SPNs Might Change the World, So What Are They?

Slow it down, Hank

I worked with a type of hydrogel in my one summer of actual benchtop research at Miami University twenty-some years ago, and I certainly never would have imagined them to have the properties described in today's video. I was just looking at the ability of the get to absorb and subsequently release transition metal ions, so I wasn't exploring their mechanical properties, admittedly.

SPNs, in case you were wondering, are supramolecular polymer networks, networks of polymer chains held together by - according to this video - non-covalent bonds like intermolecular forces like hydrogen bonds.

Halfway through the video, Hank makes a turn to a possible application of a particular SPN that was used to help paralyzed rats to regrow nerve cells and allow them to 'walk' again. That's a long way from human trials, but the initial study sounds amazingly promising.

The wonder material of the 21st century | Monica Cracuin & Dimitar Dimov | TEDxTruro

No, I have never wondered why pushing harder on a pencil while I'm writing makes the line darker.

I just assumed that there were more layers of graphite being left behind.

Oh, wait, that's it?

Wow. that's not a great opening question, Dimitar.

Here Dimitar discusses the benefits of adding graphene to concrete to make the concrete even stronger. Then Professor Cracuin steps in and suggests other uses of graphene - electronics integrated into fabrics or even our skin - and graphene-like materials (?). She mentions a material of two layers of graphene sandwiched around iron chloride (a combination she calls graphexeter - after the University of Exeter where she researches) to make incredibly flexible, durable, conductive displays - possibly even 'tatoo'ed onto the skin or integrated into contact lenses.

As an aside, I think this is the first TED talk I've seen that switches presenters partway through.

How N95 Masks Stop Viruses

Last week I lamented the fact that the 'what's in an N95 mask' didn't explain how the various layers actually stopped virus particles.

So I went out and found a video that did a better job of that.

Hopefully this video will help fill in some of the holes in your mask knowledge.

Holes and masks don't go together very well, doncha know?

What's Inside 3M N95 Respirator Masks? Find Out!

I, admittedly, haven't seen masks with exhaust valves in them yet. Interesting.

The video maker takes apart an N95 mask, exploring each level but apparently not looking into any research separately from what he sees under his microscope.

The first layer is polypropylene fibers, seemingly spun-bonded like Tyvek.

Then there's a thicker, rigid layer of also 'randomly' laid fibers. He doesn't tell us what that layer is made of. The layer is repeated.

He mentions - almost in passing - that the mask is electrostatically treated to help trap particles.

The final layer, the one against your face, is made of a mixture of small and large polypropylene fibers.

I do wish he went into a little more details of what the material in the middle layers is, how each layer contributes to the overall function of the mask, and how each layer's material is made. But, it's the best 'what's in an N95 mask' video I've found yet. Thanks to Material Science Girl for the tip on this video.