Carbon nanotubes are one of the emerging materials developed in recent two decades. This report summarises the information of carbon nanotubes with their various synthesis techniques to produce CNTs. Different structures have been discussed like single-shell tubes, multi-shell tubes, bundles and cones. Notable state of the art characterization techniques like SEM, TEM, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, EDS, EDX, HRTEM has been also briefly discussed to study their structure- property correlation in this candidate material. Properties such as low dimensability, high surface-to-volume ratio is observed in carbon nanotubes. Unique mechanical, optical, electrical and electrochemical properties for carbon nanotubes are elaborately discussed here. Carbon nanotubes are advanced materials having tubular structure with nanometre diameter and large length/diameter ratio. Other properties such as density, stability is important for CNTs. Finally, prospects for carbon nanotubes are considered for carbon nanotubes.

1. SEMINAR PRESENTATION
CARBON NANOTUBES (CNTs)
Faculty- Dr. Angayar Pavanasam
Presented by:
ARCHIT TIWARI (11211610)
ASTBHUJA (112116014)
NITESH KUMAR SHARMA (112116041)
RISHAB BHARTI (112116046)
SHUBHAM GUPTA (112116051)
SURYAKANT GOND (112116057)

2. CONTENT
• INTRODUCTION
• TYPES OF CARBON NANOTUBES
• STRUCTURE OF NANOTUBES
• SYNTHESIS OF CNTs
• CHARACTERIZATION TECHNIQUES
• PURIFICATION METHODS
• PROPERTIES
• APPLICATION
• CONCLUSION
• REFERENCES

3. INTRODUCTION
• Carbon nanotubes are one of the emerging materials developed in
recent two decades.
• Carbon nanotubes is one of the promising candidate materials for
various applications.
• Carbon nano tubes show unexplored potential application in
domain of science, medicine, energy and chemical industry and
others.
• The history of CNTs arose at Cambridge University, department of
Material science under the leadership of Alan Windle.
• These carbon nanotubes have dimensions in scale of nanometres
with different structures.
• Layer-by-layer deposition of carbon along with other elements
forming functional groups.
• Notable state of the art characterization techniques like
SEM
TEM
Raman Spectroscopy
Fourier Transform Infrared Spectroscopy
EDS, EDX
HRTEM
• Purification techniques like
Oxidation
Annealing and thermal treatment
Ultrasonification
Microfiltration
• Thereafter, the properties and application will be
discussed.

4. STRUCTURE OF NANOTUBES
• Carbon nanotubes possess hexagonal and pentagonal network configuration.
• Consists honey-comb lattice pattern with one dimensional periodic structure
along the tube axis.
• Helical arrangement gives zigzag and arm-chair tubes
• Closed with hemispherical C60 caps with 3-fold and 5- fold symmetry in the
figure.
• Two caps on both side of CNT of 10 A have 12 pentagons in their structure.
• Tubes have larger diameters between 20 A and 70 A
• Concentric shells being added by graphite cylindrical layer growth.
• Carbon nanotubes also influence the filling process i.e. both in-situ and ex-situ
filling methods, which governs the filling yield, size and structure of CNTs.
• Growth depends on composition of catalyst used for the synthesis of the
carbon nanotubes.
• Closed nanotubes tips have less reactivity compare to open end nanotubes.
• Fibres, yarns and unidirectional textile forms the network of thousands carbon
nano tubes (CNT)
• The nanotubes are nearly perfect 1-D conductor.

5. TYPES OF CARBON NANOTUBES
SINGLE-WALL NANOTUBES
• SWCNTs consist of a single cylindrical carbon layer with a
diameter in the range of 0.4-2 nm, depending on the
temperature at which they have been synthesized
• The structure of SWCNTs may be arm chair, zigzag, chiral, or
helical arrangements
• In drug delivery, SWCNTs are known to be more efficient
than MWCNTs.
• This is due to the reason that SWCNTs have ultra-high
surface area and efficient drug-loading capacity.
• Once the functionalized of SWCNT releases the drug into a
specific area, it is gradually excreted from the body via the
biliary pathway and finally in the feces.
• This suggested that SWCNTs are suitable candidates for drug
delivery and a promising nanoplatform for cancer
therapeutics.
MULTI-WALL NANOTUBES
• MWCNTs consist of several coaxial cylinders
• The outer diameter of MWCNTs ranges from
2-100 nm, while the inner diameter is in the
range of 1-3 nm
• MWCNTs structures can be split into two
categories based on their arrangements of
graphite layers: one has a parchment-like
structure which consists of a graphene sheet
rolled up.
Special tube types
(Courtsey: Valentin N Popov, “Carbon nanotubes: properties and
application”, Materials Science and Engineering: R: Reports, Volume 43,
Issue 3, (2004): 61-102)

6. SYNTHESIS OF CNTs
ELECTRIC ARC DISCHARGE
• Traditional method founded by Lijima
• Electric arc vaporizes a hollow graphite anode using a mixture of
transition metal such as Fe, Cu, Ni
• High quality CNTs “pillar like tubes” with diameter ranging from
0.6 to 1.4 nm to 10 nm
• Control of arcing current and inert gas pressure
• Pure hydrogen gas is best gas for obtaining high crystallinity in
MWCNTs
• The parameters are 2000°C-3000°C, 20 V and 50-600 torr
LASER ABLATION
• Known as Pulsed Laser Vaporization (PLV)
• Method vaporizes carbon and deposit it on the surface
• Rice university in 1995 synthesized CNT based on this
technique
• The setup consists of a target carbon composite doped with
catalytic metal, furnace, quartz tube, water cool trap and flow
system
• Laser beam (typically a YAG or CO2 laser) can enter window
and focus on target to vaporize high temperature argon gas
and form SWCNTs.
(Courtesy: T. Guo, P. Nikolaev, A. Thess, D.T. Colbert, R.E. Smalley, Chem.
Phys. Lett. 243 (1995): 49–54)
(Courtesy: T.W. Ebbesen, Production and purification of carbon nanotubes, in:
T.W. Ebbesen (Ed.), in carbon nanotubes: Preparation and Properties, CRC, Boca Raton, FL, 1997 , pp. 139–
162)

7. SYNTHESIS OF CNTs
CHEMICAL VAPOR DEPOSITION
• A method to produce CNTs
• Precursor gases such as benzene, methane, ethanol cause
chemical reactions
• High temperature to cause decomposition reaction on solid
substrate
• CVD is quite flexible, uncomplicated technology to control
and design
• The advantages include availability of abundant raw
material.
FCCVD
• FCCVD is direct spinning methods for CNTs
• Drawing continuous CNT aerogel directly from the gas
phase
• Combining the continuous synthesis and collection of the
CNT fibres
• This suspension-based method is fabricated by spin
coating, spray coating etc.
(Courtesy: N.M. Mubarak, Y. Faridah, Chem. Eng. J. 168 (2011) 461–469)
(Courtesy: O. Rousseau, C. Locard, A. Kane, Y. Roussign_e, S. Farhat, S.M. Ch_erif, Elaboration and magnetic
properties of cobalt-palladium magnetic nanowires encapsulated in carbon nanotubes,
J. Surf. Eng. Mater. Adv. Technol. 07, 2017)

8. CHARACTERIZATION TECHNIQUES
FESEM
• FESEM stands for field emission scanning electronen
microscope (FESEM)
• Technique used for researchers in biology, chemistry and
physics
• To observe small structures on the surface of cells and
material.
• A few examples are organelles and nuclei of cells,
synthetical polymers and coatings of microchips.
HRTEM
• It stands for high resolution transmission microscopy
• Used for study the morphology of the raw and
functionalized of MWCNTs with the carboxyl groups.
• Identifying the nature and the form of carbon
nanomaterials.
• TEM images of CNTs and CNFs clearly distinct, but it
is quite difficult to know the exact number of walls.
(Courtsey: Susan Liao, Guofu Xu, Wei Wang, Fumio Watari, Fuzhai Cui, Seeram Ramakrishna, Casey K. Chan, “Self-assembly of nano-hydroxyapatite on multi-walled carbon nanotubes, Acta
Biomaterialia”, Volume 3, Issue 5, (2007): 669-675.)

9. CHARACTERIZATION TECHNIQUES
EDS/ EDX
• EDS/ EDX is an analytical techniques to analyse elemental
or chemical characterization
• Chemical elements with their evidence.
• It can be used for quantitative and qualitative analysis
• It is used along with WDS to get a elemental X-ray
compositional map of the specimen.
FTIR
• It stands for Fourier Transform Infrared Spectroscopy.
• MWCNTs several peak can be analysed showing
function groups
• FTIR Spectra of MWCNTs-COOH shows peak range
from 2800-3000cm.
• Interaction of the IR radiation with matter and
measures the frequencies of the radiation
(Courtesy: Hadi Karami, Solmaz Papari-Zare, “The thermophysical properties
and the stability of nanofluids containing
carboxyl-functionalized graphene nano-platelets and multi-walled carbon nanotubes”,
International Communications in Heat and Mass Transfer, Volume 108, (2019): 104302.)
(Courtesy: Hadi Karami, “The thermophysical properties and the stability of nanofluids
containing carboxyl-functionalized graphene nano-platelets and multi-walled carbon nanotubes”,
International Communications in Heat and Mass Transfer, Volume 108, (2019): 104302.)

10. CHARACTERIZATION TECHNIQUES
AFM
• It stands for Atomic Force microscopy Technique
• 3-D morphology of carbon nanotubes
• AFM measurements with a conductive tip were
successfully used to measure the electrical transport
properties of carbon nanotubes.
• It is possible to use carbon nanotubes as AFM probes
due to their exceptionally high Young modulus of the
order of 1 GPa as determined from AFM measurements.
RAMAN SPECTROSCOPY
• Raman Spectroscopy is a non-destructive chemical
analysis technique
• Detailed information about chemical structure, phase
and polymorphology, crystallinity and molecular
interactions.
• It is based upon the interaction of light with the
chemical bonds within a material.
(Courtesy: Hadi Karami, Solmaz Papari-Zare, Mehdi Shanbedi, Chew Bee Teng, “The thermophysical properties and the stability of nanofluids containing carboxyl-functionalized graphene nano-platelets and multi-
walled carbon nanotubes”, International Communications in Heat and Mass Transfer, Volume 108, (2019): 104302)

11. PURIFICATION METHODS
• Carbon nanotubes contains large amount of
impurities in different forms.
• The impurities may be present in form of any
particle, raw product or undesired elements.
• These undesired elements are eliminated by
purification techniques used for carbon nanotubes.
• The impurities are removed from the surface or walls
of the carbon nanotubes.
• The few promising techniques include oxidation, acid
treatment, annealing and thermal treatment, micro-
filtration and ultra-sonification.
• After applying these techniques, we can get carbon
nanotubes with improved surface, removal of
unwanted functional groups.
OXIDATION
• Oxidation is a way of the promising way to remove the
impurities.
• Impurities such as oxidizing catalyst. Metal catalyst are
detached from the surface of the CNTs after promoting
the CNTs to elevated temperature, where the oxidation
happens.
• The efficiency and productivity of oxidation method
depends on various factors like exposed environment,
temperature, time metal content, etc.

12. PURIFICATION METHODS
ACID TREATMENT
• Acids like nitric acid (HNO3), hydrochloric acid (HCl) and
sulphuric acid (H2SO4) for treatment
• Generally, hydrochloric acid (HCl) is regarded as refluxing
acid
• When nitric acid (HNO3) is used for treatment, effect on metal
catalyst
• The figure here show the image obtained from acid treatment
when the carbon nanotube is exposed to HCl acidic medium for
purification.
ANNEALING AND THERMAL TREATMENT
• Annealing and thermal treatment is other method when they
are exposed to higher temperatures
• Metal impurities present on the wall of the CNTs are
removed by melting
• The graph here shows the CNT content when annealed at
different temperatures
• It is found that, the hardness is maximum when the
temperature is minimum
(Courtsey: Susan Liao, Guofu Xu, Wei Wang, Fumio Watari, Fuzhai Cui, Seeram Ramakrishna, Casey K. Chan,
“Self-assembly of nano-hydroxyapatite on multi-walled carbon nanotubes, Acta Biomaterialia”, Volume 3, Issue 5, (2007): 669-675.)

13. PURIFICATION METHODS
ULTRASONICATION
• Ultrasonification is a method where the carbon nanotubes
are dispersed in the solution
• The vibration removes the unwanted articles
• Process is highly depend on the reagent, solution and
surfactant
• When the acid is exposed in ultrasonification technique,
the metal particles are solvated
MICRO-FILTRATION
• Micro-filtration is one of the best method
• CNTs are trapped in the filter
• Unwanted metal particles are passed through the filter
• Cross flow filtration is special case of micro-filtration
• PVDF membrane is used
(Courtesy: Doan Dinh Phuong, et. al, “ Effects of carbon nanotube content and annealing temperature on the hardness of CNT reinforced aluminum
nanocomposites processed by the high pressure torsion technique” Journal of Alloys and Compounds, Volume 613, 2014,68-73)

14. PROPERTIES
• CNTs have excellent electronic and mechanical
properties
• These nano tubes have
high young’s modulus
tensile strength.
• CNTs have high stiffness and axial strength due to
carbon -carbon sp2 bonding
• Specific heat and thermal conductivity of the carbon
nano tubes system are determined primarily by
phonons.
• CNTs filled with ferromagnetic materials such as
Fe
Co
Ni exhibits a strong magnetic anisotropy magnetic
coercivity in axis parallel to the alignment of nanotubes.
• SWNT are either
metallic
semiconductor depending on their structural parameters.
• In π- tight binding model within the zone folding scheme,
one third of the nano tubes are metallic are semi
conducting depending on their indices (n, m).
• It is found that 3% stretching of CNT mats resulted in
tensile strength of 4.48MPa and modulus of 67.9 GPa.

15. APPLICATION
• Carbon nanotubes finds widespread application in
sensors
lithium-ion batteries
data storage devices
capacitor-based nano electric devices
fuel cell etc.
• The other application includes
Biological application
purification/filtration
opto-electronic devices
thin film transistor.

16. REFERENCES
[1] Klaus Sattler, “Scanning Tunneling Microscopy of carbon nanotubes and nanocones, Carbon Nanotubes”, Pergamon, (1996):
65-70.
[2] J.-P. Issi, L. Langer, J. Heremans, “Electronic properties of carbon nanotubes: experimental results”, Carbon Nanotubes,
Pergamon, (1996): 121-128.
[3] Hadi Karami, Solmaz Papari-Zare, Mehdi Shanbedi, Chew Bee Teng, “The thermophysical properties and the stability of
nanofluids containing carboxyl-functionalized graphene nano-platelets and multi-walled carbon nanotubes”, International
Communications in Heat and Mass Transfer, Volume 108, (2019): 104302.
[4] Susan Liao, Guofu Xu, Wei Wang, Fumio Watari, Fuzhai Cui, Seeram Ramakrishna, Casey K. Chan, “Self-assembly of nano-
hydroxyapatite on multi-walled carbon nanotubes, Acta Biomaterialia”, Volume 3, Issue 5, (2007): 669-675.
[5] Christofer Hierold, Alain Jungen, Christoph Stampfer, Thomas Helbling, “Nano electromechanical sensors based on carbon
nanotubes”, Sensors and Actuators A: Physical, Volume 136, Issue 1, (2007): 51-61.
[6] J. Derakhshandeh, Y. Abdi, S. Mohajerzadeh, H. Hosseinzadegan, E. Asl. Soleimani, H. Radamson, “Fabrication of 100nm gate
length MOSFET's using a novel carbon nanotube-based nano-lithography”, Materials Science and Engineering: B, Volumes 124–
125, (2005): 354-358.
[7] Anastasiia Mikhalchan, Juan José Vilatela, “A perspective on high-performance CNT fibres for structural composites”, Carbon,
Volume 150, (2019): 191-215.
[8] Yuba Raj Poudel, Wenzhi Li, “Synthesis, properties, and applications of carbon nanotubes filled with foreign materials: a
review”, Materials Today Physics, Volume 7, (2018): 7-34.

17. THANK YOU