All materials can in principle be described at the nanoscale. By natural nanomaterials here we maen that materials belong to the natural world (animals and mineral) without human modification or processing, and that have remarkable properties because of their inherent nanostructure.

1. 13-1-2016

2. Outline:
what is a natural nanomaterial?
Shark Skin
The Lotus Effect
Butterfly Colors
Gecko
Toucan Beaks
A Material Stronger than Steel and More Elastic than Nylon?
References

3. what is a natural nanomaterial?
All materials can in principle be described at the nanoscale.
By natural nanomaterials here we maen that materials belong to the natural
world (animals and mineral) without human modification or processing, and
that have remarkable properties because of their inherent nanostructure.

4. Shark Skin
Sharks have been swimming in the oceans for millions of years without the problematic accumulation of
algae and bacteria on the surface of their skin.
This is because the nano-scale patterns on the shark’s skin deflect the accumulation of barnacles,
algae, and bacteria which is called anti-fouling .
Algae and bacteria tend to settle on surfaces and ultimately establish colonies and biofilms. It is
easier to colonize a smooth surface, whereas establishing a biofilm over a rough surface requires
too much energy for colonization and makes signaling between cells in the colony difficult.

5. Shark Skin
These surfaces are essential for maintaining functional pipelines,
ships, submarines, and other submerged infrastructures and
technologies.
Until now, anti-fouling techniques have primarily involved
coating surfaces with chemicals that can be toxic to humans and
the environment, in addition to their bacterial and algal targets.
bufalin (3,4-dihydroxybufa-20,22 dienolide)

6. The Lotus Effect
The superhydrophobic power of self cleaning:
The leaves of the lotus flower exhibit extremely water-repellent properties due to micro and
nano-structures on the leaf surface.
These structures allow the plant to have a magnificent self-cleaning function
This concept has been extrapolated and applied to sealing windshields, waterproofing phones,
and protecting fabrics, wood, and other surfaces from dirt, dust, or car exhaust particle
residue.

7. Butterfly Colors
Butterfly wings are layers of nanoparticles seperated by layers of air.
The thickness of the layers changes the colors that we see.
These nanostructures are coated with hydrophobic wax crystals
approximately 1 nm in diameter.
This makes the surface at the nanoscale quite rough.

8. Butterfly Colors
Besides repelling water (hydrophobic) and color, the nanoscales make butterfly wings
self-cleaning.
= water
= dirt
These nanostructures
don’t just make me
pretty. They also keep
me clean by shedding
water and dirt!

9. Butterfly Colors
1. Depending on what you need, these nanoparticles
might be made into flourescent proteins, DNA,
viruses, or dyes.
2. These flourescent nanoscale polymer fibers might
be used to reflect visible, UV and IR radiation for
cooling or transmit certain wavelengths of light for
warming.
3. They can also used for bar coding or other
functions.
4. The ideas are endless!

10. Gecko:
Geckos have the unique ability to scale vertical surfaces with both strong attachment of their toes to the
surface coupled with easy and rapid removal.
They are able to do this due to the attractive forces of millions of nano-scale hairs on their toes known as
setae and spatula.
These create a “frictional adhesive” to other surfaces by increasing
the surface area of the toe—meaning more of the toe actually
interacts with any given surface.
The attractive forces at play here are known
as Van der Waals forces.
These are weakly attractive forces that exist
between nearly all chemicals and materials.
Geckos turn this weakly attractive force into an
adhesive attraction to be reckoned with by
multiplying it by the millions of setae and
spatulae on their toes.

11. Gecko:
 500,000 hairs per toe
 Hundreds of nanoprojections (spatulae) per hair
 Adhesive force in one foot = 100 newtons
 One dime-sized spot could lift a child
weighing 45 pounds.

12. Toucan Beaks : Strong and Light
 The nanostructure of
toucan beaks inspires automotive panels that could
protect passengers in crashes.
 And inspires construction of ultralight aircraft
components.

13. Toucan Beaks
 The exterior of the toucan beak is made up of
overlapping nanosized tiles of keratin, the
same protein that makes up hair, fingernails,
and horn.
 The interior of the beak is a rigid foam made
of a network of nanosized bony fibers
connected by membranes. This allows the
beak to absorb high-energy impacts.
Keratin tiles glued together

14. Horns such as those of the impala are
made up of keratin covering a core of
live bone

15. A Material Stronger than Steel and More
Elastic than Nylon?
 For 450 million years, spiders have made silk,
protein-based nanomaterials that self-assemble
into fibers and sheets.
 If we figure out how to copy this nanscience feat,
scientists would like to use the material to create
an elevator to space.

17. References:
1. https://www.teachengineering.org/view_lesson.php?url=collection/du
k_/lessons/duk_surfacetensionunit_lessons/duk_surfacetensionunit_le
ss4.xml
2. http://www.ehow.com/facts_5673454_chemical-elements-
keratin_.html
3. sustainable-nano.com/.../natures-nanotechnology-bio-mimicry-
and-maki.
4. www.nisenet.org/catalog/programs/biomimicry_nature_nanotech