Fullerenes and Nanotubes

Question 1

what are fullerene structures?

Answer 1

an allotrope of carbon whose molecule consists of carbon atoms connected by single or double bonds so as to form a closed packed or partially closed mesh, with fused rings of 5 to 7 atoms

Question 2

What shape may fullerenes take?

Answer 2

may be a hollow sphere, ellipsoid or tube.

Question 3

How are fullerenes with close packed meshes denoted?

Answer 3

with empirical formula Cn where n is the number of atoms

Question 4

What is the most famous fullerene?

Answer 4

C60 _ buckminsterfullerene or Buckyballs

Question 5

What are cylindrical fullerenes called?

Answer 5

Carbon nanotubes of Buckytubes

Question 6

what is the smallest fullerene structure?

Answer 6

C20 - high strain so energetically unfavourable

Question 7

what is sp2 hybridization?

Answer 7

a carbon atom is sp2 hybridized when bonding takes place between 1s orbital with 2p orbitals. Forms 2 single bond and 1 double bond between 3 atoms.
- Hybrid orbitals placed in a triangular arrangement with 120degree bond angles

Question 8

What is the diameter of carbon nanotubes?

Answer 8

0.4-200nm

Question 9

What is the length of carbon nanotubes?

Answer 9

microns to millimetres

Question 10

How are they made?

Answer 10

Sheets of graphene can be rolled to produce a single walled nanotube, or by extending fullerenes around waist

Question 11

What are the 2 different types?

Answer 11

Single or multiwalled(20-50 layers) carbon nanotubes

Question 12

What is a carbon nanotube?

Answer 12

Hollow tube made up of carbon of the nanoscale diameter

Question 13

Chirality and electronic properties are different in 3 different types of nanotube?

Answer 13

Armchair, zigzag, chiral

Question 14

Multiwalled Carbon nanotube properties?

Answer 14

*E = 0.3 to 1.5 TPa
*stress f = 2 – 63 GPa
*Depends on defects
*Sword-in-sheath failure

Question 15

properties of single walled carbon nanotubes?

Answer 15

*E = 0.03 – 1.5 TPa
(~ 0.8 TPa probably for a good tube)
*sf = ~ 20 GPa
*Depends on defects
*Possibly depends on chirality and diameter

Question 16

General properties of carbon nanotubes?

Answer 16

• very stiff, as stiff as diamond
• gravitational weight very low
• density is very low
• stronger than steel
• high thermal capacity
• good heat and electrical conductor
• chemically neutral
• high youngs modulus

Question 17

nanotube morphology?

Answer 17

High aspect ratio (1000 +)
* High surface area (1315 m2g−1 for SWCNT)

Question 18

uses in electrodes?

Answer 18

– Batteries
– Fuel cells
– Sensors

Question 19

uses in composites?

Answer 19

Matrix modifier
Anti-static
EMI shielding
– Structural reinforcement

Question 20

uses in energy storage?

Answer 20

Super-capacitors
– H2 storage?

Question 21

uses in electronics?

Answer 21

Heat management
– Vias
– Field emission
– Transistors
– Transparent electrodes

Question 22

Issues with carbon nanotubes?

Answer 22

• Production on large scale
• Control
• Scale-up before/after commercialisation of applications
• Cost
• Toxicity
• Manipulation
• Development needs lots of equipment and money

Question 23

what bio systems can CNT’s be used in?

Answer 23

hypothermia agent, drug delivery and transfection, processing, sensors and interface, scaffolds- stuctural and model surfaces

Question 24

Describe the structure of carbon nanotube and how it is related to C60?

Answer 24

The bonding in carbon nanotubes is sp², with each atom joined to three
neighbours, as in graphite. The tubes can therefore be considered as
rolled-up graphene sheets or as extending fullerenes around waist.
There are three distinct ways in which a graphene sheet can be rolled
into a tube, armchair, zig-zag and chiral.