5. Nanoscience Vs
Nanotechnology ?
Nanoscience is the study of phenomena and manipulation of
materials at atomic, molecular and macromolecular scales,
where properties differ significantly from those at a larger scale.
Nanotechnology are the design, characterization, production
and application of structures, devices and systems by controlling
shape and size at the nanometer scale.”
7. Feynman’s speech
There's Plenty of Rooms at the Bottom, 1959
it was possible to create "nano-scale“ machines,
through a cascade of billions of factories
• “Why cannot we write the entire 24 volumes of the
Encyclopedia Britannica on the head of a pin?”
•
Dr. Richard Feynman, one of America’s most notable physicists,
1918-1988.
8. Dr. Feynman, Continued
• “The problems of chemistry and biology can be
greatly helped if our ability to see what we are doing,
and to do things on an atomic level, is ultimately
developed – a development which I think cannot be
avoided.”
9. Eric Drexler,
Cell Repair Machines
• “By working along molecule by molecule
and structure by structure, repair machines
will be able to repair whole cells. By
working along cell by cell and tissue by
tissue, they…will be able to repair whole
organs…they will restore health.”
•- Drexler, 1986
X
10. Buckyballs
Three gentlemen—Harold Kroto from the
University of Sussex, Robert Curl and Richard
Smalley from Rice University—
were awarded the Nobel Prize in Chemistry in
1996 for their discovery of a new composition
of carbon, Carbon 60.
11. The nanometer scale
The nanometer scale is conventionally defined as 1 to 100 nm
“fluid”
Often objects with greater dimensions (even 200nm) are defined
as nanomaterials
One nanometer is one billionth of a meter
13. Understanding Size
- Our fingernails grow at the rate of 1 nm per second.
- The head of a pin is about 1 million nanometers across.
- A human hair is about 80,000 nm in diameter.
- A DNA molecule is about 1-2 nm wide.
- The transistor of a latest-generation processor is 45 nm.
14. “why 100nm, and not 300nm?
“why not 1 to 1000nm?”
• Nanoscience is not just the science of the small, but the science in which
materials with small dimension show new physical phenomena called quantum
effects
• which are size dependent and dramatically different from the properties of
macro-scale materials.
• SO , the reason is the definition itself
15. What is a nanomaterial?
A nanomaterial is an object that has at least one dimension in the
nanometer scale
16. Nanomaterials can be of two types:
“non-intentionally made nanomaterials”
e.g., proteins, viruses, nanoparticles produced during volcanic eruptions, etc.)
“intentionally made” nanomaterials,
which means nanomaterials produced through a defined fabrication process.
nanotechnologies is therefore limited to
“intentionally made nanomaterials”.
17. What makes “Nano” special
First, at the nanometer scale, the properties of matter,
such as energy, change physically explained as quantum
effects
Properties like electrical conductivity, colour, strength and
weight change when the nanoscale level is reached.
The same metal can become a semiconductor or an
insulator at the nanoscale level
18. Size effect
opaque substances become transparent (copper)
inert materials become catalysts (platinum)
stable materials turn combustible (aluminum)
solids turn into liquids at room temperature (gold)
insulators become conductors (silicon).
bulk silver is non-toxic, whereas silver nanoparticles are capable
of killing viruses upon contact
19. What makes “nano” special
Second, they can be fabricated atom-by-atom
with a process called bottom-up
Atom By Atom
20. What makes “nano” special
Finally, nanomaterials have an increased surface-
to-volume ratio compared to bulk materials.
23. “interdisciplinary science”
DNA silicon chips, which are an example of
convergence between semiconductor
science (inorganic chemistry) and biology,
with applications in the medical industry.
26. Nanoscience in Nature: a great starting point
The chemical identity and properties of a substance depend upon
its molecular structure
The interaction of light, water and
other materials with these
nanostructures gives the natural
materials some remarkable
properties which can be
appreciated at the macro scale.
30. Clays
Clays are a type of layered
silicates that are characterized by
a fine 2D crystal structure;
31. Natural colloids
Colloid
• Invisible to the naked eye
• Can’t be separated by filtration
• There is different types of
dispersed material
• Do not settle down
• Usually particle size 1 – 1000
nanometer
• Visible to the naked eye
• Can be separated by filtration
• Dispersed material is usually solid
• Particles can be settled down
• Usually particle size larger than 1
micrometer
Suspension
32. Natural colloids
such as milk and blood
All these materials have the characteristic of
scattering light and often their color (as in the
case of blood and milk) is due to the scattering
of light by the nanoparticles that make them
up.