1. Carbon Nanotube Applications
J.-C. Charlier
Norma Rangel
Nanotechnology
3/2/2010
Scott Dougherty
University of Texas at Dallas

2. Outline Introduction Application of Carbon Nanotubes
Properties
Fabrication processes
Application of Carbon Nanotubes
Electronic
Unzipping of CNTs
Structural and Mechanical: Composites
Sensors, NEMS, Bio: Microscopy
Biosensors: DNA sequencing
Paper: Promises, facts and challenges for CNTs in imaging and therapeutics
Future Work, conclusions

3. Carbon nanotubes CNT is a tubular form of carbon
CNT is a tubular form of carbon
Length: few nm to microns.
CNT is configurationally equivalent to a two dimensional graphene sheet rolled into a tube.
Can be functionalized

4. Outline Introduction Application of Carbon Nanotubes
Properties
Fabrication processes
Application of Carbon Nanotubes
Electronic
Unzipping of CNTs
Structural and Mechanical: Composites
Sensors, NEMS, Bio: Microscopy
Biosensors: DNA sequencing
Paper: Promises, facts and challenges for CNTs in imaging and therapeutics
Future Work, conclusions

5. Electrical properties
Electrical conductivity six orders of magnitude higher than copper
‘tunable’ bandgap: electronic properties can be tailored through application of external magnetic field, application of mechanical deformation…
Very high current carrying capacity
Excellent field emitter
How nanotechnology works
CNT can be metallic (armchair) or semiconducting, depending on chirality.

6. Mechanical Properties
The strongest and most flexible molecular material because of C-C covalent bonding and seamless hexagonal network architecture
Young’s modulus of over 1 TPa vs 70 GPa for Aluminum, 700 GPA for C-fiber
Maximum strain ~10% much higher than any material
Thermal conductivity ~ 3000 W/mK in the axial direction with small values in the radial direction
Wikipedia

7. Outline Introduction Application of Carbon Nanotubes
Properties
Fabrication processes
Application of Carbon Nanotubes
Electronic
Unzipping of CNTs
Structural and Mechanical: Composites
Sensors, NEMS, Bio: Microscopy
Biosensors: DNA sequencing
Paper: Promises, facts and challenges for CNTs in imaging and therapeutics
Future Work, conclusions

8. Fabrication of CNTs Chemical Vapor Deposition (CVD)
- Patterned growth
Hydrocarbon feedstock
Growth needs catalyst (transition metal)
- Numerous parameters
influence CNT growth
Chemical Vapor Deposition (CVD)
DC arc discharge (Rice)
Laser ablation (NEC, Japan)
- SWNT, high purity, purification methods
[YK Choi, 2007]

9. SWCNTs on Patterned Surfaces
Surface masked by a 400 mesh TEM grid
Methane, 900° C, 10 nm Al/1.0 nm Fe/0.2 nm Mo

10. Surface masked by a 400 mesh TEM grid; 20 nm Al/ 10 nm Fe; nanotubes grown for 10 minutes
(a) “Farms” of carbon nanotubes and (b) a closeup of one farm. Livermore is exploring the potential of such nanotube arrays for detection applications.
Grown using ethylene at 750o C
Christine Orme

11. Outline Introduction Application of Carbon Nanotubes
Properties
Fabrication processes
Application of Carbon Nanotubes
Electronic
Unzipping of CNTs and fibers
Structural and Mechanical: Composites
Sensors, NEMS, Bio: Microscopy
Biosensors: DNA sequencing
Paper: Promises, facts and challenges for CNTs in imaging and therapeutics
Future Work, conclusions

12. CNT Applications: Electronics
CNT quantum wire interconnects
Field emitters for instrumentation
Diodes and transistors for computing
Flat panel displays
Capacitors
THz oscillators
Data Storage
• Control of diameter, chirality
• Doping, contacts
• Novel architectures (not CMOS based!)
• Development of inexpensive manufacturing processes
Challenges
AMES Research center, NASA

13. Mechanism of carbon-nanotubes unzipping into graphene ribbons
(a-f) Gradual unzipping of a (5,5) CNT. Pairs of oxygen atoms are added sequentially. The edges of the unopened (5,5) CNT are passivated with hydrogen atoms and the optimized structure (right) opens only on the internal edge.
D. V. Kosynkin, et. al., Nature London 458,
Rangel et. al., JCP 2009

14. CNT Applications: Structural and Mechanical
High strength composites
Heat exchangers, radiators, thermal barriers, cryotanks
Cables, tethers, beams
Radiation shielding
Multifunctional materials
Filter membranes, supports
Functionalize and use as polymer back bone
- plastics with enhanced properties like “blow molded steel”
Body armor, space suits
- Control of properties, characterization
- Dispersion of CNT homogeneously in host materials
- Large scale production
- Application development
Challenges
AMES Research center, NASA

15. Production of sheets of carbon nanotube “textile”
Production up to 7 meters per minute
Transparent and stronger than a sheet of steel
CSIRO and the University of Texas at Dallas

16. Dispersal of CNTs in Metal Matrix
“One of the major obstacles to the effective use of carbon nanotubes as reinforcements in metal matrix composites is their agglomeration and poor distribution/dispersion in the metallic matrix.” – Morsi & Esawi, 2007
Ball Milling
Most popular by far
Various times/rates
Pestle and Mortar
More Complex Processes
“Molecular Level Process”
Crucible-based process
Dpowd = 70 μm (approx)
DCNT = 40 nm (approx)
Human hair (D~50 μm)
9cm

17. Ag Cu Hardness Resistivity
[Feng et al, Mater. Cha. Eng, 2005]
Resistivity
[Deng et al, Mater. Sci. Eng, 2007]
[Feng et al, Mater. Cha. Eng, 2005]
[Feng et al, Mater. Cha. Eng, 2005]
Agglomeration of CNTs in a re-pressed composite containing 12% vol. CNT

18. CNT Applications: Sensors, Microscopy
CNT based microscopy:
Nanoscale reactors, ion channels
Nanotube sensors: force, pressure, chemical, Biosensors
Biomedical
in vivo real time crew health monitoring
Lab on a chip
Molecular gears, motors, actuators
Drug delivery
DNA sequencing
Artificial muscles, bone replacement,
Batteries, Fuel Cells: H2, Li storage
bionic eye, ear, human organs
• Controlled growth
• Functionalization with
probe molecules, robustness
• Integration, signal processing
• Fabrication techniques
Challenges

19. CNT Applications: Microscopy
Conventional silicon or tungsten tips wear out quickly.
CNT tip is robust, offers amazing resolution.
Small diameter – maximum resolution
Excellent chemical and mechanical robustness
High aspect ratio

20. CNT as Functional AFM tips
Molecular-recognition AFM probe tips:
Certain bimolecular is attached to the CNT tip
This tip is used to study the chemical forces between molecules – Chemical force microscopy
Institute of Optics, University of Rochester

21. CNT Applications: Biosensors
sensors for cancer diagnostics
Identified probe molecule that will serve as signature of leukemia cells, to be attached to CNT
Mechanism: Current flow due to hybridization will be through CNT electrode to an IC chip.
Prototype biosensors catheter development
• High specificity
• Direct, fast response
• High sensitivity
• Single molecule and cell signal capture and detection
Challenges

22. CNT Biological applications: DNA sequencing
Nanotube fits into the major grove of the DNA strand
Apply bias voltage across CNT, different DNA base-pairs give rise to different current signals
With multiple CNT, it is possible to do parallel fast DNA sequencing
Top view and side view of the
assembled CNT-DNA system
Institute of Optics, University of Rochester

23. Outline Introduction Application of Carbon Nanotubes
Properties
Fabrication processes
Application of Carbon Nanotubes
Electronic
Unzipping of CNTs
Structural and Mechanical: Composites
Sensors, NEMS, Bio: Microscopy
Biosensors: DNA sequencing
Paper: Promises, facts and challenges for CNTs in imaging and therapeutics
Future Work, conclusions

24. Promises, facts and challenges for carbon nanotubes in imaging and therapeutics K. Kostarelos, A. bianco and M. Prato Nature nanotechnology | VOL 4 | OCTOBER 2009 |
Why CNTs?
They can be easily internalized by cells and therefore can act as delivery vehicles for a variety of molecules relevant to therapy and diagnosis.
As produced CNTs are insoluble in most organic or aqueous solvents, therefore for biological applications the surface should be modified.
Toxicity effects are under debate

25. Advantages of CNTs over nanoparticles:
the degree of aggregation and the individualization of nanotube materials in the biological milieu (blood, intraperitoneal, interstitial fluids, and so on) have an important role in their pharmacological performance.
Physical properties of CNTs allow efficient electromagnetic stimulation and detection.
Advantages of CNTs over nanoparticles:
Larger inner volumes – can be filled with chemical or biological species.
Open mouths of nanotubes make the inner surface accessible and can be modified.

26. Types of carbon nanotube studied in vivo for imaging and therapy.
All in vivo studies using CNT so far have used one of these types:
Pristine CNTs
Coated CNTs (non-covalent surface modifcation)
a, Pristine carbon nanotubes (CNTs) are those without any surface
modification. b, Lipid‑coated nanotubes (primarily single‑walled nanotubes) with or without PEGylated lipids and other versions of further modified lipid
molecules. c, Copolymer or surfactant‑coated nanotubes (primarily single‑walled nanotubes). PEO is polyethylene oxide; PPO is polypropylene oxide.
d, Single‑stranded DNA (ssDNA)‑coated nanotubes (primarily single‑walled nanotubes). e,f, Chemically functionalized nanotubes (both single‑walled and
multiwalled nanotubes) by 1,3 dipolar cycloaddition (e) and by acid oxidation (f).
Functionalized CNTs (covalent surface modifcation)

27. Preclinical in vivo studies using carbon nanotubes
The majority of preclinical models have focused on oncology

29. CNTs toxicity in biomedicine
Focused in pristine CNTs, administrated by pulmonary routes.
Material, doses and administration are not relevant to medical applications.
Evidence of prolonged accumulation of long, rigid pristine CNTS associated with Cancer risks.

30. Toxicity studies of CNTs developed for medical imaging and therapy

32. CNTs in Medicine Q&A Are carbon nanotubes really useful in medicine?
Proof-of-principle studies indicate that carbon nanotubes may help treat various diseases (cancer, AIDS, malaria, metabolic diseases), but only one study so far has reported a therapeutic outcome (prolonged survival) in a preclinical human-tumour model.
Challenges:
Nanotubes may not treat disease more effectively than established technologies.
The risk-to-benefit ratio offered by nanotube-based therapeutics and diagnostics may weigh towards the risk.
Opportunities:
The possible contributions of nanotubes in medicine are almost unlimited and wide-ranging, from advanced delivery systems, electrodes and biosensors to probes for diagnostics and treatment- monitoring devices.
Can carbon nanotubes help cure cancer?
It is too early to determine because only early-stage preclinical studies are available and at present there are no clinical studies underway.

33. CNTs in Medicine Q&A
Can carbon nanotubes act as ‘nanorobots’ in the blood stream?
A: Injectable nanorobots have not yet been developed, and active navigation of nanoparticles in the blood stream has not been achieved. Therefore, nanotubes can neither act as nanorobots nor be navigated in the blood stream.
Challenges:
Nanotubes as components of nanorobots and other nanomachines that may accumulate and intoxicate the body.
Opportunities:
Carbon nanotubes can act as components of nanofabricated machinery and offer tremendous capabilities — for example in wireless communication and monitoring between the patient and the clinician.

34. CNTs in Medicine Q&A
Are carbon nanotubes biocompatible and what does that mean?
The term ‘biocompatibility’ implies the ability to interact with the biological milieu without adverse reactions.
Chemically functionalized nanotubes have been shown by many groups to be more biocompatible (no immune or acute inflammatory responses) than pristine nanotubes.
Challenges:
Some types of carbon nanotubes or their impurities may accumulate in the body, leading to deposits that may cause unwanted side effects in the long-term.
Opportunities:
New carbon nanotube materials and strategies to make them biocompatible are actively pursued.

35. CNTs for imaging and therapy Q&A
Are carbon nanotubes toxic?
Toxicity depends strongly on the type of nanotube, the dose, the route of administration and the tissue that is most affected.
Pristine nanotubes have been shown to activate various mechanisms associated with toxicity, however these effects are shown to be remarkably reduced when properly functionalized with chemical groups.
So far, no in vivo study using the types of nanotubes developed for medical purposes has reported adverse effects.
Challenges:
The structural similarity and association between carbon nanotubes and the carcinogenic asbestos fibres
Opportunities:
Systematic toxicological studies of carbon nanotubes to make them the ‘standard’ fibrilar nanomaterial.
Need to determine the extent of toxicological risks from using nanotubes, their doses, types and route of administration.

36. http://www. cheaptubes. com/carbon-nanotubes-prices

37. Future Work Already in product: CNT tipped AFM
Big hit: CNT field effect transistors based nano electronics.
Futuristic: CNT based OLED, artificial muscles
Comparison with well stablished alternatives
Challenges
Improve dispersion of carbon nanotubes in matrices
Improve bonding to matrix
Manufacture: Important parameters are hard to control.
Large quantity fabrication process still missing.
Manipulation of nanotubes.

38. Thanks!
Questions?

39. G5 Rebuttal: Carbon-Nanotubes Applicattions
Norma L. Rangel

40. Norma Rangel – Rebuttal
The overall presentation was good. However, from my point of view, it would have been better if instead of presenting that large variety of applications, the presentation have focused on maybe one or two and discuss more about the experimental details such as functionalization process the change in properties after functionalization and the physics behind each process.
I understand this concern, however, the topic was “CNTs” which made it to wide and broad, therefore I tried to present as much as information as I could.
Nevertheless no application was analyzed carefully enough, I mean the methodology and results were not analyzed in detail. The basic working principle used in the applications was not illustrated.
The purpose of my presentation was to give an overview to the audience (mostly undergraduate students) some insights about CNTs basics and applications, which included a fair amount of information from several papers. I understande the reviewer’s concern but I think this could be solve if the audience were more uniform, that is, with the same background and level, also more technical lectures about for example specific fabrication process.
The challenges shown in the last slide were general problems currently faced to make CNTs applications commercially available. The presenter didn’t make any suggestion on how to solve those problems.
Right, my personal opinion about CNTs was not shown in the presentation, I would rather use other materials such as graphene to replace CNTs.

41. On the nanotube textile slide, how are nanotubes separated into the rope of nanotubes? More details on the initial process to grabbing the first few threads of NWs may help.
This is an interesting question, but unfortunately I don’t know the answer and I check my references and is not mentioned anywhere, we would need to contact the authors in order to get this information.
Is the “preclinical human-tumor model” on the slide 32 a computer model simulation or a biological experimental model?
Experimental, a tumor is grown in a laboratory.
What makes CNTs good candidate over other materials/structures for a biomedical device?
Due to the nanometer size of the nanotube -> can be introduce in the cells.
Tube shape -> useful to place the treatment inside and drug delivery.
Properties -> Strength, stability under harsh conditions. Spectroscopy and fluorescence detection.
Are there any other structures or materials that can also be used for the applications discussed in the presentation?
Nano-particles have shown good performance for cancer treatment and have been already applied in current biomedical technologies.

42. Review of Carbon-Nanotubes Applicattions by Edson BellidoG1
Review of Carbon-Nanotubes Applicattions
by Edson Bellido

43. The presenter explained the synthesis methods currently being used, the most important properties of carbon nanotubes and a vary large variety of applications, focusing principally on the used of CNTs for imaging and therapeutics. She point out the challenges and opportunities of using CNTs in vivo.
The presenter discuss about the importance of the functionalization of CNT to be able to use it in medicine applications since the CNTs by itself are not soluble on water and form bundles that could be toxic and can accumulate in the organs.
The overall presentation was good. However, from my point of view, it would have been better if instead of presenting that large variety of applications, the presentation have focused on maybe one or two and discuss more about the experimental details such as functionalization process the change in properties after functionalization and the physics behind each process.

44. Review of CNTs applications lecture
It was summarized very well the physical properties of CNTs which
makes it an outstanding material.
A very broad range of applications for carbon nanotubes was shown.
Nevertheless no application was analyzed carefully enough,
I mean the methodology and results were not analyzed in detail.
The basic working principle used in the applications was not illustrated.
The challenges shown in the last slide were general problems currently
faced to make CNTs applications commercially available. The presenter
didn’t make any suggestion on how to solve those problems.
Alfredo D. Bobadilla

45. Review: Carbon Nanotube Applications
By Mary Coan

46. Review Overall a GREAT presentation
Carbon Nanotubes have many properties that can not be found in any other material
Have many applictions:
Diodes, Capacitors, Flat panel displays, etc…
Challenges were discussed
Control of diameter
Manufacturing costs
Explained many different applications, processes, mechanisms and challenges
Review

47. Review Discussed typical questions regarding CNTs
Example: CNTs in Medicine (Good?)
Discussed the opportunities and challenges for each question discussed
The toxicity of CNTs was discussed
She did a wonderful job by using many images to describe what she was discussing.
The level of the work presented fits the audience very well.
Review

48. Review Carbon Nanotubes (G5)
Diego A. Gomez-Gualdron

49. CNT properties Outstanding electrical conductivity (six times copper)
Outstanding mechanical properties (tensile strength, yet flexible)
Field emitters (they can increase resolution in spectroscopy)
One-dimensional thermal conductivity
Easy functionalization
Enhanced mass transport through the nanotube

50. Production methods Large scale Small scale Chemical Vapor Deposition
CVD schematics
Precursor gas
Substrate
Nanotube
catalyst
Small scale
Laser Ablation
Arc discharge
Modified from ASIN group

51. Applications Microchips elements of reduced size
Composite materials for extreme conditions
Nanosensors for chemical and medical applications
Drug delivery and cancer treatment

52. Assessment
Electronic applications depending on selective production of pure semiconductor/conductor nanotubes at large scale
Biomedical applications still have to solve citotoxicity issues and treatment effectiveness
Mechanical applications pending on nanotube cost issues

53. Review
A good presentation overall. A wide range of applications were shown. Good assessment of status and challenges for each application. Good fluency despite the recurrence of filler words and mumbling during slide transitions. The speaker was confident during the presentation, although not so much during questions. The figures/text balance on the slides could improve
It would have been nice to stress what particular property of the nanotube is being taken advantage of for each specific application (why is the nanotube used for that specific application and not another material)

54. Review for G5
Jung Hwan Woo
Jung Hwan Woo

55. Questions
On the nanotube textile slide, how are nanotubes separated into the rope of nanotubes? More details on the initial process to grabbing the first few threads of NWs may help.
Is the “preclinical human-tumor model” on the slide 32 a computer model simulation or a biological experimental model?
What makes CNTs good candidate over other materials/structures for a biomedical device?
Are there any other structures or materials that can also be used for the applications discussed in the presentation?
Jung Hwan Woo