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This is a great
time for me to tell you

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about my why this matters.

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And, of course,
the sp2 carbon atom

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matters because of
drinking water, of course.

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And, you know, this is a well--

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in a district in India where
more than 50% of the wells

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exceed the WHO
limits for arsenic

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by around a factor of 5.

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1.8 billion people in the world
drink fecally contaminated

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water on a daily basis.

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600 million people boil
their water in the world.

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Boiling doesn't help
with arsenic, though,

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arsenic just stays
in the boiled water.

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It kills bacteria, but it
doesn't help with toxic--

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toxic elements.

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If you look at the
world as a whole,

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and you look at sort of
where there are water--

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water crisis, where the water
crisis is at this level,

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it's a little over 3
and 1/2 billion people.

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And in those countries,
almost 185 or so countries,

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where this is a
serious problem, if you

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look at the cost of disease,
and the cause of death

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in those countries, 70% to 80%
of all disease and almost 30%

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of all death can be attributed
to the water quality.

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Right.

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So when I talk about
water as a problem,

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I really mean it's
a serious problem.

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It's a problem of life or death.

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Now, this is-- to get
fresh drinking water,

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if you look at the planet,
and you say, well, where

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is the water on this planet?

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Where is the water
on this planet?

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I like this picture because we
consume water volumetrically,

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not in an area, right?

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We use water as a
volume, and this

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is the water we have on this
precious planet as a volume.

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This bubble here is
all of the ocean water.

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It's about 70-- it's about
97% of all the water.

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That bubble there is freshwater
that is inaccessible.

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It's frozen.

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And this one here, you
can't really see it,

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there is another dot there.

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That's less than 1%
of the world's water.

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That is our drinking
water ecosystem

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that is what we are destroying.

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And-- so what--

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OK.

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So there's a lot of things
we can try to do about this.

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One of the things
we can try to do

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is to see if we
can tap into this

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in a way that's more
affordable and more efficient.

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Because there's a lot of water
here, right, and use that.

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But the problem is, if you look
at the cost of desalination

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today as opposed to the
cost-- that's desalination.

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If you look at the
cost as opposed

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to just digging
water out of a well,

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like the one I just
showed you in India,

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it's over a factor of 10.

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Still.

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And, in fact, one of the
big issues with desalination

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isn't just the total cost
or the operating costs,

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but the capital cost.

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How do you build this
plant in the first place?

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And so it takes too much money.

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If you look at the thing that's
at the heart of desalination,

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it's a filter, right.

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It's a filter.

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And I talked about
this in my last,

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why this matters, when I
talk about separations,

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and I promised that in my
next why does this matter,

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I'd talk about water.

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Right.

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Which is what I'm doing.

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If you look at a
desal plant, this

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is one of the world's largest,
this is a plant called

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the Hadera plant
in Israel, and you

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look at what their costs
are that-- remember,

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the costs digits-- half of that
cost-- almost half of the cost

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isn't just energy.

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And almost all of that energy
is in pushing salt water

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through a filter.

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Through a membrane.

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That's called a reverse
osmosis membrane,

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because you're going against
the osmotic pressure.

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And if you look at
the membrane itself--

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this is a picture
of it, it's actually

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a very small layer on top
of this active layer that

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does all the work--

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it's not a very good design.

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In fact, membranes for
desalination are pretty bad.

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Right.

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They kind of do everything
worse than they should,

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except that they work, which
is good, and they're cheap,

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$1.00 a square foot.

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But, see, they're very--
they take much more energy

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than you need.

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They foul up very easily.

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And then that means stuff
gets kind of, you know,

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stuck in them.

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And then you can't take
it-- you can't clean them

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because these polyamide
membranes, which

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are the same polymer used in
these membranes for 50 years,

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haven't changed, the material.

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Those polyamide membranes
are destroyed by chlorine.

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So even in a desal
plant-- in a desal plant,

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if you have drinking
water in your feed stream,

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drinking water has six
parts per million chlorine.

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That's not much.

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They still will go through
the cost to remove it.

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They will remove
it from the feed.

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Why?

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Because if you leave that little
amount of chlorine in the feed,

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these membranes get destroyed.

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By the way, there's 40,000 of
these membranes in this plant.

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Each one is 2 meters long
and 40 square meters of area.

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So-- so these are so delicate
that you can't really

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clean them well.

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And that's part of what the
cost of a plant involves.

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That's part of what the
cost of a plant involves.

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Now, this would be like
a plant, right, you

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have sea water coming in
and, you know-- and then

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you've got your membrane
module that's taking

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the salt out of the water.

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And then the product water.

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But because this
filter is so delicate--

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there's the picture--

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because that filter
is so delicate,

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you actually have to add a
whole lot more to the plant.

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So much of a desal plant
is built around essentially

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protecting this membrane.

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So that's cost.

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That's cost.

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Right.

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A better membrane
could change this.

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But like I said, the
membrane-- oh, there it is.

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You can't Snapchat on that.

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Snapchat?

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What is it that people do today?

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Not Snapchat.

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Yeah, Snapchat.

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Yeah.

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OK.

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Thank you.

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You can't Snapchat on that.

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That's what I meant.

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I know it's not My
Space, but I don't know--

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but, anyway, this is like even--
you know, when I look at--

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at membranes today as a
material scientist and materials

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chemists, all of your
membranes, I think,

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that's what it looks like.

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Why?

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Doesn't have to be the case.

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We can do so much better.

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And so-- OK.

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Energy costs goes into
pretreatment, secondary

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treatment, and this is
where this comes back.

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This beautiful material that
we have now understood more

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than we did before.

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Because, remember,
before I showed

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you graphene and I showed you--

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no, I showed you benzene.

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And we talked about it as
a Lewis resonant structure,

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remember?

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Right.

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A Lewis resonant structure to
help explain how it looked.

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You know, gra-- graphene does
not have alternating bonds.

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Remember, that's what
we talked about before.

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It's a Lewis resonant structure.

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So it lowers its
energy by having

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two sets of structures that
have sort of alternating bonds.

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We talked about it in
the context of benzene.

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But, see, now you
know so much more.

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You know so much more.

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Because, now, you know why
graphene is so special.

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You know why graphene
is so special.

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It actually is
the hybridization.

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It's the hybridization.

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Because on top,
and on the bottom,

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of a single atom of a
single sheet of graphene,

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you've got pi
bonding all the way.

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Those pi bands are going
across the whole surface.

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And those electrons
are critical.

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Those electrons that
occupy those [INAUDIBLE]

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are critical to the very special
properties that graphene has.

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So you now know the secret.

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It's sp2 hybridization.

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And, you know, this
has allowed us--

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this has-- you might
tell I'm kind of

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passionate about this problem.

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Partly impassioned passion
about a lot of problems

191
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but, also, we happen
to work on this,

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and we have been
developing this.

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This is like the
ultimate membrane.

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I can soak this in
chlorine overnight.

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I can put it in
negative pH solutions.

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I can heat it up.

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It doesn't degrade.

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And we have figured out
how to poke holes in it

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at just the right
size, or to stitch it

200
00:08:28,607 --> 00:08:33,578
together so that maybe you can
filter particles by the flow

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00:08:33,578 --> 00:08:35,313
in between these sheets.

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Right.

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00:08:37,048 --> 00:08:38,650
And this material,
as a membrane,

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is so promising
that we've actually

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00:08:41,886 --> 00:08:44,623
started to commercialize
it as of the last year.

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00:08:44,623 --> 00:08:46,992
And I think this is really
going to make a big difference

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in a lot of areas.

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Why?

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Because of sp2 hybridization.

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That is why.

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That is why this is
such a special material.

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OK.

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That's my why this matters.