- [Matt] You're looking at an unsinkable metal.
Watch it again.
Even if you hold it down, it pops right back up.
This is not an illusion.
Researchers at the University of Rochester
made this metal object buoyant
by taking inspiration from nature,
specifically from rafts of floating fire ants.
The metal was etched with a crazy-powerful laser,
making it superhydrophobic, or extremely water repellent.
Even if you poke it with holes,
it still rushes to the surface,
meaning you could conceivably build
unsinkable ships with it.
To learn more about the technology we sat down
with one of its inventors.
- My name is Chunlei Guo, I'm a professor
in Optics and Physics at University of Rochester.
- Describe for us what you have done in this new project.
- In this project, it's actually a following
of work we did a number of years ago.
And at that time we developed this so-called
superhydrophobic surface.
We used ultra-fast laser pulses
to process material surface
so the surface will consist of a range of microstructures
and nanostructures.
They can trap a lot of air by the surface structures,
so essentially we have an air cushion
right on top of the surface.
- So how do you then use these superhydrophobic materials
to create something that's actually unsinkable?
- So we start with our super hydrophobic surfaces,
we arrange them facing each other,
and then there's a air gap in between.
So this structure trap a large amount of air
and then the whole thing will have effective density
less than water.
So it has a very high buoyancy.
It will keep floating back up.
- And you could even damage the structure,
you could poke holes in it
and it would still float?
- Yeah, absolutely.
The reason for that is
if you puncture the surface, it's only that part will,
the water will come in.
But the surrounding area will still
have the super hydrophobic property,
will still keep the water off
the remaining sections, and they can still float.
Therefore, in principle, you can punch as many holes
as you want, you can reduce this to zero
and the structure will still be able to float.
- And my understanding is that you had some inspiration
here from nature?
- One type is Diving Bell spiders,
the other type is fire ants.
The common feature is they both have
some superhydrophobic body surfaces.
For the spider, they live their entire lives
underneath water
but they still need to breathe air,
so what they do is they periodically come to the surface
and then, and they use their hydrophobic body
to grab some air and then trap the air
and underneath the water they will breath into this water,
this air bubble,
so they can live underneath the water.
And for fire ants,
so the fire ants have, also have these
superhydrophobic body surfaces.
They grab onto each other and form a raft
and this raft will keep them afloat
because the large amount of air
trapped between their body surfaces.
- So, is this thing actually unsinkable?
- This structure, from the extensive experiments
we have done is unsinkable.
And as long as we keep this integrity
of this metallic structure,
and you will not be able to push it down.
Of course, if you rip open the metallic structure
the superhydrophobic surface is sinkable, okay?
You can easily push down the superhydrophobic surface.
We did experiments with submerges,
forced a submerge, for two months.
And as long as you release the load,
it sprung back up again.
You know, we haven't had time to test it
for, you know, permanently yet.
But based on the, all the evidence,
everything pointed to it's extremely,
highly, highly floating.
- Can you walk us through what kinda laser you used
here to etch this metal
and how it went about creating
this superhydrophobic surface?
- The laser we used
is a so-called femtosecond laser,
and femtosecond is a one-millionth of a billionth
of a second.
Extremely short time bursts.
Within this sort time burst,
the peak power of the laser pulse is extremely high.
It's actually equivalent to the wattage of the entire
North American power grid.
The laser pulse that just delivered
this extremely intense pulse onto the surface
and instantaneously it can transform a smooth metal surface
into a highly textured one.
- Beyond the lab, with this little tiny piece of metal,
where might it be applied in the future?
- With a large laser, faster scanning speed,
we can speed this up and really make it
in a much larger scale.
And apply to applications such as ships and ocean vessels.
And also flotation devices for electronic protections
when those electronics have to deploy at sea.
- So say you were to scale this up
into something like a larger structure
that you want to be unsinkable,
could theoretically a really heavy load
weigh it down?
Kind of as you have done in the lab
to make it actually sink?
- So the current ship,
they have this structure,
they basically displace a large amount of water
with the heavy load, right.
The problem is once the ship get damaged,
the structure itself will not be afloat
and that part in the ship eventually will sink.
Our structure, we can also make the ship hull
with our metallic assembly.
And we still can benefit the same unloading capacity.
We still can make the same shape,
but a difference is, if there's a damage,
the metallic structure itself
is able to survive.
- Thank you for takin' the time.
- Thank you for your interest in our research.
[gentle xylophone tones]