John Jijadi
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conductor polymer
any easy ways to make conductive polymer in a secondary school laboratory?
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peach
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Add carbon to silicone sealant?
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ScienceSquirrel
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Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
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Zzzzzz! 
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peach
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Organic semiconductors?
| Quote: | | In 1862, Henry Letheby obtained a partly conductive material by anodic oxidation of aniline in sulfuric acid. The material was probably polyaniline
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| Quote: | | In 1977, Shirakawa et al. reported high conductivity in oxidized and iodine-doped polyacetylene.[9] They received the 2000 Nobel prize in Chemistry
for "The discovery and development of conductive polymers" [10]. In view of the many previous reports of similar compounds, the "discovery" assignment
is contested |
Bonus points, you can print them with a deskjet and one of them is in your skin.
[Edited on 1-2-2011 by peach]
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smuv
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polyacetylene.
You can make polyacetylene (with some chain defects) from thermolysis of polyvinyl acetate polymers. When the quantitative amount of acetic acid is
collected the still pot will contain a colored polymer, largely consisting of polyacetylene (at least so I have read).
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peach
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Ooooooo, thanks for that. Nifty stuff, organic semiconductors starting from the ubiquitous PVA glue pots of kids TV.
I'll have to do some googling to look at the doping ideas. But it's now 7.30am and I haven't been to bed yet, so it's probably one for tomorrow.
It would be sciencedamn amazing if one could produce an ink jettable form of the polymer so simply.
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vulture
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FeCl3 polymerization of polythiophene, add I2 as dopant. Conductivity isn't great though.
PEDOT PSS is widely used in antistatic coatings, but is not really easy to synthesize in a highschool setting.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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smuv
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http://books.google.com/books?id=AY__YWnIE_4C&printsec=f...
I'm pretty sure I read it in one of the references in the polyvinyl acetate article of the above book. It is a real interesting book, if anyone has
full online access to it, I would be very thankful if someone could share it.
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paulr1234
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This one doesn't require anything too exotic or dangerous:
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/Nanotube-PrepP...
However is was fashioned as a bending EAP not just as a conductor but it might make a good demo, especially as you can also show a practical
application.
I've used a cheap vibrating jewelry cleaner instead of an expensive lab sonicator.
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Zaratukhshthra
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polyacetylene can't be stored open door (it's unstable). IMHO the best choice of conducting polymers for amateur chemists is polyaniline (PANI). It's
pretty easy to synthesis. All you need is an acidic aq aniline solution and a) an oxidizer ((NH4)2S2O8, FeCl3, K2Cr2O7....) or b) two steel plates and
a power supply.
there are many cool things you can do with it. e.g. by changing the potential of a PANI coated electrode. it instantly changes color (reversibly)
between transparent (pale yellow, leucoemeraldine = reduced form, insulator), green (emeraldine = half oxidized, conductive) and blue (pernigraniline
= fully oxidized, insulator).
Also at acidic pHs it's conductive and green in color (emerldine salt). At higher pHs it becomes insulator and blue in color (emeraldine base)
[Edited on 4-2-2011 by Zaratukhshthra]
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DNA
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Add nano carbontubes or make an alternating double bond polymer like this:
(-=-=-=-=-=-)n this will also conduct elecricity.
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Zaratukhshthra
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Quote: Originally posted by DNA  | ...or make an alternating double bond polymer like this:
(-=-=-=-=-=-)n this will also conduct elecricity. |
conjugation is not the whole story. you need to either oxidize or reduce the conjugated polymer, so that freely moving charge carriers appear.
for more information search for polaron+bipolaron+soliton+"conducting polymers"
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DJF90
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Suzuki coupling of p-bromobenzeneboronic acid in the presence of a base (Na2CO3, KF, etc) will produce PPP (thats poly-para-phenylene) - without a
dopant its an insulator but partial oxidation (e.g. with iodine) or reduction will yield a conductive solid (conductivity is 2-4 magnitudes less than
copper metal - approximately similar to lead). This material is also electroluminescent, and if Peach requires I'll provide the details I have on that
property. What DNA posts is actually polyacetylene - I guess he doesnt realise his conjugated polymer has a name... But Zaratukhshthra is right in
saying it needs doping in order for it to become a metallic conductor - otherwise its a semiconducting material. Doping produces "mid gap states",
allowing for metallic conduction.
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paulr1234
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@DJF90
I don't suppose you have a reference or synthesis work up for this?
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DJF90
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http://ifile.it/a15p6i8
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peach
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Electro-luminescence! A win win situation.
Polyacetylene is also the back bone of melanin; skin pigments.
I wonder if any of those are more stable yet also decent polymer conductors.
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Adas
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I would love to have some stable, good-conducting polymer electrodes. One could possibly electrolyse anything with them without damage
Rest In Pieces!
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kristofvagyok
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Awesome topic, sad that I didn't discovered it yet!
The most easily "home made" conductive polymer is polyaniline what could be really easily made via mild oxidation of aniline. If it's pure than it has
an awesome blue of green color in solution, I think that if someone wants to start experiments than this would be a good point.
The polyacetylene is aint to easy to make, Ziegler-Natta catalyst is needed for making it, not an easy task for a home chemist.
Polypyrrole is also a great thing to make, it is really easily made, pyrrole is also not a really hard task for a home chemist (could be made from
mucic acid amide via heating) and coud be polymerized electrochemically as seen here:
-that black thing is the electrochemically formed doped polypyrrole.
I have written a homework not long ago from conductive polymers, it's mainly from wiki and a few other sources but if someone knows just a little than
it could be useful to read it.
Attachment: conductive polymers homework.pdf (141kB)
This file has been downloaded 951 times
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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Rich_Insane
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I used to work with conductive polymers a lot. Melanin is one great biopolymer [Science, vol 183, 853-855 (1974)]. I recall that I grew common
mushrooms and exposed them to UVA light (390 nm), which causes them to form a thick black colored layer on the cap. The polymer itself is soluble in
alkaline solutions (pH 10 and up) and highly insoluble in acid.
I also know that there are charge transfer complexes like the quinhydrone complex and such, which are somewhat OTC.
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Jekyll
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| Quote: Originally posted by Adas | | I would love to have some stable, good-conducting polymer electrodes. One could possibly electrolyse anything with them without damage |
Metallic fibers, particularly stainless steel fibers (expensive), make an excellent conductive polymer reinforcement, as do the cheaper aluminum
coated glass fibers, aluminum foil sliced ribbons and melt–spun aluminum fibers. Stainless might possibly work for a conductive, fiber-reinforced
polymer electrode.
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