This scientist is creating a new, and highly specialized type of aerogel using a wonder
material we know and love… graphene. While this material is mostly comprised of air,
it also boasts graphene-like properties that make it both super strong and electrically
conductive. This means that the aerogel you're looking at could completely revolutionize
material sciences—even blazing a trail for in-space manufacturing. Which is why scientists
are now looking to synthesize this new material on the International Space Station. Because
in the absence of gravity… strange things can happen.
Microgravity just unlocks a completely new area of material science.
It's a brand new knob that we've never had
access to before. You could potentially have new properties. We might uncover new types of underlying physics.
These scientists are working on an experiment to go onboard the ISS, that if successful,
could have huge impacts on in-space manufacturing... and future deep space missions.
So what exactly makes graphene aerogel so special? To understand that, we
have to look at its component parts—starting with graphene. Graphene is composed of the
element carbon and it's actually just a single atomic layer of carbon in a honeycomb lattice.
Graphene is an amazing material because it is strong— stronger than steel. It’s also
electrically conductive, so carriers can transport within graphene at really fast speeds.
It has applications in energy storage, like batteries or super capacitors.
There’s been a ton of hype around graphene, with many calling it a “wonder material.”
And after years of R&D, we’re just starting to see it leave the lab. But it’s not the
only material getting hype. There’s also aerogel. Aerogels are a class of materials
that can be made out of pretty much anything. Like sculptures can be made out of stone or
clay, and very similarly, aerogels can be made out of these different raw materials.
Which opens the door to nearly limitless possibilities. Aerogels are almost completely made out of
air. And are considered one of the lightest solid materials ever known. The most popular
type of aerogel is silica based. Silica aerogels have been used by NASA in the Stardust mission.
NASA utilized this material because it was lightweight and also had a porous structure
such that they can capture this space dust material.
Silica aerogels have also been used as insulation on NASA’s Mars rovers... and are even being
used as insulation for thinner, warmer outerwear here on Earth. This material tends to get
the most attention, and sometimes gets mistaken as the one and only aerogel. But aerogels
can also be made out of metals, polymers, and of course graphene... which brings us
to the XLab. In the XLab—the EXtreme Environment Microsystems Laboratory—we make tiny but
tough electronics and materials. Like graphene aerogel, which has the super strength and
electrical conductivity of graphene, in the form of a light aerogel. There's two main
steps in creating graphene aerogel. The first is to create the graphene hydrogel. And so,
you start with graphene oxide flakes and you disperse those in an aqueous solution. And
then once you have your graphene oxide dispersion, you can load that into a furnace and heat
that to about 200 degrees Celsius. And that will form your hydrogel. It's honestly exactly
like making Jell-O where you put in the powder and then you add the hot water and you let
it cool and you have a Jell-O. And so, a hydrogel is the graphene Jell-O. And then, the second
part is taking away the liquid from that and leaving just air in the structure. Making
a graphene aerogel is special because of its two-dimensional nature. And so making a graphene
aerogel allows us to study the way two-dimensional flakes or a sheet interact with each other
when we bind them together. And the atomic structure of a material determines its different
properties. Which is why--despite the fact that diamonds, pencil lead, and graphene are
all made entirely out of carbon--they each have very different characteristics. And then
there’s gravity. Scientists are eager to solve the mystery of how the structure of graphene aerogels
will behave in microgravity. To find out, Debbie’s team is preparing to send a payload
to the ISS with all the necessary components to make graphene aerogel in space -- basically
using the same two-step process outlined earlier. The first step, making the hydrogel, is actually
the one we're interested in for the space station. When you're dealing with liquid to
solid phase transitions, there are concerns you have to worry about, especially with dispersion
with the powder, because gravity is going to pull those down and that creates an anisotropic,
or unevenly distributed graphene hydrogel, which then gives you an unevenly distributed
graphene aerogel. And that, in turn, affects the properties, so you could have with that
less electrical connectivity, lower absorption. The International Space Station is, of course,
in outer space. So gravity’s effects are minimized. The flakes are free to float around
homogeneously, and when we perform the reduction step in the furnace on the space station,
that will give us a more uniform macro structure. Synthesizing graphene aerogels in a microgravity
environment is really exciting because it can potentially advance many of our engineering
applications such as the development of batteries, the development of thermally insulating materials,
and also sensor materials. We are currently about one year into the project and so we
are hoping, fingers crossed, to launch our payload within the next year. Once we get
the payload back, we hope to learn, number one, what is the mesostructure of a microgravity
synthesized aerogel? So structurally, what does it look like? Is it different from an
Earth-based material? We plan on measuring the mechanical properties, the thermal properties
and the electrical properties of the aerogels and compare the Earth-based properties to
the microgravity-based properties. Equipped with this knowledge, if researchers can crack
how to manufacture graphene aerogels in microgravity, then the way we explore space could change
completely. The idea is to take raw materials, bring it up to the space environment, build
what you need, and then deploy it from space. So that's the big vision there. While we’re
not at that point yet, this graphene aerogel experiment is moving us towards that possible
future. So I think some of the first demonstrations and first validations of our work could happen
within the next 5 to 10 years. The thought that a new era of materials science is just
around the corner, which could in turn herald a new era of human space exploration, is a
thrilling concept for Debbie and Jessica.
It's just cool, it's the new frontier, it's just unexplored, it's
the future. When I take a step back and think about the potential to do these experiments
in space, it's really fascinating and exciting and I think the people I work with are really excited too.