Kind: captions
Language: en
I feel confident.
You You're confident that I am not going
to be damaged.
Not permanently.
Okay.
Let me back up for a moment. I want to
talk about the properties of Aerogel,
the world's lightest solid.
What I'm going to do is I'm going to
lean in. So, it's coming in through this
mic. And then, can you do that again?
Yeah.
This is what it sounds like.
That is weird.
It has a metallic ring. First recognized
by Aerajel's inventor, Samuel Kistler,
all the way back in 1931. Now, Aerajel
is an excellent thermal insulator, but
it's not the easiest material to work
with.
Can I try it?
Sure.
Oh, I didn't I don't quite have the the
touch.
Why can't I make it ring?
Oh, no.
And look, it didn't take a whole lot to
break it, right?
It breaks pretty easily. So, is there a
way to take the extraordinary thermal
insulation of Aerajel, but make it more
usable?
Uh, what I put together here is just a
combination of aerel particles, silica
aerogel particles, and a nonflammable
binder. Uh, and you should be able to
put it on your your skin and hit
yourself with a torch.
Should Right. We'll give it a shot.
Okay.
So, here, just take a little bit and
squeeze around your finger.
Just around?
Yeah, just squeeze it around your
finger.
One finger or two fingers. Doesn't
matter.
How's that? Am I Am I doing it wrong?
Oh, yeah. That's That's Yeah, that'll be
good. You just want to make sure that
the fire when it goes around your finger
doesn't uh hit the bare skin.
It seems like it's pretty thin around
this fingertip here. Like, how thick
should it be?
You're making You're making me nervous
holding a blowtorrch.
Can I do the the the the blowtorrching?
Oh, you can do the blowtorrching.
Absolutely.
Cuz I mean, if this is if this goes
wrong.
So, how hot is a blowtorrch flame? Well,
it's really hard to tell with the
thermal camera, but from our experience,
it's usually, you know, at least 1500°
C, and it can get as hot as 2,000.
So, yeah, this is very hot. All right,
let's try it. This is so wrong.
Should be very hot there.
I, you know, it looks like I'm toasting
a marshmallow. Wa. Why is it uh flaming
like that? And what is burning? Uh,
is the binder running out?
Correct. You should be able to just hold
it right on there.
You feel hot?
Uh, it doesn't feel hot at all. My
finger does not feel hot at all. That is
insane. So, what's the how wide or
proprietary?
Proprietary.
I cannot believe how little warmth I
feel passing through that. The Fleer
1020 thermal camera has different
temperature ranges. And here, the Aerel
is clearly hotter than the 160° C upper
limit. I mean, it's glowing orange hot.
So, it's clearly incredibly hot. I mean,
if you can see the black body radiation,
you know that it's very hot. So, we went
to the highest temperature range. So,
this goes up to 2,00
uh 881 9007.
Uh 9007
97°
C.
That is absurd. Pretty hot.
Right in front of my fingers.
What?
So, this uh was was about almost 1,000
Celsius, but behind this thin layer of
aerel,
my fingers are just just warm.
Yeah, it's at 31°.
Wow. Are you a believer?
I mean, it is clear this stuff
insulates. This video is about taking
Aerajel's extraordinary properties and
improving on them. For example, I'm
about to step into this pool without
getting wet.
I think there's a layer of air there
right next to my skin. That thin layer
of air is what makes my skin look
silvery. Light from certain angles
reflects off the water air interface in
what's called total internal reflection.
That is very strange.
This is a really cool effect. I mean,
just besides the fact that I'm I'm
basically waterproof. I feel like this
extra air on me is making me more
buoyant than usual.
Let me try coming out of the water and
see if I'm still dry.
That is trippy.
I don't I don't really feel wet at all.
That was weird. That's really weird.
So, how did I make myself waterproof? I
did it with a gel particles by taking a
bucket of them and coating myself with
the tiny dust. But this is a kind of
strange way to become waterproof because
normal silica aerogel is hydrophilic.
There we go. Now this is a hydrophilic
aerogel. So all those O groups inside
the aerogel are absorbing the liquid and
causing the aerogel structure to
collapse.
Aerogel is really good at absorbing
water for two reasons. First, it
contains a lot of surface area due to
its nanocale spongelike structure. An
ice cube- sized piece of aerel contains
half a football field of surface area.
That makes it good at absorbing lots of
molecules. Something scientists have
sought to exploit. My favorite
application, which I I still think today
is a good idea, is what's the idea is a
a physical insecticide. So most
insecticides work by being neurotoxins.
They're called choline eststerase
inhibitors. It's the same mechanism as
nerve gas and we spray this on crops and
things. But a physical insecticide works
by basically getting stuck to the outer
skin of the insect and and basically
sucking all the moisture the or the oils
uh out of them to the point where they
they just sort of
dry out to death.
It's kind of like uh putting salt on a
slug or something like that.
That's the very good analogy. Exactly.
The other reason it's good at absorbing
water specifically is because its
structure is covered with O groups which
attract water molecules and that makes
it ideal for use in museums.
In the past, I've been working with a
company in Italy called Gopion uh which
makes museum cases and they made the
case for Mona. They are interested in
putting aerogels in the cases because
it's a passive moisture regulator
essentially. Once you have it inside, if
the moisture increases, the aerogel
absorbs a lot of it. If it decreases, it
releases some of it.
Aerajel's ability to absorb is even
being used right now to help detect Mars
quakes.
These were the ones that were made for
the NASA Insight mission.
This aerel looks like chalk because
so-called zeolyte particles are
dispersed throughout it. They can absorb
moisture even at very low pressures.
There is a seismometer that contains
three small seismometers and it requires
since they're so small um they require
exceptional vacuum inside otherwise the
motion gets damped. So that's what we
developed this for. Uh the zeulites were
helping absorb the moisture
predominantly that was coming off of the
epoxies and cable gas and different
things.
So that is it's sort of maintaining the
vacuum by keeping to pulling things.
It's essentially a vacuum pump um if you
think of it that way. And uh what's
interesting about it is it doesn't
require any power any consumption. It's
very light. So essentially this is what
enabled the inside mission to work.
Aerel can absorb up to 25 times its
weight in water. But for some
applications this is less than ideal.
So once we've done this is that piece of
aerel ruined now
pretty much. Yeah. That's that's entropy
uh irreversible damage there. To to
counteract this issue we take a
hydrophob. It's a reactive chemical that
when it touches an O group spontaneously
rearranges with that O group and creates
this big nonpolar group and that repels
water. So by replacing just 30% of the O
groups that line the inside of the
aerogel with these hydrophobic groups,
you can make an aerogel that perfectly
repels water. So here water bounces off.
It's totally impervious. Uh, it does not
penetrate in and it can sit on water for
months and it will be just the same as
if it was never wetted at all. You
ready?
I guess. Let's give it a shot.
There it goes.
It feels funny cuz it like it hardly
feels like the water is touching me cuz
in a way the water isn't touching me.
It's not touching you. That's what's
amazing. At the molecular level, it is
being repelled.
Look how crazy that it's like a weird
laminer flow.
This is so trippy. So aerel can be made
impervious to water or more absorbent.
It is naturally brittle, but it can be
worked into a sticky paste. And so far
I've really only focused on silica
aerel, but aerel can be made out of all
sorts of different materials. So all of
these materials are nanoructured. That's
right.
And they have nanoized pores around 20
nm in size.
That's right.
And they are over 50% air.
Correct.
Which is why they're all so light.
Lightweight. That's right.
Some of them are made of polymers. And
there is a trade-off between thermal and
mechanical properties.
A traditional silica aerogel is
typically around 15 m per meter Kelvin
thermal conductivity. So that means
about three times two to three times
better insulating than styrofoam. These
materials would be between one and a
half to two times more insulating than
styrofoam. Somewhere around 20 to 26
matt per meter kelvin. This is a
polyimid aerogel. This chemistry came
from NASA. So it's a great insulating
material. U but it's nonflammable. Knock
on it. It feels like wood. Internally we
call it Martian tape. Another way to
make a gel more workable is to
incorporate it into composite materials
like blankets.
Something that's in between silicone and
silica.
That feels nice.
It feels very nice, doesn't it?
This feels like uh almost like a um
stuffed animal.
Yeah, exactly. So, this is a um new type
of aerogel blanket that in the future uh
we may find in something like an
astronaut suit or maybe even apparel.
What this material is actually it's
fiberglass.
It does feel like fiberglass. fiberglass
that's been infused with aerogel. And so
that fiberglass aerogel composite. So
because aerogels are traditionally very
fragile by compositing it with the
fiberglass allows you to make something
that can be flexed and cut and sewn and
wrapped. It's not the most cuddly. It it
sheds dust when you tap on it. But
what kind of dust is that coming?
It's silica aerogel. It's amorphous
silica and it's it's very safe. It's not
for example like quartz fiber or
asbestous which are you know long aspect
ratio fibers that the body has no
chemical means or physical means of
breaking down. This stuff is readily
captured and and expelled by the body
and it's it's not dangerous. And this is
what they use to insulate subc oil
pipelines and refineries and all sorts
of applications. So
just that thickness will insulate a
pipeline.
Yeah. So that thickness that one this is
1 centimeter thick. in one centimeter um
you get the same effective insulation
value as 3 cmters over an inch of
mineral wool or fiberglass by itself.
So, it's a tremendously
uh uh better insulator. This blanket is
actually what I'm going to put to the
test in the final episode of the Aerajel
trilogy. So, subscribe if you don't want
to miss it.
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