ol’ plastic cases work the same.

After several screen replacements, I went looking for a different kind of case. I was sold on the tech21 when the Apple Store employee flung his phone across the store in a freaky non-Newtonian demonstration. Now it’s also on the spouse’s phone and no more screen replacements. Also provides some “grip” without being squishy or too bulky. Obviously won’t save the screen from a direct hit with a blunt instrument, but for the average tumble to a floor or pavement, the D3o does a nice job of soaking up the shock.

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Ahem, I think it’s pronounced D20, not D30.

Wait, were you trying to spell C3PO?


It’s actially D3o, the last character is o as lowercase “oscar”, not a zero.
(…that’s what we got for zero not being taught to be written with a slash across, or at least a dot within.)

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