Transcript Discrete Carbon Nanoparticles *The Fullerenes

Neat and Discrete
Carbon Nanoparticles
Fullerenes and Nanotubes
Buckyball
What are some possible uses for a buckyball?
• molecular ball bearings
• drug delivery vehicles
• semiconductors/transistors
The commercial applications of buckyballs are
novel yet immature in their applications.
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Fullerenes
However, the buckyball discovery has led to
research on a new class of materials called
fullerenes, or buckminsterfullerenes.
Fullerenes are materials with:
• a three dimensional network of carbon atoms,
• each atom is connected to exactly three
neighbors, and
• each atom is bonded by two single bonds and
one double bond (e.g., C82).
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Fullerenes
Why is diamond not a fullerene?
Why is graphite not a fullerene?
Are fullerenes a new allotropic form of carbon?
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Fullerenes
What other questions can we ask
about fullerenes?
How about: “Can anything be put inside of it?”
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Fullerenes
Would the following fit inside of a buckyball?
An atom of nitrogen
d = ~120 pm
Definitely
A molecule of sulfuric acid d = ~700 pm
Not likely
A molecule of hydrogen
d = ~150 pm
Quite possibly
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Fullerenes
Fullerenes with material inside are called cage
compounds, or endohedral compounds.
The formulas of endohedral compounds are
shown as M@C60—where M represents the item
inside of the cage.
Examples of known
compounds include:
N@C60 and La@C82
What possible applications might there be
for endohedral buckyballs?
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Fullerenes
Exohedral compounds are those in which a wide
variety of both inorganic and organic groups
added to the exterior of the cage.
These materials offer the most
exciting potential for useful
applications of fullerene materials.
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Fullerenes
Combination endo- and exohedral compounds
have also been synthesized. An interesting example
is:
Gd@C82(OH)n
The gadolinium (Gd) is inside the cage and the
outside is covered with hydroxyl groups.
Gd@C82(OH)n is a possible enhancement material
for magnetic resonance imaging, MRI.
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Fullerenes
Commercial and biological possibilities exist:
Sunscreens
due to photophysical properties
Antibacterials
due to redox and general
chemical reactivity
Superconducting materials
due to physical properties
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Nanoparticles
Are there other carbon nanoparticles?
If a sheet of graphite is rolled into a cylinder, what
is wrong with this structure?
Hint: don’t forget about
corannulene (buckybowls)!
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Nanotubes
Now you have a carbon NANOTUBE!
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Nanotube News
Cylindrical fullerene discovered in 1991
Internal cylinder diameter of 1 to 50 nm
Length of about 100 nm up to several
micrometers and longer
They can be single walled,
called SWNTs, or made up
of multiple layers, called
MWNTs.
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Nanotubes
Nanotubes have
vastly different
properties than
fullerene cages.
For example…
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Nanotube News
… it’s incredibly strong!
Why do you think nanotubes are so strong?
Hint: diamond’s strength is due to…
Because each carbon atom in a
nanotube is covalently bonded
to three others, it has great
tensile strength.
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Nanotubes
Nanotubes are also light weight, have a high
melting point, and can conduct electricity.
What are some possible uses of nanotubes?
nano-wires
nano-test tubes
nano-velcro
nano-ropes
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Nanotubes
Nano-test tubes
Inner diameter ~1.2 nm
Length ~ 2 micrometers
Volume of 10-21 liter — a zeptoliter!!
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Nanoropes
Nano-ropes
Strongest fiber known – 100
times stronger than steel per
gram.
What applications can you imagine for an
unbelievably strong rope or cable made of such
material?
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Far Out Application?
A space elevator-a new transport into
space?
Is it possible?
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Far Out Application?
Some other things to think about:
Environmental advantages
Lightning hazards
Collisions with space junk
Radiation damage to the ribbon
Is there a limit to how large it can be?
How it is initially deployed?
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Nanotech
How do you think
the field of
nanotechnology
may change
your life
— for better or for worse —
over the next
50 years?
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Making Connections
1. Name the three carbon allotropes.
2. Compare and contrast cylindrical and
spherical fullerenes and their unique
characteristics.
3. What are some possible applications of
discrete carbon nanoparticles?
4. What are some possible applications of
extendable nanoparticles?
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Module Flow Chart
Lesson 1.1 What is
Nanoscience?
What is
Nanoscience?
Examine and
Compare size:
macro, micro, submicro (nano)
SI prefixes
Lesson 1.2 What
Makes Nanoscience
so Different?
Lesson 1.3 What
Makes Nanoscience so
Important?
What makes
Nanoscience so
different?
Compare Newtonian
and Quantum
Chemistry Regimes as
they relate to
nanoscale science
Interdisciplinary
science
The development of
new technologies and
instrumentation
applications whose risk
and benefits have yet to
be determined
Lesson 2.2 Extendable
Solids: Reactivity, Catalysis,
Adsorption
The difference between the
energy at the surface atoms
and energy of the interior
atoms results in increased
surface energy at the
nanoscale
Higher surface energy
allowing for increased
reactivity, adsorption and
catalysis at the nanoscale
Lesson 2.3
Extendable Structures:
Melting Point, Color
Conductivity
In Extendable Structures:
Melting point decreases because
surface energy increases
Color changes because electron
orbital changes with decreased
particle size
Electrical conductivity decreases
because electron orbital changes
with decreased particle size
Neat and Discrete Carbon Nanoparticles: Fullerenes and Nanotubes
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Poster Assessment
Students will further
investigate the essential
question that they have
considered throughout the
module: How and why do
the chemical and physical
properties of nanosamples
differ from those of
macrosamples?
Lesson 2.1 Extendable
Solids
As the size of the
sample decreases the
ratio of surface
particles to interior
particles increases in
ionic and metallic
solids
Lesson 3.1
Carbon Chemistry
Unit 3 Lesson 2
Fullerenes and Nanotubes
The molecular geometry is
related to bond number and type
of bond (single, double, and
triple)
The requirement of four bonds
and their alternate resonance
structures is most significant in
the formation of carbon
allotropes
Different allotropes can have
very different physical and
chemical properties
Fullerenes and nanotubes are
a family of carbon allotropes
They can have different
shapes (spherical and
cylindrical), form
endohedral, exohedral,
SWNTs and MWNTs
compounds, and demonstrate
exceptional tensile strength
Possible application
currently being explored
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