Carbon Nanotube Applications

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

2. Outline • Introduction • 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. http://www.dbtechno.com Carbon nanotubes • 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 • 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 TPavs 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 • 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 • - 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. (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 • Surface masked by a 400 mesh TEM grid; 20 nm Al/ 10 nm Fe; nanotubes grown for 10 minutes Christine Orme

11. Outline • Introduction • 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 • Diodes and transistors for computing • Capacitors • Data Storage • Field emitters for instrumentation • Flat panel displays • THz oscillators • 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, 872 2009. Rangel et. al., JCP 2009

14. CNT Applications: Structural and Mechanical • High strength composites • Cables, tethers, beams • Multifunctional materials • Functionalize and use as polymer back bone - plastics with enhanced properties like “blow molded steel” • Heat exchangers, radiators, thermal barriers, cryotanks • Radiation shielding • Filter membranes, supports • 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 http://www.gizmodo.com.au/2008/09/carbon_nanotube_manufacturing_breakthrough_could_mean_byebye_steel-2/ 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. Hardness Cu Ag [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: • Nanotube sensors: force, pressure, chemical, Biosensors • Molecular gears, motors, actuators • Batteries, Fuel Cells: H2, Li storage • Nanoscale reactors, ion channels • Biomedical • in vivo real time crew health monitoring • Lab on a chip • Drug delivery • DNA sequencing • Artificial muscles, bone replacement, • 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 • 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 carbonnanotubes in imaging and therapeuticsK. Kostarelos, A. bianco and M. PratoNature 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. 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) 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: Injectablenanorobots 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’ fibrilarnanomaterial. • 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.htm#Single_Walled_Nanotubes_Priceshttp://www.cheaptubes.com/carbon-nanotubes-prices.htm#Single_Walled_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. G5Rebuttal: Carbon-NanotubesApplicattions 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. G1 Review of Carbon-NanotubesApplicattions by EdsonBellido

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. http://www2.polito.it/ricerca/micronanotech/act/immagini/cnt_01.jpg 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. 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. 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 • Chemical Vapor Deposition CVD schematics Precursor gas Substrate Nanotube catalyst • Small scale • Laser Ablation • Arc discharge Modified from ASIN group