[Q] Singlewall nanotube - SWNT OR Multiwall nanotube - MWNT

[JoannRobinson]

Hello All

 

Singlewall nanotube - SWNT OR Multiwall nanotube - MWNT

 

whats the difference between Singlewall nanotube - SWNT OR Multiwall nanotube - MWNT Method ?

 

[JoannRobinson]

Any Response ?

Please I want to brief information about my question.

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Carbon Nanotubes

[Theory5]

Wiki defines the single wall nanotube as

The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder.

The multiwall nanotube is

Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite.

[Pyrotex]

Hello Joann,

I think you're asking for the difference between the "methods" of producing single and multi- walled nanotubes, right? Or between the nanotubes themselves? I'll answer both.

 

Simply, a single wall nanotube, SWNT, can be thought of as a long cylindrical "balloon" made up of just ONE layer -- the layer itself is a single sheet of carbon atoms in a hexagonal arrangement.

 

A multi-wall nanotube, MWNT, can be thought of as an identical looking "balloon", but made up of SEVERL layers -- each layer being identical with a SWNT. Or think of the MWNT as a bunch of SWNTs nested inside each other.

 

Interesting tidbit: Each SWMT consists entirely of carbon atoms arranged in hexagons, EXCEPT for exactly 12 pentagons. There are 5 pentagons in a circle at each "end" of the nanotube. This pattern is probably already familiar to you: the soccer ball. It is made up of numerous hexagons and 12 pentagons. :naughty:

 

Now--the difference in the METHODS for making SWNT & MWNT.

I dunno the details and I don't have time right now to do the web searching, but I can make an educated guess, since I'm a physicist. (We know everything! :) )

 

NT are basically made by creating an electric arc between two carbon electrodes, in a pure helium atmosphere. The helium is pumped through at some speed to carry the "ash" away from the electrodes, into another container, where the "ash" is dissolved in a liquid, like benzene. The "ash" consists of lots of stuff, including SWNT and MWNT of all different sizes and lengths. Then the solution is purified using several chemical and/or ionic techniques to separate the kind of SWNT or MWNT you're looking for.

 

Now, we have a number of parameters that can be controlled -- and I think these parameters are what cause the "ash" to be mostly SWNT at some settings, or MWNT at other settings. I know there has been a lot of experimentation playiing around with these parameters.

 

They are:

Doping of the electrodes (trace amounts of non-Carbon atoms or molecules)

Electrical current of the carbon arc (Amperes)

Voltage of the carbon arc (Volts)

Gas pressure of the helium (pounds/sq.in.)

Temperature of the helium

Velocity of the helium through the electrodes

Doping of the helium (trace amounts of non-Helium atoms or molecules)

The chemical nature of the solvent (benzene or toluene or whatever)

 

There! Chances are excellent, that the difference between the SWNT method and the MWNT method is really just a combination of differences between these parameters.

 

Good luck.

[JoannRobinson]

Hello Joann,

I think you're asking for the difference between the "methods" of producing single and multi- walled nanotubes, right? Or between the nanotubes themselves? I'll answer both.

 

Simply, a single wall nanotube, SWNT, can be thought of as a long cylindrical "balloon" made up of just ONE layer -- the layer itself is a single sheet of carbon atoms in a hexagonal arrangement.

 

A multi-wall nanotube, MWNT, can be thought of as an identical looking "balloon", but made up of SEVERL layers -- each layer being identical with a SWNT. Or think of the MWNT as a bunch of SWNTs nested inside each other.

 

Interesting tidbit: Each SWMT consists entirely of carbon atoms arranged in hexagons, EXCEPT for exactly 12 pentagons. There are 5 pentagons in a circle at each "end" of the nanotube. This pattern is probably already familiar to you: the soccer ball. It is made up of numerous hexagons and 12 pentagons. ;)

 

Now--the difference in the METHODS for making SWNT & MWNT.

I dunno the details and I don't have time right now to do the web searching, but I can make an educated guess, since I'm a physicist. (We know everything! ;) )

 

NT are basically made by creating an electric arc between two carbon electrodes, in a pure helium atmosphere. The helium is pumped through at some speed to carry the "ash" away from the electrodes, into another container, where the "ash" is dissolved in a liquid, like benzene. The "ash" consists of lots of stuff, including SWNT and MWNT of all different sizes and lengths. Then the solution is purified using several chemical and/or ionic techniques to separate the kind of SWNT or MWNT you're looking for.

 

Now, we have a number of parameters that can be controlled -- and I think these parameters are what cause the "ash" to be mostly SWNT at some settings, or MWNT at other settings. I know there has been a lot of experimentation playiing around with these parameters.

 

They are:

Doping of the electrodes (trace amounts of non-Carbon atoms or molecules)

Electrical current of the carbon arc (Amperes)

Voltage of the carbon arc (Volts)

Gas pressure of the helium (pounds/sq.in.)

Temperature of the helium

Velocity of the helium through the electrodes

Doping of the helium (trace amounts of non-Helium atoms or molecules)

The chemical nature of the solvent (benzene or toluene or whatever)

 

There! Chances are excellent, that the difference between the SWNT method and the MWNT method is really just a combination of differences between these parameters.

 

Good luck.

 

Hi,

 

I am very appreciate for your answer here it's excellent Answer.

 

Thank .....

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Carbon Nanotubes