Carbon Nano-tubes & Graphene (WJEC GCSE Chemistry)

Carbon Nano-tubes & Graphene

Graphene

• Graphene consists of a single layer of graphite which is a sheet of carbon atoms covalently bonded forming a continuous hexagonal layer

• It is essentially a 2D molecule since it is only one atom thick

• It has very unusual properties make it useful in fabricating composite materials and in electronics

Diagram to show the structure and bonding in graphene

Graphene is a single layer of graphite 

Linking the Bonding & Properties 

• Graphene is extremely strong but also amazingly light

  • It would take an elephant with excellent balance to break through a sheet of graphene

  • It is very strong due to its unbroken pattern and the strong covalent bonds between the carbon atoms

  • Even when patches of graphene are stitched together, it remains the strongest material out there

• Graphene conducts heat and electricity

  • It has delocalised electrons 

  • These are free to move and carry a charge

Carbon Nanotubes 

• Graphene can also be rolled into a cylinder to produce an interesting type of fullerene called a nanotube

• These have high tensile strength but a low density and are resistant to breaking or stretching

• As in graphene, nanotubes can also conduct electricity which makes them useful in composites and specialised materials, electronics and nanotechnology

• Carbon nano-tubes have a much smaller scale structure than carbon fibres and are not what is used in the manufacture of bikes and tennis rackets

Diagram to show the structure of a carbon nanotube

A nanotube can be produced from a rolled sheet of graphene

Linking the Bonding & Properties 

• Carbon nanotubes conduct electricity

  • Each carbon is bonded to three other carbon atoms leaving one electron per atom unbonded 

  • These delocalised electrons are free to move and carry a charge

• Carbon nanotubes have a high melting point

  • There are strong covalent bonds between carbon atoms

  • These need lots of energy to overcome

• Carbon nanotubes have a low density and are very strong 

  • Each carbon atom is joined together by strong covalent bonds 

  • These require lots of force to break