1.  UNIVERSITY OF ENGINEERING AND MANAGEMENT,JAIPUR,RAJASTHAN
TOPIC: NANO TUBES
BRANCH ECE
* SOUDIP SINHA ROY .
.

2. LIST OF DISCUSSION
CARBON NANOTUBE BORON
NANOTUBE

3. CARBON NANOTUBES
DAVID MCDERMOTT
JAKE BORRAJO
PHYS43 MODERN PHYSICS, SRJC
SECTION 5756
INSTRUCTOR: DR. YOUNES ATAIIYAN
MODERN PHYSICS PROJECT

4. WHAT ARE CARBON
NANOTUBES.•CARBON NANOTUBES (CNTS) ARE
ALLOTROPES OF CARBON. THESE
CYLINDRICAL CARBON MOLECULES HAVE
INTERESTING PROPERTIES THAT MAKE
THEM POTENTIALLY USEFUL IN MANY
APPLICATIONS IN NANOTECHNOLOGY,
ELECTRONICS, OPTICS AND OTHER FIELDS
OF MATERIALS SCIENCE, AS WELL AS
POTENTIAL USES IN ARCHITECTURAL FIELDS.
THEY EXHIBIT EXTRAORDINARY STRENGTH
AND UNIQUE ELECTRICAL PROPERTIES, AND
ARE EFFICIENT CONDUCTORS OF HEAT.
THEIR FINAL USAGE, HOWEVER, MAY BE
LIMITED BY THEIR POTENTIAL TOXICITY.

5. HOW CNTS ARE MADE
• ARC DISCHARGE
• CNTS CAN BE FOUND IN THE CARBON SOOT OF
GRAPHITE ELECTRODES DURING AN ARC DISCHARGE
INVOLVING HIGH CURRENT. THIS PROCESS YIELDS CNTS
WITH LENGTHS UP TO 50 MICRONS.
• LASER ABLATION
• IN THE LASER ABLATION PROCESS, A PULSED LASER
VAPORIZES A GRAPHITE TARGET IN A HIGH-
TEMPERATURE REACTOR WHILE AN INERT GAS IS
INSERTED INTO THE REACTOR. NANOTUBES DEVELOP ON
THE COOLER SURFACES OF THE REACTOR AS THE
VAPORIZED CARBON CONDENSES.
• OTHER METHODS WHERE CNTS ARE CREATED:
- CHEMICAL VAPOR DECOMPOSITION
- NATURAL, INCIDENTAL, AND CONTROLLED FLAME ENVIRONMENTS

7. PROPERTIES
• STRENGTH
• ELECTRICAL
• THERMAL
• DEFECTS
• ONE-DIMENSIONAL TRANSPORT
• TOXICITY

8. STRENGTH PROPERTIES
• CARBON NANOTUBES HAVE THE STRONGEST TENSILE
STRENGTH OF ANY MATERIAL KNOWN.
• IT ALSO HAS THE HIGHEST MODULUS OF ELASTICITY.
Material
Young's
Modulus (TPa)
Tensile
Strength
(GPa)
Elongation at
Break (%)
SWNT
~1 (from 1 to
5)
13-53E 16
Armchair
SWNT
0.94T 126.2T 23.1
Zigzag SWNT 0.94T 94.5T 15.6-17.5
Chiral SWNT 0.92
MWNT 0.8-0.9E 150
Stainless
Steel
~0.2 ~0.65-1 15-50
Kevlar ~0.15 ~3.5 ~2

9. ELECTRICAL PROPERTIES
• IF THE NANOTUBE STRUCTURE IS
ARMCHAIR THEN THE ELECTRICAL
PROPERTIES ARE METALLIC
• IF THE NANOTUBE STRUCTURE IS
CHIRAL THEN THE ELECTRICAL
PROPERTIES CAN BE EITHER
SEMICONDUCTING WITH A VERY
SMALL BAND GAP, OTHERWISE THE
NANOTUBE IS A MODERATE
SEMICONDUCTOR
• IN THEORY, 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

10. THERMAL PROPERTIES
• ALL NANOTUBES ARE EXPECTED TO BE VERY GOOD THERMAL
CONDUCTORS ALONG THE TUBE, BUT GOOD INSULATORS
LATERALLY TO THE TUBE AXIS.
• IT IS PREDICTED THAT CARBON NANOTUBES WILL BE ABLE TO
TRANSMIT UP TO 6000 WATTS PER METER PER KELVIN AT ROOM
TEMPERATURE; COMPARE THIS TO COPPER, A METAL WELL-
KNOWN FOR ITS GOOD THERMAL CONDUCTIVITY, WHICH
TRANSMITS 385 WATTS PER METER PER K.
• THE TEMPERATURE STABILITY OF CARBON NANOTUBES IS
ESTIMATED TO BE UP TO 2800OC IN VACUUM AND ABOUT 750OC
IN AIR.

11. DEFECTS
• DEFECTS CAN OCCUR IN THE FORM OF ATOMIC
VACANCIES. HIGH LEVELS OF SUCH DEFECTS CAN
LOWER THE TENSILE STRENGTH BY UP TO 85%.
• BECAUSE OF THE VERY SMALL STRUCTURE OF
CNTS, THE TENSILE STRENGTH OF THE TUBE IS
DEPENDENT ON ITS WEAKEST SEGMENT IN A
SIMILAR MANNER TO A CHAIN, WHERE THE
STRENGTH OF THE WEAKEST LINK BECOMES THE
MAXIMUM STRENGTH OF THE CHAIN.

12. ONE-DIMENSIONAL TRANSPORT
• DUE TO THEIR NANOSCALE DIMENSIONS, ELECTRON
TRANSPORT IN CARBON NANOTUBES WILL TAKE
PLACE THROUGH QUANTUM EFFECTS AND WILL
ONLY PROPAGATE ALONG THE AXIS OF THE TUBE.
BECAUSE OF THIS SPECIAL TRANSPORT PROPERTY,
CARBON NANOTUBES ARE FREQUENTLY REFERRED
TO AS “ONE-DIMENSIONAL.”

13. APPLICATIONS
• NANOTUBES HOLD THE PROMISE OF CREATING NOVEL
DEVICES, SUCH AS CARBON-BASED SINGLE-ELECTRON
TRANSISTORS, THAT SIGNIFICANTLY SMALLER THAN
CONVENTIONAL TRANSISTORS.

14. NANOTUBES’ EXCELLENT STRENGTH TO WEIGHT RATIO
CREATES THE POTENTIAL
TO BUILD AN ELEVATOR TO
SPACE.

15. QUANTUM COMPUTING
• NANOTUBES AND OTHER FULLERENES CAN BE FILLED WITH
MOLECULES THAT HAVE EITHER AN ELECTRONIC OR
STRUCTURAL PROPERTY WHICH CAN BE USED TO REPRESENT
THE QUANTUM BIT (QUBIT) OF INFORMATION, AND WHICH
CAN BE ASSOCIATED WITH OTHER ADJACENT QUBITS.

16. HEALTH HAZARDS
• ACCORDING TO SCIENTISTS AT THE NATIONAL INSTITUTE OF
STANDARDS AND TECHNOLOGY, CARBON NANOTUBES
SHORTER THAN ABOUT 200 NANOMETERS READILY ENTER
INTO HUMAN LUNG CELLS SIMILAR TO THE WAY ASBESTOS
DOES, AND MAY POSE AN INCREASED RISK TO HEALTH.
• CARBON NANOTUBES ALONG WITH THE MAJORITY OF
NANOTECHNOLOGY, ARE AN UNEXPLORED MATTER, AND
MANY OF THE POSSIBLE HEALTH HAZARDS ARE STILL
UNKNOWN.

17. BORON NANOTUBE

18. Scientists used to think know everything about this element, and since it was not in great
demand in industry boron was out of the focus of attention.
But in recent decades, boron and its compounds has found application in different
industries such as atomic, rocket-building, metal processing, chemical and many others.
Boron atoms are capable of forming both ion and covalent bonds. They can make
chains, frames, nets etc. Still, we do not know much about this element.
Boron has found application in many fields of modern technology.
 small addition of boron to steel (0,0005…0,005 %) increase its hardness!
 Boron better than any other element removes gases from copper that improve its
properties.
Saturation of metals with boron forms hard borids!
«We need to know much to understand how
little we know»

19. THERE IS NO CONSENSUS ABOUT HOW MANY BORON
MODIFICATIONS EXIST.
• RESEARCHERS (BORIS
YAKOBSON) ANTICIPATED THE
EXISTENCE OF A FULLERENE
CONSISTING OF 80 BORON
ATOMS.
• BORON NANOTUBES WERE
SYNTHESISED RECENTLY AND
THEIR PROPERTIES AND NATURE
HAVE NOT BEEN FULLY
REVEALED.
__________________________________________________________________________________________________

20. ONE OF THE CONFIGURATIONS OF BORON –
HEXAGONAL BORON
FIG. 1.BORON STRUCTURE.
• TABLE 1. MAIN PROPERTIES OF QUASI-
PLANAR HEXAGONAL BORON.
The number of atoms в
EEC
Atom charge Ionazation potential, eV
64 0
7.31
80 0
7.25
88 0
7.95
96 0
8.08
108 0
8.13

21. BY ANALOGY WITH CARBON NANOTUBES WE
ASSUMED THAT BORON NANOTUBES CAN BE
CONSTRUCTED BY ROLLING OF HEXAGONAL
QUASI-PLANAR BORON
DUE TO THREE-CENTER BONDING
BORON NANOTUBES ARE MAINLY OF
TRIANGULAR AND HEXAGONAL TYPES.

22. BORON NANO TUBES WITH DEFECTS
BORON NANOTUBE WITH SUBSTITUTION DEFECTS (EITHER NEUTRAL CARBON
ATOM (С), OR POSITIVELY (С+) AND NEGATIVELY (С–) CHARGED CARBON IONS)

23. SORPTION PROPERTIES OF BORON
NANOTUBES
• IT IS KNOWN THAT BORON NANOTUBES HAVE
UNIQUE SOPTION PROPERTIES. MUCH
RESEARCH INTO THE MECHANISM OF ATOM
AND MOLECULAR ADSORPTION ON THEIR
SURFACE HAS BEEN CARRIED OUT.
• THE STUDY OF THE SURFACE STRUCTURE
HYDROGENATION IS PROMISING FOR ITS
APPLICATION AS A STORAGE FOR
MOLECULAR HYDROGEN.
• THE SEARCH FOR STRUCTURES WITH WELL-
DEVELOPED SURFACES CAPABLE OF
ADSORBING GASES (INCLUDING HYDROGEN)
REMAINS IN THE FOCUS OF ATTENTION. IN
THIS RESPECT RESEARCH OF SORPTION
PROPERTIES OF BORON NANOTUBES IS
IMPORTANT.
______________________________________________

24. REFERENCES
• HTTP://WWW.NEWS-MEDICAL.NET/NEWS/22799.ASPX
• CHAE, H.G.; KUMAR, S. (2006). "RIGID ROD POLYMERIC FIBERS".
JOURNAL OF APPLIED POLYMER SCIENCE 100:791-802: 791.
DOI:10.1002/APP.22680.
• HONG, SEUNGHUN; SUNG MYUNG (2007). "NANOTUBE
ELECTRONICS: A FLEXIBLE APPROACH TO MOBILITY". NATURE
NANOTECHNOLOGY 2: 207–208. DOI:10.1038/NNANO.2007.89
• MEO, S.B.; ANDREWS R. (2001). "CARBON NANOTUBES: SYNTHESIS,
PROPERTIES, AND APPLICATIONS". CRIT. REV. SOLID STATE MATER.
SCI. 26(3):145-249: 145. DOI:10.1080/20014091104189.
• KOLOSNJAJ J, SZWARC H, MOUSSA F (2007). "TOXICITY STUDIES OF
CARBON NANOTUBES". ADV EXP MED BIOL. 620: 181–204. PMID
18217344
• EBBESEN, T. W.; AJAYAN, P. M. (1992). "LARGE-SCALE SYNTHESIS
OF CARBON NANOTUBES". NATURE 358: 220–222.
DOI:10.1038/358220A0