Making Graphene could KILL you... but we did it anyway?!

[Music] I keep listening [Music] hi you've probably heard of graphene the reason there's so much interest in this material is because it promises to revolutionize Electronics sensors Computing energy storage and all kinds of Structural Engineering the reason is its physical properties are simply off the charts graphene has 10 times the thermal conductivity of copper twice that of diamond it's higher than any other known material it conducts electricity better than any metal better than silver and its coefficient of friction is three times lower than Teflon mechanically it simply pegs the meter graphene is 200 times stronger than steel at one-fifth the weight to put that in perspective aluminum has three times the strength to weight ratio of Steel that's why they build airplanes out of it graphite or carbon fiber has 15 times the strength to weight ratio graphene 1000 times in addition it's extremely tough Ness is the measure of how much work you have to do to break something force times distance something can be very strong like glass or carbon fiber but because you can only stretch it a fraction of one percent before it breaks you have to apply a fair amount of force but for a very short distance you can break it with a hammer graphene can stretch up to five percent of its original length before it ruptures so you have to use an enormous amount of force for a very long distance it's not indestructible but it's getting pretty close and you can imagine what this would do for architectural engineering safety equipment sporting equipment Aerospace space elevators the list goes on the reason it has the properties it does is well understood graphene is pure carbon arranged in a two-dimensional molecule one atom thick and indeterminate in the X and Y Direction it's a sheet each of the individual carbon atoms is bonded to three neighboring carbons with an extremely strong carbon-to-carbon covalent bond it's one of the strongest in nature the result is this hexagonal or honeycomb type of arrangement the reason it has such high thermal conductivity is the transport of thermal energy through a material is the propagation of thermal vibrations through that material because graphene is so stiff the speed of sound is so high that propagation is very rapid as it moves across a sheet of graphene the reason it has such high electrical conductivity is because of the 2D nature of its molecule the electromagnetic field across the surface is homogeneous so current can flow across like water with very little obstruction the reason it's so strong is because of the extremely strong carbon to carbon bonds and the reason it's so tough is because of the macroscopic structure of this hexagonal Arrangement you can stretch and compress this substantially without changing the angles of the bond very much now this is just carbon and carbon is everywhere I'm 20 carbon this room is filled with carbon we breathe carbon it's widely available and it's cheap so why don't we see this already all over industry the simple answer is it's pretty hard to come by and it's particularly frustrating because we are surrounded by it this pencil contains a substantial amount of graphene this Rod that we use to fabricate our rocket nozzles is mostly graphene because graphite is mostly graphene when you take individual sheets of graphene and you line them up so that the atom of one layer lines up with the center of the hexagons of the neighboring layer they get as close together as they can this is the stable bond that occurs in graphite however unlike the tremendously strong bonds between the carbons in the graphene sheets the bonds between these individual sheets is very very weak so thermal conductivity electrical conductivity Between the Sheets not so good and because these sheets can peel apart like playing cards graphite doesn't express the same mechanical properties of graphene but we're kind of in a catch-22 because even though these sheets are relatively weakly bonded it's still strong enough that it's hard for us to get it apart but it can be done early on when researchers were studying graphene they came up with a really clever method to peel away the individual sheets of graphene from a piece of graphite if you take adhesive tape Scotch tape and you apply it to the surface of a piece of graphite like this just shmoots it down and peel it up and what you end up with is a very thin layer of graphite flakes like this if now what you do is you take another piece of Scotch tape and stick them together Sticky Side to Sticky Side and let's see if I can do this without imitating Milton from the office here like this and then simply peel them apart like this you end up with very thin layers of graphite and if you do this three or four times you end up with a single Atomic layer of graphene it really works you can now take this into your laboratory put it into your electron microscope and you can study it the problem is if you want to build a bridge there isn't enough Scotch tape in the world to produce the amount of graphene you need Yep this method is scalable this is called electrochemical exfoliation and it became popular about 10 years ago and you can see why what you need is a source of some graphite and in our case today we're using these thin flexible sheets that you can buy in large rolls at low cost and it's typically sold to make gaskets and liners for high temperature furnaces you cut a couple of strips from the graphite place it inside of a container and hook it up to a power supply then you add an electrolyte solution typically ammonium sulfate 0.2 to 0.4 molar or 25 to 50 grams in a liter of pure water add the electrolyte to the container [Applause] and then turn on the power now immediately you start to see these bubbles forming what we're doing is we're electrolyzing the water and we're forming a hydrogen and oxygen gas but in the process we're making hydronium and hydroxide ions in the solution the negatively charged hydroxide ions are attracted over to the positive anode and what they do is they sort of get into that anode they're driven into the anode by the attraction and begin to try to separate apart those individual sheets of graphene they're followed by the even larger sulfate ions which wedge their way further between and because both of these ions are larger in diameter than the normal spacing between the sheets they exfoliated they delaminated they separated away now obviously this is very attractive because the equipment needed is super simple and the scalability of this is tremendous you could bring this up to swimming pool size the problem is it doesn't work very well the reason is that unlike with the tape where we're pulling away one sheet at a time this process of exfoliation is working on all the millions of layers of graphene in the graphite in the anode simultaneously so we might get lucky and separate layer 1 from Layer Two but the next layer that comes free may be layer 300 from 301 10 000 from Ten Thousand and One what you end up with in solution is a tiny bit of graphene and a large number of thin flakes of graphite furthermore you contaminate the graphene with the oxygen the hydrogen and the sulfur in the electrolyte so you have to do post processing to clean it up now there are ways to mitigate some of this pre-separation of the graphite but they don't work particularly well if they did we would be seeing graphene on the market in ton quantities at low cost and we don't both of these methods that I've just demonstrated are called top-down synthesis you start with the graphite and you separate out the graphene the other approach I'm going to turn this off before I set up an explosive environment in here is called bottom-up synthesis you start with the carbon and you grow the graphene from scratch and that too is done all the time in large chemical vapor deposition machines with large vacuum Chambers they will remove the air and they will introduce a carbon donor typically methane and a buffer gas like helium or Argon then they will create a plasma inside of the chamber which rips apart the methane freeing up the hydrogen and the carbon and under an electromagnetic field the carbon is drawn down to the bottom where it deposits usually on a copper plate this really works because the carbon to carbon bond in graphene is the most stable of all carbon bonds it naturally grows graphene without any further guidance from us it wants to make graphene and it does and what's funny is if you actually change the parameters in the chamber a little bit and replace the copper with a different road map a different lattice to kind of guide the carbon's growth you can actually induce it to form the second most stable form of carbon Diamond something for a future video the problem with this though is we're forming graphene in picogram quantities trillionths of a gram with hundreds of thousands of dollars worth of equipment again we're not going to build a bridge enter Rice University a couple of years ago a graduate student named UE long in the laboratory of Dr James tour developed a technique called flash graphene that uses substantially less expensive equipment and produces high quality graphene at orders of magnitude higher production rate than the cvd machine and that is what we're going to show you how to do today now to start with you need a glass tube and in our case we're using quartz and you need a carbon source and in this case we're using carbon black or soot now it's an interesting thing in the paper put out of rice they indicated it really doesn't matter what you start with as the carbon Source you can use carbon black but you can also use coal ground up tires coffee grounds Beetles the reason it doesn't matter is because we're going to heat this carbon to over 3 100 Kelvin and when we do no matter what you started out with all of the chemical bonds are going to break where the magic happens is in the cooling just like in the chemical vapor deposition machine once the carbon is freed up and it begins to cool it will naturally grow graphene all on its own and if we cool it slowly what will happen is the individual graphene sheets will begin to line up and stack and we will build graphite we don't want that however if you cool this in milliseconds the individual sheets don't have time to do that annealing they can end up freezing in a shifted mode or twisted or even tipped form they call this turbostratic graphene for some reason or turbostratic graphite and the main point though is that because the bonds between the material are so weak once we end up getting the graphene out we can easily exfoliate this we can use something as simple as a mortar and pestle we've done that it works or you can use something like a sonicator about 100 Watts 20 30 minutes and you break up all the individual sheets of graphene so let me show you how we prepare this tube okay in the paper they recommend using quartz which is a good choice it's got a high temperature tolerance and it's very tough they also recommend using a thin wall quartz tube to speed the cooling and improve the graphene production that doesn't make sense because all of the cooling is going to be radiative black body radiation cooling it's not conduction so it doesn't matter how thick the tube is because it's completely transparent to all of the waves of light that the hot carbon will make and a heavier wall tube is just a little more robust less likely to break what we are using is a seven millimeter ID 11 millimeter OD two millimeter wall thickness medium to heavy wall quartz two we want to cut off 100 millimeters or four inches now if you had a diamond saw you could just cut across here but a real easy technique is simply to fracture it so what I'm going to do is create a little stress point that will allow it to fracture in a controlled way now they make diamond scribes for this but you really don't need to do that you can use a triangular machinist file it works just fine so at the Mark that I've already made at 100 millimeters I'm going to take this little scribe and I'm going to draw it across and scratch it now if you glass blowers out there I know just a little Nick but the point is with this heavy wall and tough quartz I find that I have to make a pretty decent scratch to get a lot reliable break so I'm going to give this a couple of good scores to ensure the brake then there is a little trick I learned many years ago from a glass blower and don't know why it works but it really does you need to wet the scratch some of them will actually take the tube and they'll lick it but you know glass dust so what I'm going to do is just take a Q-tip a little water on it and wet it like that then if you take this and put your thumbs on either side of the scratch like this opposite the scratch so it's away from you then aim it down at the floor just in case things go kind of sideways and give it a little snap just like that and you end up with a very nice crack and even if it's a little rough doesn't really matter we're only using the middle section now we have to prepare the electrodes what they recommend using is a fine mesh copper wool you can get this on Amazon and it's a good choice because copper has very high thermal and electrical conduction it's also very malleable so you can form a very nice conformable compressible electrode to carry the electricity that we're going to send into the carbon to prepare this what you do is you measure off about a half a gram of this wool and you can just sort of pull it off like this this I know this a little much from experience and we'll weigh this see how close I guessed 70. let's take off a little bit and this doesn't have to be precise you could use a gram the only reason I'm trying to be a little close is because I want to use the minimal amount so that I don't use up all the internal volume of the tube and don't have any room for the carbon now the next trick is you put it in your hand and for all of those little threads you want to gather them together so you just roll it up like a spicy meatball like that nice and then a little Sushi action here into a little cylinder like that and then we're going to insert this into the end of the tube sometimes a little twisting action will help but usually if you've rolled it well enough this will go in pretty easily once you get it in the end of the tube like that then you want to conform this you want to compress this into a little pellet what I have to do that with is these tungsten welding rods these are quarter inch so 6.4 millimeters seven millimeter tube nice fit I placed this in this end here like this and then I take another tungsten welding rod in the other end like this and then I put it down and I hammer it with a board like this to form a nice compressed cylinder then I'm going to push this a little further down like this to give me the maximum amount of room for the carbon because it's very bulky now before we weigh out the carbon I'm going to do one more electrode and pre-form it because I'm not going to be able to take advantage I think it's always turning off of the hammering when I've got the soft carbon in there so away that 55 good enough or 550 milligrams so now again another little roll a little sticky rice action and then we're going to insert this in the end of a just a off cut short piece of tubing that I've got for this purpose and push it in the end of the tube now this time when I compress this I'm not going to compress it as vigorously as I did the last time I just want to form this so that I'll have a better shape when I put it in the other end of the tube then we'll just extrude that out like that now we're going to add the carbon black now we're going to zero this down and what we're going to want to do is add 150 milligrams 0.15 grams of carbon black okay now carbon black can be a little nasty it is like Moon dust it gets everywhere so you want to use the plastic you want to use gloves and I'm using these gloves here just for this purpose because they have a longer cuff and in addition you want to use a mask and probably this is not the right shirt for this purpose but I've done this enough I think I think I'll get away with it we'll find out so let's get this guy on okay I hate these things all right now the way to fill the tube get this right okay zeroed is to take a little craft stick you can get these at Walmart and you're going to scoop in there and carry up kind of a lump of carbon and then you're just going to sort of scrape it into the tube like this this takes a long time and we nearly have to fill the tube to get to the 150 milligrams that we're going to need this stuff is very bulky let's see how close we got halfway point one five I did it I really did it that was fast that was faster than most of them now just wipe this off take the pre-formed electrode that we've already made push this in the end of the tube like this like that and then with the tungsten Rod I'm just going to push this in a little bit to seat it I don't want to compress it not here let's go put this in the reactor flip this all right this is the reactor and the way this works is there's a fiberglass base that supports two conductive posts that I drilled holes in that allow the tungsten welding rods to slide in and out from each end and then they can be locked by a couple of set screws here into position now the way we set this up is I have an OHM meter hooked onto the back of here and I'm going to take the cylinder like this I'm going to place it in position on the end of this Rod push it all the way in like this and then with the set screw lock this into position so it doesn't move anymore then this is hooked up to an OHM meter back here and when I slide the other rod in here you'll start to see that the ohms slowly lower as I begin to manually compress the carbon between them see it going down now I'm going to bring this down to about three and a half ohms because we're compressing the carbon particles closer to each other now you could use this if you ever wanted to make custom resistors it's kind of a neat technique but one thing to keep in mind is you can only go one way once we've compressed this if you overshoot you can't back out it won't spring back and the goal here is to get to about three and a half ohms like this and then I'm going to go ahead and I'm going to attach this little jig on the back of this and then using the wrench and this screw I'm going to drive it in more precisely what we want to reach is 2.0 ohms and in all of the numbers I'm giving you for all of these parameters the voltages the quantities and the resistance you want to be within about 10 percent if you stay between say 1.8 and 2.2 ohms things are going to work but once you get outside of those numbers it begins to get kind of funky and you don't get very good productivity and approach this kind of slowly because if you overshoot like I said you're kind of stuck okay good now using the wrench and these set screws over here I'm going to lock this into place and then I'm going to remove The Jig on the end don't need this anymore put this over here now we don't need this anymore so I'm going to disconnect it now originally when I did this I had built a little acrylic barrier like this to go around the outside for the test for two reasons one if if this ever did explode what happens is the debris would be directed outward and not toward us it makes it a little safer and I normally give people the warning that you know be careful if you do this stuff at home because this stuff can be dangerous this voltage and current that we are using here is absolutely lethal the kinds of volts and amps that we're using in this system is very similar to the parameters used in a cardiac defibrillator except we're going to be using three times as much power as the highest setting in any cardiac defibrillator this will kill you so you've got to be very very careful now when we fired this I did this a couple dozen times I was not getting a very good result what was happening is I was getting very little graphene production and I was making a mess the carbon was all over the table it was on the inside of this guide couldn't figure it out and then I saw a short video clip that was put out by the group from rice to demonstrate this and I saw that they were doing this in a vacuum chamber now they didn't put that in the article but the point is it makes sense because even though we've compressed this carbon it's still about 90 percent air inside of there and when we Heat this up from 300 Kelvin room temperature to about 3 500 Kelvin the pressure of the air inside there goes to 12 atmospheres it blows the carbon out through the electrodes all over the table and doesn't leave anything left to react so we're going to do the reaction inside of a vacuum chamber so I'll put this in here just get it set up for you I'm going to slide this in here like this and we'll connect up the electrodes the feed through like this and now I'm going to explain the power system what we have here is a variable AC Transformer a variac this sends power through to a Mot or microwave oven Transformer that steps up the voltage we then send this through two rectifiers so it's a half wave rectification that sends pulses of DC current into this capacitor Bank each of these electrolytic capacitors are rated at 250 volts and they are 27 millifarads or 27 000 microfarads the three that you see in front are wired up in parallel so you add the capacitance 81 millifarads the two rows are in series so you cut the capacitance in half so the system capacitance is 40 millifarads behind here I have a little dump resistor that just drains residual current at the end to make things safe over here is the switch this is an scr which stands for silicon controlled rectifier it's an extremely high voltage High current high speed solid-state switch and the way that it works is that little red lead that you see coming out of the center of there is the trigger when you apply a three volt positive potential to that versus the ground it will close the switch and send about a thousand amps through the carbon heating it up the way I provide that is I take these two batteries wire them down from ground to three volts and send that into the trigger so when I push this button this will close and will heat up and make the graphene now in order to get the vacuum chamber up here I'm going to make a little bit of noise and we're going to start draining this down what holds the lid on is grab is air pressure so I have to Center this by hand before we hit the vacuum valve and then we'll start draining the vacuum [Music] [Applause] one two three and immediately you'll see the vacuum beginning to form this will take about two minutes or so to happen you also want to go down to about 100th of an atmosphere you can go lower but the problem is once you go much below that you lose the insulating properties of the air and you can get flashover or arcing between the conduct conduits so one percent or 7 600 microns or 7.6 millimeters that's the goal turn on my little vacuum gauge and we'll just give this a little time to work foreign about 6 700 microns of mercury it's a little low but it leaks slowly so we'll let that go that's a relief now what we're going to want to do is put approximately 7 200 joules per gram of carbon in order to heat it properly for the 150 milligrams we're using that works out to about 1100 joules or Watts seconds for 40 millifarads that works out to about 237 volts on the volt meter when we fire this now the other thing I've got over here is a photodiode hooked up to an oscilloscope in trigger mode so when we make the bright flash we can like this see a pulse that will give us how long it took to heat and how long it took to cool if you're doing this using the numbers that I give you you don't need this equipment this was necessary to kind of fine tune the numbers so that can save you a little bit of effort now the voltage here just a little trick whenever you're dealing with a high voltage source it's always a good idea to unplug it when you're working with it just in case and a double safe thing is to unplug it and put the plug or the cord where you're going to trip on it so that if you get tired and get a little sloppy you don't make a mistake and you say oh I think I unplugged it there's no way to miss this so we're going to go ahead plug this in and start charging this guy up now if you watch the volt meter over here I'm going to begin charging this and we're going to be looking for 237 volts see it going up 21 30. I'm actually going to overshoot this slightly and then maybe 241 242 and then when I turn this off what we'll do is allow the the resistor in the back to bleed it down at about a volt a second as soon as we hit 237 I'm going to fire it and we'll take a look and see what we made and be very careful when you're dealing with voltage and current like this this is very very dangerous our pressure is about 7 100 microns right now so that's good now getting close 220 230 okay now watch it decay 241 240 39 38 37. and that's it we just made graphene and you can see the spike over here we heated this up in a very small fraction of time each of those divisions is 20 milliseconds so it took about five milliseconds to heat and it took about 25 milliseconds for it to cool that's perfect the other thing you'll notice is there's still a little bit of residual voltage there and so before I touch anything metal I'm going to go ahead and give this a little bit of time to Decay down to a safe voltage and unplug it as well to make things super duper safe then we'll take this out and we'll see what we made all right you can see that our voltage is down to about 3.4 volts I'm unplugged everything should be safe let's break the vacuum so we'll enter air foreign do get a little bit of debris a little bit of the carbon black but a milligram of carbon black goes a very long way so most of the materials stayed inside the chamber or inside the reaction tube let's get this out and I'll show you what it looks like slide this out and I'm going to loosen this up a little bit [Music] and pull these back just a touch and if you look at the tube you see that gray shiny layer inside there in the middle that's graphene so I'm going to take this out of the reactor and we're going to take a look at what we made get this stuff out of here all right come on let's see what we've got in the reaction tube here [Music] okay now you're going to have to zoom in on this look very closely but inside of here what you'll see is these gray flakes like this these are the graphene some of them are a little smaller this is a particularly large one and you can see that in this particular one I'll move this over here this is an example of about five or six of these batches you can see the gray flakes over here as well now the black could be some residual carbon black if this isn't 100 conversion in addition some of the black might be graphite and even what they call wrinkled graphene very very small pieces of graphene that are sort of tied up in little knots like tissue paper they're not particularly useful the reason it's gray it's my understanding is that these turbostratic material because of the very loose interfaces between the different layers of graphene they work like interference filters almost like a diamond and that's why they appear to be gray and in addition to that when you grind them up and you actually separate it out they become black so problem now is to get rid of some of this additional material you want to try to filter this out and a little trick is to take a screen this is a little Five Dollar Fine mesh screen from Walmart and take out the electrodes we don't need those and just put this through here like this [Music] and shake it around the graphene tends to form larger flakes and so generally speaking you lose only a tiny bit of it through the holes but you'll keep most of the larger Flakes and the stuff that you really want you can then take this and to further separate it just put it into a beaker of water swirl it around for a minute let the heavier larger pieces of graphene settle to the bottom bottom and the lighter tiny pieces or the more buoyant pieces will float or stay in the water and then you just pour that off you don't need any filter paper just do what you do if you were gold panning and you end up with these nice gray flakes at the end now if you're still if you're still watching one question you might ask is how do I know that this is graphene and it's a good question if we had an electron microscope or an atomic Force microscope we could actually study this and look at the morphology but the Workhorse for evaluating graphene is called Raman spectroscopy kind of an interesting process if you take a laser and you shine it at a surface 99 plus percent of the light will be either scattered and reflected or absorbed by the material but a very small fraction of the light will interact with the molecular Bonds on the surface in some cases it will donate energy to those bonds and those photons will be redshifted reddened and in some cases it picks up energy from those bonds and it will be blue shifted the degree of shift is exquisitely sensitive to the nature of those Bonds in their environment so for example you can easily detect the oh bond in water and it's completely different from the oh Bond same Bond when it's in methanol or ethanol you can also identify the carbon to carbon bond in graphene and you can even distinguish the carbon to carbon bond in the inside of the sheet from the Ragged edges of the sheet furthermore if you have a couple of sheets of graphene together graphite that produces a different Peak and you can identify it now despite all the stuff that we have in this laboratory we don't have Raman spectroscopy I think I can call in a favor and get this analyzed but if we step back for just a second the reason I'm making this graphene is as a structural reinforcement so if I test this and it performs like graphene I don't care if I made marzipan so let me show you how we tested it all right what I did is I took some of these methyl cellulose shipping rods these are very thin plastic tubes you can get them with caps and when you put the cap on the bottom you can fill it and that's what I did I made up some mixtures of epoxy in one of the tubes I just placed pure epoxy in this tube I put in epoxy and 0.3 percent one part in 300 of the carbon black the precursor in this tube I put in 0.3 percent of graphite I simply took a razor blade and scraped it off the side of that Rod that I showed you earlier in the video in this Rod 0.3 percent of the graphene and in this one point six percent of the graphene so let's go Bend some beams all right so what we did in the hydraulic jack here is I set up this test jig it consists of a load cell on this side which reads up over here a support block on the other side and then a central block that is six millimeters shorter than these two so when we bend the beam six millimeters this aluminum tape will contact there and the volt ohmmeter at the top will give you a beep so when we hear the beep we'll notice how much force was necessary to bend each bar six millimeters let's get started this is the pure epoxy obviously make sure everything is centered zero kilograms let's go [Music] [Music] foreign 64.86 1.06 1.26 1.42 1.5 1.6 1.6 call 1.7 1.68 now to be fair what I'm going to do is I'm going to rotate the beam 180 degrees like this just in case there's some natural Bend in the beam I will take the average of the two numbers do it again [Music] 1.2.3 0.4 .5 so we'll call it maybe 1.6 as an average there might have been a little bit of residual bow there now we'll test the carbon black or the precursor same technique foreign let's go [Music] point three point six [Music] 1.6 1.58 and again we'll rotate it and take the average they're probably pretty straight we're getting pretty similar numbers each time I'm going to make sure this is super tight so it doesn't leak while we're measuring okay zero zero [Music] foreign so pretty much the same thing the carbon black didn't weaken it or strengthen it appreciably it's kind of in the noise so now Let's test the graphite this is 0.3 percent by weight all of these are by weight of graphite there we go oh zero it okay you'll see a little variation in the weight is simply by filling up the rod but if we started at zero it's really a bending modulus that we're measuring [Music] full stiffer 2.46 something like that foreign so the graphite did stiffen it a little bit let's see I didn't raise that quite enough okay okay zero okay here we go [Music] okay 1.54 pretty much the same they're pretty straight [Music] so we gained about 50 bending modulus stiffness from adding the graphite 0.3 percent maybe there's a little graphene in there let me show you what happens when we use 0.3 percent same mass loading of graphene good Center it all right let's see what we get [Music] it's definitely stiffer than the epoxy and it's stiffer than the graphene the graphite [Laughter] five 5.5 5.7 kilograms let's just do the other side just in case it's bowed and we're fooling ourselves here and do it again [Music] okay 3.2 4 .8 5.5 all six so we've gained about 400 percent [Music] in stiffness by adding point three percent one part in 300 of graphene now let's see what happens with 0.6 percent graphene right zeroed yep all right here we go [Music] foreign eight 10.2 we got to be fair I'd say that that is pretty legit this this graphene is freaking amazing okay let's go yeah eight nine ten eleven okay so by adding one part in 160 . we increased the bending modulus of the epoxy so 750 percent that's amazing this stuff really does work it's pretty good marzipan now what's interesting about this is the 0.3 percent Rod that I manufactured did take two batches of that graphene in order to make the mixture and for this Rod I had to do four batches in order to have enough that took a little bit of time but with graphene prices being five hundred dollars plus per gram time well spent and furthermore you can scale this up the most expensive part of this whole reaction was the capacitors and the scr switch and I'm only using them at about 20 to 25 percent of their maximum capacity you could quadruple the batch without buying anything else now if you did that don't do the most convenient thing which is to increase the diameter of the tube if you double the diameter you'll quadruple the batch the problem is you'll quadruple the volume but you'll only double the surface area which will slow the cooling and you'll get mostly graphite but if you lengthen the rods both the area and the volume go up the same so if you went to a four-time dose four times what we just did here you would go from 2 ohms to 8 Ohms on your resistance because you want the same compaction and if you want the same pulse duration you have to lower the capacitance four times and if you want to put four times the amount of energy into one-fourth of the capacitance you have to quadruple the voltage c v squared but you don't have to buy anything different you just rewire the capacitors for a different series and parallel setup and you're good to go this is useful an amateur could use this to build super epoxies and because the epoxy percentage is so or the additive percentage is so low it doesn't change the Radiology of the epoxy it mixes pores spreads and flows just like the pure stuff so you could add this to composite laminates that you're manufacturing and take advantage of the super high modulus of the of the epoxy now you could do this at home as an amateur you could do this as a small industrial setup but if you were going to be trying to produce graphene in the kilogram or ton volume or weight this is still a batch process and that does have some downsides what's interesting is that it was a recent paper published by a man named Islam from the Indian Institute of Technology Patna I'll put a link to both that paper that he wrote as well as The Rice Group paper in the description below the video the point is he came up with a method that produces very high quality graphene at orders of magnitude higher production rates than this and it's a continuous process that's scalable now like the ramen the equipment that they used is beyond us but just a little bit so stay tuned because we ain't done yet and if you like the kind of stuff that we're doing on this channel and the stuff that we're going to be doing please do me a huge favor and consider subscribing it really helps us out and a couple of years ago I never thought I would say this but I actually do believe now we're going to surpass a million subscribers and we may actually do that this year that would be absolutely fantastic and I'd appreciate it but it's also important because it drives the YouTube algorithms to distribute our videos to a broader audience and the more views the larger we get the more we can afford to do these projects take a lot of time and a fair amount of money to develop so I'd really appreciate it if you take a few seconds and subscribe in any case I want to thank you very much for watching stay safe have fun and I'll see you soon foreign [Music]

Channel: Tech Ingredients

Views: 1,789,473

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Id: 3hHoL77QDkg

Length: 55min 52sec (3352 seconds)

Published: Sat Mar 25 2023