-Paul Hughes
http://www.enthea.org/
On Sat, Mar 24, 2012 at 5:34 AM, Giovanni Lostumbo
<giovanni...@gmail.com> wrote:
> I've been looking into printing ultrafilters- perhaps nanometer wide
> membrane pores could be etched with lasers this way as well...
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For bulk quantities, getting access to graphite may be more complicated,
but definitely easier than accessing lithium. The world production comes
from mining of naturally ocurring mineral but also from synthesis from
oil. So it is, in principle, slightly less centralized than oil, which
is not very centralized itself.
-David
http://www.asbury.com/images/pdf/SyntheticGraphitePartI.pdf
It seems that the first process to do so was discovered in 1890. It
requires very high temperatures (2300-3000�C), which is tricky, because
you can't get that high using flames. Not any carbon compound can be
used, obviously.
-David
On 03/27/2012 10:13 PM, Paul Hughes wrote:
Chemistry in general is easy.
> nitrate and potassium permanganate (apart from graphite, of course) and
> mild temperatures. As you say, graphite can be found in every day
> pencils. Although a pencil may have very little graphite on it, the
Not pure graphite. It's typically a clay/graphite mix. There are few
locations where more or less pure graphite is mineable, so in practice
it's made synthetically.
For nanostuff it's all HOPG, aka highly oriented pyrographite. Made
from gas phase.
> interesting thing about graphene is that you don't really need too much
> to make something useful out of it. The capacitor built by these guys at
> UCLA comprised just a couple of 100-micron-thick layers of a few squared
> centimeters each.
Exactly, just buy some HOPG and experiment away.
> For bulk quantities, getting access to graphite may be more complicated,
I don't see why.
> but definitely easier than accessing lithium. The world production comes
I also don't see why. Lithium is cheap enough.
> from mining of naturally ocurring mineral but also from synthesis from
> oil. So it is, in principle, slightly less centralized than oil, which
> is not very centralized itself.
Carbon is everywhere, both in carbonates of the crust, air, biomass.
The difficulty is low-defect high-purity stuff, which is however still
much easier and cheaper to make the semiconductor-grade monocrystaline Si.
Not tricky at all, electric arc. The difficulty with HOPG is that
you need high-pressure to boot. That's for bulk, you can grow it
on metal (e.g. Cu) from gas phase.
I don't think that would work, because its well below the diffraction
limit (which is tricky to get around, uses interference)... i.e. Intel
is only doing 14 nm fab which is still in lab research stage
--
Nathan McCorkle
Rochester Institute of Technology
College of Science, Biotechnology/Bioinformatics
On Sat, Mar 24, 2012 at 8:34 AM, Giovanni Lostumbo
For me the really cool thing would be that you could somehow make
crystalline graphite out of biomass, for instance, or out of "domestic"
plastics (PET, ABS), something that anyone can get where they live. I
guess that's out of question. Correct me if I'm wrong, because I'd be
very interested in that possibility.
This method is supposed to make graphene oxide form graphite with a high yield,
and it is wet chemistry with sulfuric acid, so the clay would just be dissolved silica
and dirt, and probably just reduce yield. Have not found a full text outside a paywall yet,
getting my UT library card updated soon... Dr. Tour brags it was one of the top twenty downloads
from ACS Nano, (through the paywall $$$).
Marcano, D. C.; Kosynkin, D. V.; Berlin, J. M.; Sinitskii, A.; Sun, Z.; Slesarev, A.; Alemany, L. B.; Lu, W.; Tour, J. M.
“Improved Synthesis of Graphene Oxide,” ACS Nano 2010, 4, 4806-4814.
"Rice University Professor James Tour and graduate student Daniela Marcano discuss their ACS Nano paper "Improved Synthesis of
Graphene Oxide," one of the most-accessed ACS journal articles for 2010."
They improved Hummers procedure, which involves sifting and filtering...which probably tolerates
some clay in it... It's a procedure for processing ore from the earth...
http://www.youtube.com/watch?v=sTooYDp1KD4&NR=1&feature=endscreen
You will get lithium metal from any large chemical supplier (as a business;
both elementary iodine and lithium are watched due to clandestine drug production).
Lithium will be also easily recoverable from lithium batteries.
> that graphite "is actually a very centralized material". Not really that
> it is expensive, but that it is something you can't easily grow in your
> backyard, so you depend on some big corporation to get access to it. I
But you have no problems growing either graphene or diamond films from
gas phase or almost a dozen of other methods.
http://en.wikipedia.org/wiki/Graphene
> don't know if I grasped his intention correctly.
>
> For me the really cool thing would be that you could somehow make
> crystalline graphite out of biomass, for instance, or out of "domestic"
You can make graphene from sucrose or plexiglas.
> plastics (PET, ABS), something that anyone can get where they live. I
You should be able to get high-purity carbon from thermolysis of
natural gas (methane). You can probably produce straight graphite
by building a microwave-powered methane thermolysis reactor.
> guess that's out of question. Correct me if I'm wrong, because I'd be
> very interested in that possibility.
I don't see much reasons for making straight graphite, other than to
convert it to graphite oxide for graphene production. DIY will most likely
want to make high-quality graphene in small batches.
In general graphene isn't all that good as a drop-in replacement for
Si, you'd do better with carbon nanotube (different chiralities/doped)
and graphene nanoribbons.
> I read that the proportion in the mix depends on the hardness of the
> pencil. Do you think a really soft pencil could serve as a source for
> "pure-enough" graphite?
It depends. For what purpose? You can definitely use it to do chemistry
with. I've used as graphite electrodes for electrolysis (or
electrosynthesis). I presume you'll get some graphite oxide on the
anode with sulfuric acid or KOH. Unglazed clay will do as a makeshift
semipermeable membrane to separate the electrolyte spaces while
allowing ions to move.
You can probably anneal it quite a lot by electric heating.
It would be interesting to see what you could do to small carbon
samples in a suitable crucible in your microwave. Electrowelding
can do a lot more.
You can actually exfoliate a reduce graphite oxide in a kitchen
microwave http://bucky-central.me.utexas.edu/RuoffsPDFs/215.pdf
If you start with this, and do Hummer's procedure to get graphene oxide,
will the crystal size stay tiny?
Will starting crystal size matter for results of being a supercapacitor
anode, where large surface area is a plus?
At some point size of crystals must matter for conductivity, which is
also a desirable part of supercapacitor terminals.
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I'm planning to research it further. Since so many of the papers are non-free,
that means trips to the university library. As in semiconductors, and all batteries,
the big thing is the contacts to get to a copper wire from the thin graphene films.
John
"Researchers placed graphite and frozen carbon dioxide in a ball miller, which is a canister filled
with stainless steel balls. The canister was turned for two days and the mechanical force produced
flakes of graphite with edges essentially opened up to chemical interaction by carboxylic acid
formed during the milling.
The carboxylated edges make the graphite soluble in a class of solvents called protic solvents,
which include water and methanol, and another class called polar aprotic solvents, which includes
dimethyl sulfoxide.
Once dispersed in a solvent, the flakes separate into graphene naonsheets of five or fewer layers.
To test whether the material would work in direct formation of molded objects for electronic
applications, samples were compressed into pellets. In a comparison, these pellets were 688 times
better at conducting electricity than pellets yielded from the acid oxidation of graphite.
After heating the pellets at 900 degrees Celsius for two hours, the edges of the ball-mill–derived
sheets were decarboxylated, that is, the edges of the nanosheets became linked with strong hydrogen
bonding to neighboring sheets, remaining cohesive. The compressed acid-oxidation pellet shattered
during heating.
To form large-area graphene nanosheet films, a solution of solvent and the edge-carboxylated
graphene nanosheets was cast on silicon wafers 3.5 centimeters by 5 centimeters, and heated to 900
degrees Celsius. Again, the heat decarboxylated the edges, which then bonded with edges of
neighboring pieces. The researchers say this process is limited only by the size of the wafer. The
electrical conductivity of the resultant large-area films, even at a high optical transmittance, was
still much higher than that of their counterparts from the acid oxidation.
By using ammonia or sulfur trioxide as substitutes for dry ice and by using different solvents, “you
can customize the edges for different applications,” Baek said. “You can customize for electronics,
supercapacitors, metal-free catalysts to replace platinum in fuel cells. You can customize the edges
to assemble in two-dimensional and three-dimensional structures."
http://blog.case.edu/think/2012/03/26/simple_cheap_way_to_massproduce_graphene_nanosheets
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Depends on the pressure. You don't want to pressurize
metal containers at home.
In general home chemistry and novices don't mix well.
Some are naturals at it, some just can't do it even
with training.
> If it can be done with graphite, dry ice and a plain ball mill it should be
> able to be done at home.
>
> Can anyone confirm if this is possible or impossible?
Depends on your home lab and your skill set.
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______________________________________________________________
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Another process which looks doable at home is spinning nanotube fibers,
http://www.utdallas.edu/news/2011/1/24-8251_UT-Dallas-Researchers-Spin-Nanotech-Breakthrough_article.html
. The process involves drawing nanotubes off of a nanotube forest. The videos I've seen make it look
fairly easy, but when I contacted the researchers I found it hard to get details beyond what was in
the publications. Filed forms and NDA to gain access to details, never heard back. It looks like the
nanotube web can be drawn by gently laying adhesive tape on top of forest, then quickly drawing. the
tubes break off from substrate and cling to each other, creating fibers.
On 4/4/2012 1:24 PM, Robb Greathouse wrote:
> Lab skills are pretty good. We have done basic chemistry, son is in third year of synthetic chemistry.
>
> Agree on the pressurized container issue. High temperatures and high pressures need a lot of safety
> precautions that aren't available in a home workshop.
>
> That was what I was wondering. The chemicals involved are fairly safe. I wanted to know if there
> were any prohibitive steps. High pressure would be one, high temperature would be another.
>
> From the explanation it sounds like there is nothing prohibitive. I want to check if anyone knows
> of anything.
>
>
>
> On Wed, Apr 4, 2012 at 6:13 PM, Eugen Leitl <eu...@leitl.org <mailto:eu...@leitl.org>> wrote:
>
> On Wed, Apr 04, 2012 at 05:40:44PM +0000, Robb Greathouse wrote:
> > Could this be done at home, by a novice?
>
> Depends on the pressure. You don't want to pressurize
> metal containers at home.
>
> In general home chemistry and novices don't mix well.
> Some are naturals at it, some just can't do it even
> with training.
>
> > If it can be done with graphite, dry ice and a plain ball mill it should be
> > able to be done at home.
> >
> > Can anyone confirm if this is possible or impossible?
>
> Depends on your home lab and your skill set.
>
> > Robb,
> >
> > On Wed, Mar 28, 2012 at 1:48 PM, m d <2md...@gmail.com <mailto:2md...@gmail.com>> wrote:
> >
> > > This method looks promising to make functionalized graphene in bulk
> > > quantity:
> > >
> > > "Researchers placed graphite and frozen carbon dioxide in a ball miller,
> > > which is a canister filled
> > > with stainless steel balls. The canister was turned for two days and the
> > > mechanical force produced
> > > flakes of graphite with edges essentially opened up to chemical
> > > interaction by carboxylic acid
> > > formed during the milling.
> > >
> > > The carboxylated edges make the graphite soluble in a class of solvents
> > > called protic solvents,
> > > which include water and methanol, and another class called polar aprotic
> > > solvents, which includes
> > > dimethyl sulfoxide.
> > >
> > > Once dispersed in a solvent, the flakes separate into graphene naonsheets
> > > of five or fewer layers.
> > >
> > > To test whether the material would work in direct formation of molded
> > > objects for electronic
> > > applications, samples were compressed into pellets. In a comparison, these
> > > pellets were 688 times
> > > better at conducting electricity than pellets yielded from the acid
> > > oxidation of graphite.
> > >
> > > After heating the pellets at 900 degrees Celsius for two hours, the edges
> > > of the ball-mill�derived
> > > sheets were decarboxylated, that is, the edges of the nanosheets became
> > > linked with strong hydrogen
> > > bonding to neighboring sheets, remaining cohesive. The compressed
> > > acid-oxidation pellet shattered
> > > during heating.
> > >
> > > To form large-area graphene nanosheet films, a solution of solvent and the
> > > edge-carboxylated
> > > graphene nanosheets was cast on silicon wafers 3.5 centimeters by 5
> > > centimeters, and heated to 900
> > > degrees Celsius. Again, the heat decarboxylated the edges, which then
> > > bonded with edges of
> > > neighboring pieces. The researchers say this process is limited only by
> > > the size of the wafer. The
> > > electrical conductivity of the resultant large-area films, even at a high
> > > optical transmittance, was
> > > still much higher than that of their counterparts from the acid oxidation.
> > >
> > > By using ammonia or sulfur trioxide as substitutes for dry ice and by
> > > using different solvents, �you
> > > can customize the edges for different applications,� Baek said. �You can
> > > customize for electronics,
> > > supercapacitors, metal-free catalysts to replace platinum in fuel cells.
> > > You can customize the edges
> > > to assemble in two-dimensional and three-dimensional structures."
> > >
> > >
> > > http://blog.case.edu/think/2012/03/26/simple_cheap_way_to_massproduce_graphene_nanosheets
> > >
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The process of making graphene oxide (used for the Laserscribe DVD method of making graphene): www.graphene-battery.net/graphene.htmThe chemistry is doable at home, but it's really not safe to do so because it involves a water bath and some nasty acids.I'm the author of the website, if you notice any info that could contribute, let me know.
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