Carbon nanotubes

1. Carbon Nanotubes
and
It’s Applications
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9/2/2019 1Carbon Nanotubes and Its Applications

2. 9/2/2019 2Carbon Nanotubes and Its Applications
İçerik
•Carbon forms: Carbon nanotubes (CNT)
•Atomic Structures of CNTs
•Physical properties of CNTs
•Kinds of CNTs
•How to make CNTs
•Applications

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Carbon, C: Principle element of the life!
Carbon has different forms in nature which is also basic element of organic
elements and life! It is in DNA, proteins, fats, and carbohydrates. It makes up
approximately 20% of the human body.
2D, Graphene 3D, Graphite 3D, Diamond
sp2 hybridization,
hexagonal structure
Weak Van der Waals bonds
the graphene layers together
sp3 hybridization
Band structure determines the physical properties of materials.

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Nanotube Structure
Nanotube
Fullerene, C60
Graphite

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Atomic Structures of Nanotube
• Take two lines along tube axis: Blue lines
•Take a point on blue line that intersects
one of C atom (Point A)
•Draw the Armchair that across the
hexagone in two half (yellow line)
•Take another intersection point on second
axis (Point B)
•Connect A and B (Red Arrow): Chirality
(Twist) axis
•Ll
•Ф is the angle between Armchair and
Chiral vector.

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Atomic Structures of Nanotube
(a) If Ф= 0, Armchair nanotube
(b) If Ф= 30°, zigzag nanotube
(c) If 0 < Ф < 30° , Chiral (twisted)
nanotube
Jeroen W. G. et all Nature 391, (1998)
What is the importance of Ф ???

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Chirality and Physical Properties of CNTs
P. L. McEuen et all, 2002
Metallic CNTs:
Ф= 0 (Armchair) and conduction and
valance band overlaps.
Semiconducting CNTs:
Ф ≠ 0 (Chiral) and there is an energy
gap between conduction and valance
band.
Potential electronic
applications!!!

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Number of Walls for CNTs
Single wall CNT
Multi wall CNT
Average diameter of single wall CNT:
1.2 nm
Length to diameter ratio:
>>1
Spacing between multi wall CNT:
~3.3 Å

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How to make CNTs?
1. Arc Discharge method (Discovery?)
2. Laser Ablation
3. Chemical Vapor Deposition (CVD)
Discovery of Carbon Nanotubes
CNTs were discovered by Sumio Iijima, 1991 using arc-discharge
method.

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Arc-Discharge Method
•Two graphite rod is placed very close proximity of each other, >>1mm
•Drive 50-100A current in vacuum chamber, in He atmosphere
•For single wall CNT production, Ni or Co added in anode as seed in reaction.

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Laser Ablation Method
Smalley et all 1995, Rice University
•Pulsed laser evaporate the graphite in
a hot furnace.
•Evaporated C atoms are energized by
Ar atoms and condensed on cooled
collector.
•For single wall CNT production Ni, Co
is added into graphite as a catalyst.
•Yields single wall CNTs with 70%
efficiency in determined diameter and
length.
•Expensive method.

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Chemical Vapor Deposition Method
•Co, Fe, Ni are evaporated on Si or SiO2
substrate which is placed on hot plate.
•High frequency AC voltage is applied
between graphite poles.
•C2H2, CH4, C2H4, C2H6, CO are used as C
source.
•C atoms in plasma are condensed on
substrate.
•The catalyst has a strong effect on the
nanotube diameter, growth rate, wall
thickness, morphology and microstructure.

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CNTs

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Physical properties of CNTs
Strength
Thermal
Transport
•Strongest and stiffest materials yet discovered. Tensile strength of 63 GPa.
•The ability to endure weight of 6300 kg on a cable with cross-section of 1 mm2
•Specific strength of up to 48,000 kN·m/kg is the best of known materials,
compared to high-carbon steel's 154 kN·m/kg
•Low density of 1.3-1.4 g/cm3 (Density of copper is 8.92 g/cm3 )
•Transmit up to 6000 watts per meter per Kelvin at room temperature
•Copper transmits 385 watts per meter per K
•Transports electrons in one dimension (1D) along the axis.

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Physical properties of CNTs
Electrical
Kinetic
•Metallic nanotubes can carry an electrical current density of 4×109 A/cm2
which is more than 1,000 times greater than metals such as copper.
•Multi-walled nanotubes, exhibit a striking telescoping property whereby an
inner nanotube core may slide, almost without friction, within its outer
nanotube shell thus creating an atomically perfect linear or rotational
bearing. This is one of the first true examples of molecular nanotechnology,
the precise positioning of atoms to create useful machines.
So What???
Hong, Seunghun et all., 2007, Nature Nanotechnology

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Applications of CNTs
Scanning Probe Microscope Tip for High Resolution Imaging
CNT is grown on Si cantilever tip or mounted afterwards. These kind of tips were used
for high resolution magnetic imaging after coated with thin layer of Co.
MFM Image of 394 GB/inch2 Hard Disk

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CNT Hall Probe
P. L. McQuen et all, Physics World
•Magnetic field measurement in a way that: high sensitivity and high spatial
resolution!!!
•Better than 5 nm spatial resolution possibility!!!
Magnetic Sensor
Hall Effect in a conductor sheet

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CNT Transistor
P. L. McQuen et all, Nano Letters, 2006
AFM image of a SWNT between two gold electrodes. The NT diameter is 2.6
nm, and its length is 10 µm.
Potential application of high frequency/performance circuit element!

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CNT Resonator
Vera et all, Nature, 2004
SWNT resonator hanging on between Sorce and Drain amd Its resonance
frequency.
Application: Gas Sensor, Force Sensor, Bio Sensor

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Innovations in Daily Life
•Tough & Light devices for sports, automotive, spacecrafts
•Ceramics/metals structural parts production in high strength
•Antistatic applications
•Electromagnetic interference shielding
•In Li Batteries
•How do you that?
•CNTs are placed on fiber-reinforced epoxy resin
or matrix or coated

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Drug Delivery and CNTs
Zhuang Liu et all, Cancer Research, 2008
•Chemically functionalized single-walled carbon nanotubes (SWNT) is used in
vivo applications.
•Drugs are attached the funtionalized SWNT and delivered to the place where
tumor is located.
•Nanotube drug delivery is promising for high treatment efficacy and minimum
side effects for future cancer therapy with low drug doses.

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Quick Blood Test with CNTs
•One-dimensional nanostructures such as nanowires are ideal for diagnosis as
they can be integrated into microfluidic chips that provide a complete sensor
system.
•Blood components stick to the uncoated carbon nanotube in the top panel, but
not to the heparin-coated nanotube depicted in the lower panel.
Image courtesy of
Saravanababu Murugesan
and Robert J. Linhardt

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CNTs and Tissue Engineering
Carbon nanotubes may be an important tissue engineering
material for:
•improved tracking of cells,
•sensing of microenvironments,
•delivering of transfection agents,
•scaffolding for incorporating with the host's body

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Conclusion
•Carbon nanotubes has great diversity of superior physical
properties.
•The mass production is available.
•Many potential application is shown in many basic researches
ans science.
•They have already in our life.
•Many applicaitons, especially in medical area, will be waiting for
the researches.

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Thanks for your attention!
Any comments?