Carbon Nanotechnology .pdf

Carbon Nanomaterials

1. 1Dr P. Justin, RGUKT-RK Valley, Kadapa.

2. Dr P. Justin, RGUKT-RK Valley, Kadapa. 2

3. 3
Carbonisthemainelement,andtheyexistintheformofellipsoids,hollowspheres,and
tubes.Graphiteanddiamondareallotropesofthemostabundantelement,carbon.
It exists in all four dimensions of nanomaterials (i.e., 3D diamond and graphite, 2D graphite
sheets, nanotubes in 1D, and fullerene in zero-dimension)..
Dr P. Justin, RGUKT-RK Valley, Kadapa.
Thestructuralconfigurationandhybridizationstatesofcarbonstronglyinfluencethe
electronic,physical,andchemicalbehaviorofthenanomaterial.Carbonhassixelectrons,
anditsgroundstateconfigurationis1s
2
2s
2
2p
2
.
Carboncanbeinsp,sp
2
,andsp
3
hybridizedstatesinceithasalowenergygapamong2s,
and2pallowselectrontransitionofitsneighbouringcarbonatom.Thebondangleforsp,sp
2
andsp
3
hybridizedcarbonis180°,120°and109.5°,respectively.Andthecorresponding
geometryisLinear,TrigonalplanarandTetrahedral.
Inthecaseofsphybridizedcarbonatoms,thecovalentbondingwithneighbouratomsat
higherenergylevelsprovidesenergytocompensateforthisconfiguration,whichisthesame
forsp
2
andsp
3
hybridization.Theunhybridp-orbitalsconsiderπ-bondingamongthemselves.
Thepromisingtrigonometricsp3configurationexistsforadiamondathighpressuresand
temperatures.Withthedecreaseintheheatformation,theplanarsp2configurationaddsup,
thusformingasingle-layeredsheetstructurewithsingleπ-bondandthree-sigmacovalent
bonding.

4. 4Dr P. Justin, RGUKT-RK Valley, Kadapa.
Slightshearforcesand
chemical-physical separation
inducesweakinterplanarforces
amonggraphenesheetsand
inducesslip-upsamongthem

5. 5
Mostofthenanomaterialsareunique,donotexistinnatureandaretruly“man-made”
relativelyrecently.SumioIijimaisaJapanesephysicistandinventorwhowasthefirstto
describecarbonnanotubes'formationclearly.
Usinganelectronmicroscope,in1991hediscoveredcarbonnanotubes(electronmicroscopic
marvel),afourth-allotropecarbonsolidthatbecameafocusofinternationalattention.Carbon-
basednanomaterialsincludefullerenes,carbonnanotubes,grapheneanditsderivatives,
grapheneoxide,nanodiamonds,andcarbon-basedquantumdots.
Carbon is the fourth most prevalent element in the universe, and it exists in a variety of
forms known as allotropes, depending on how carbon atoms are arranged. Polymorphic transition
is a reversible transition of a solid crystalline phase at a certain temperature and pressure to
another phase of the same chemical composition with a different crystal structure.
Dr P. Justin, RGUKT-RK Valley, Kadapa.

6. 6Dr P. Justin, RGUKT-RK Valley, Kadapa.

7. 7Dr P. Justin, RGUKT-RK Valley, Kadapa.

8. 8
In materials science, the ability of a solid material (except elemental solids) to exist in more
than one form or crystal structure is called polymorphism. Polymorphism is a form of isomerism.
In materials science, the ability of a elemental solid material (not compound) to exist in more
than one form or crystal structure is called allotropy.
Polymorphictransitionisareversibletransitionofasolidcrystallinephaseatacertain
temperatureandpressuretoanotherphaseofthesamechemicalcompositionwithadifferent
crystalstructure.

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Dr P. Justin, RGUKT-RK Valley, Kadapa.

9. 9
PureironismagneticandhasaBCCcrystalstructureatroomtemperature,which
changestoFCC(austenite,whichisnonmagnetic)ironat912°C(1674°F).
Dr P. Justin, RGUKT-RK Valley, Kadapa.

10. 10Dr P. Justin, RGUKT-RK Valley, Kadapa.

11. 11Dr P. Justin, RGUKT-RK Valley, Kadapa.

12. 12
Ingraphite,eachcarbonatomisattached
totwoothercarbonatomswithsinglebond
(sp2hybrid,strongcovalent)andthirdone
withdoublebonddelocalized(i.e.,doesnot
belongtoaspecificatomorbondi.e.,free
electron)inaregularhexagonalfashion.
This hexagonal arrangement gives two
dimensional sheets arranged parallel to each
other (spacing is 0.335 nm) and linked via weak
vanderwalls interaction. This arrangement and
parallel sheet structure make graphite soft,
good conductor of electricity because of free
electrons from pi-bond and slippery to touch.
In each layer is arranged in the honey
comb lattice and it is highly anisotropic. In
oxygen containing atmospheres, the graphite
readily converted into carbon dioxide at
temperatures of 700oC and above. It is
diamagnetic.
Dr P. Justin, RGUKT-RK Valley, Kadapa.

13. 13
Graphite and diamond have comparable free energies (=-3kJ/mol), yet forming diamond from
graphite is far from easy. However, it’s the kinetic aspect (activation energy or Ea) of this
process that screws this up ( higher activation energy or Ea)
So compare to the small energy gap of the process, lots of energy is needed to overcome the
Eahill which is why you needs high pressure and temperature (12 Giga Pascal's and 1700K ) with
precise control to turn graphite into diamond.
To form diamond, the hexagonal rings in graphite first have to deform. Khaliullinand co (Ref:
arxiv.org/abs/1101.1406)show that at low pressures, below 10GPa, the hexagonal rings in
graphite tend to form the boat-shaped structure. When this happens, the graphite forms into a
metastable allotrope of carbon called hexagonal diamond.
Dr P. Justin, RGUKT-RK Valley, Kadapa.

14. 14Dr P. Justin, RGUKT-RK Valley, Kadapa.

15. 15
1.J.Park,T.S.Sudarshan“ChemicalVaporDeposition(Surface
EngineeringSeries,Vol2)”,ASMInternational®MaterialsPark,2001.
2.Jong-HeePark,T.S.Sudarshan“ChemicalVaporDeposition(Surface
EngineeringSeries,Vol2)”,ASMInternational®MaterialsPark,2001.
3.L.Murr,“IndustrialMaterialsScienceandEngineering”MarcelDekkerInc.,
1984.
4. WilliamD.CallisterJr.,DavidG.Rethwisch,“Fundamentalsof
MaterialsScienceandEngineering:AnIntegratedApproach”,5thedition,Wiley,
2018.
5. Fromwebsiteslikegoogle,wikipedia,researchgate,etc
References
Dr P. Justin, RGUKT-RK Valley, Kadapa.

16. 1Dr P. Justin, RGUKT-RK Valley, Kadapa.

17. 2
Ascivilizationprogressed,naturaldiamondsdiminishedintheearth'scrustdueto
exhaustedmining,whichledtomuchresearchontheartificialsynthesisofdiamonds.
Scientistssuccessfullysynthesizedcrystallinediamondsinthe1950susingultra-highpressure,
requiringuniqueandexpensiveequipment.
Asaresult,moreresearchontheinexpensiveandlarge-scaleproductiontechniqueofdiamonds
increasedtremendously.Atthebeginningofthe1970swhenresearchersdiscoveredthatdiamond
crystalscouldbegrownasthincoatingsatlowdepositionpressures(10
2
-10
3
Pa)fromhydrocarbongas
orcarbonvapour(gaseousphase)diamondbychemicalvapourdeposition(CVD).
Dr P. Justin, RGUKT-RK Valley, Kadapa.
NanocrystallinediamondorDiamond-likecarbon(DLC)wasdiscoveredaccidentallyduring
researchonthevapour-phasesynthesisofadiamondbyAisenbergetal.in1971.Fromthis
accidentdiscoveryonwards,overwhelminginteresthasgrowningeneratingandusinghigh-quality
diamondcoatingsovermetallicandceramicsubstratesforvariousmechanical,electronic,
optical,andtribologicalapplications.
Propertiesthatmakediamondcoatingsveryattractiveforsuchapplicationsinclude
exceptionallyhighmechanicalhardness,ultralowfrictionandwearcoefficients,excellent
thermalconductivity,minimumthermalexpansionandexcellentchemicalinertnessandhigh
corrosionresistance.Combiningtheseexceptionalqualitiesinonematerialisscarceandmakesit
idealfornumerousindustrialapplications.

18. 3
Diamondisanallotropeofcarboninwhichthecarbonatomsarearranged
inadiamondcubiccrystallattice,anditisalsothemostpopulargemstone.
They are made of nearly 100% carbon atoms and are so durable that the
only other mineral that can scratch a diamond's surface is another diamond.
The diamond boasts the highest thermal conductivity and hardness of
all naturally occurring materials. High electrical resistivity.
Inacubicdiamondstructure,allatomicsitesareoccupiedbytwoidenticalcarbonatomsinthe
conventionalfcccrystallattice.Inthisstructure,oneofthesublatticesisshiftedalongthebody
diagonalofthecubiccellbyone-quarter(1/4)ofthelengthofthediagonali.e.,anextraatomis
placedat¼a
1+¼a
2+¼a
3fromeachofthefccatoms.
Thisarrangementleadstotheformationtetrahedralstructurewherefourequal-distanced
neighbouringcarbonatoms(NNs)surroundeachcarbonatom,asshowninthefigure.Thebasic
elementofthestructureisatetrahedronwhereeachcarbonatomisatthecentre,anditsfour
NNsareatthecornersofthecube(orviceversa).
Dr P. Justin, RGUKT-RK Valley, Kadapa.

19. 4
Each atom forms four bonds with its NNs. Atoms in diamond-type crystals form covalent
bonding. The bonding energy is associated with the shared valence electrons between atoms and
depends on the relative orientation of atoms.
Semiconductorssuchasdiamond(C),silicon(Si),germaniumandgreytin(α-Sn)crystallizein
thediamondcubicstructure.
Theatomicarrangementinthediamondstructurehelps
explainitsmechanical,chemical,andmetallurgical
properties.Thesesemiconductorcrystalscanbecleaved
alongcertainatomicplanestoproduceexcellentplanar
surfaces,e.g.,diamondsusedinjewelry.Suchsurfaces
areusedasFabry–Pérotreflectorsinsemiconductor
lasers.Chemicalreactionsperformedwithsuchcrystals,
suchasetching,oftenoccurpreferentiallyincertain
directions.
Dr P. Justin, RGUKT-RK Valley, Kadapa.

20. 5
 Eachcarbonatomhasundergonesp3
hybridizationsothatitbonds(tetrahedral)to
fourothercarbons;theseareextremelystrong
covalentbondwithlength0.155nmandbond
angle109,5
o
.Itisastrong,rigidthree-
dimensionalstructurethatresultsinaninfinite
networkofatoms.Totalnumberofatomsin
diamondcubicstructureis8.
 Thisaccountsfordiamond'shardness,
extraordinarystrengthanddurabilityandgives
diamondahigherdensitythangraphite(3.514
gramspercubiccentimeter).Sinceeach
electronsofCisincludedinsinglebondsothere
isnofreeelectronavailableandhencediamond
isbadconductorofelectricity
Dr P. Justin, RGUKT-RK Valley, Kadapa.

21. Dr P. Justin, RGUKT-RK Valley, Kadapa. 6

22. Dr P. Justin, RGUKT-RK Valley, Kadapa. 7
https://www.debeers.com/en-us/home
₹88,69,072.50
₹3,60,000
₹9,000

23. Dr P. Justin, RGUKT-RK Valley, Kadapa. 8

24. Dr P. Justin, RGUKT-RK Valley, Kadapa. 9

25. Dr P. Justin, RGUKT-RK Valley, Kadapa. 10
ThemethodsforproducingDLCbyexposingathebasematerialtoglowdischarge
plasmaofahydrocarbongaslikeAcetylene(C
2H
2)ormethane(CH
4).
Themajormethodsforgeneratingglowdischargeindecompressedgasincludes
theDCdischargeandRFdischargemethods.
Manyofthemapplythehigh-frequencypoweroranegativeDCvoltagetothebase
material,whichisthecathode,andthecounteranodeiskeptatthegroundpotential.

26. Dr P. Justin, RGUKT-RK Valley, Kadapa. 11

27. Dr P. Justin, RGUKT-RK Valley, Kadapa. 12

28. Dr P. Justin, RGUKT-RK Valley, Kadapa. 13

29. Dr P. Justin, RGUKT-RK Valley, Kadapa. 14

30. Dr P. Justin, RGUKT-RK Valley, Kadapa. 15

31. Dr P. Justin, RGUKT-RK Valley, Kadapa. 16

32. Dr P. Justin, RGUKT-RK Valley, Kadapa. 17
DomecoatedwithDLCfor
opticalandtribologicalpurposes
ACo-alloyvalvepartfromaproducing
oilwell(30mmdiameter),coatedon
therightsidewithta-C,inorderto
testforaddedresistancetochemical
andabrasivedegradationinthe
workingenvironment.
ACo-alloyvalvepartfromaproducing
oilwell(30mmdiameter),coatedon
therightsidewithta-C,inorderto
testforaddedresistancetochemical
andabrasivedegradationinthe
workingenvironment.

33. Dr P. Justin, RGUKT-RK Valley, Kadapa. 18

34. Dr P. Justin, RGUKT-RK Valley, Kadapa. 19

35. Dr P. Justin, RGUKT-RK Valley, Kadapa. 20
Anyapplicationexploitingdiamondpropertiesinathinfilmconfigurationcouldprofitfrom
integratingnanocrystallinediamonds.Thisisespeciallyapparentinpassiveapplications
suchasheatspreading,tribology,opticalcoatingsetc.
Duetoitsextremehardness,diamondhaslongbeenusedforcutting,drilling,miningand
millingeverythingfromthehardestrocktothesoftestaluminium.Diamond-likefilmsexhibit
relativelygoodwearresistance,abrasiveresistance,andslidingcoefficientoffriction.
Thesepropertieshelpitfindapplicationsinthebearingindustry(evenforwindturbineshaft
bearings)andinthosemachinecomponentswhererelativeslidingisinvolved.Bearingscoated
withthesefilmswillbesilentinoperationduetolessfriction.
Thisalsomeansthatthelifeofthebearingcanbeincreased,therebyreducingthe
runningcostofthemachineImprovementinScratchresistancebyafactorof6hasbeen
obtainedforplasticlensescoatedwiththesefilms.

36. Dr P. Justin, RGUKT-RK Valley, Kadapa. 21

37. Dr P. Justin, RGUKT-RK Valley, Kadapa. 22
Thereareanincreasingnumberofapplicationsthatrequireamaterialwithhighthermal
conductivity,aswellashighstrengthandminimumweight.Aerospaceapplicationsinclude,jet
engineandgearsystem,heatexchangersinhypersonicvehiclesoperatingoverawide
temperaturerangeof20-930°C,coolingfansinspacepowersystemsoperatingupto780°C.
Thepropertiesofthesefilmslikegoodsurfacehardness,excellentwearresistance,chemical
inertnessandenvironmentdurabilitycanbeputtogooduseintheautomobilesindustry.
Thedevelopmentofdiamond-likecoatingspecificallyforautomotivepolymersseemsto
offergreatpromiseandcouldincreasetheuseoflowcostpolymermaterial.Whenplastic
issubstitutedforheaviermaterial,thevehicleweightisreducedandthistranslates
directlyintoenergysavingthroughreducedfuelconsumption.

38. Dr P. Justin, RGUKT-RK Valley, Kadapa. 23
Diamondhaspotentialapplicationsashumanimplantcoatingsbecausetheyfulfiltheprimary
requisitesforuseinhumanimplants:biocompatibilityandchemicalstability.Diamondcoatings
havebeendepositedonsurgicallyimplantablesubstratessuchasceramicsusedindental
implants,stainlesssteel,titaniumandmolybdenumusedforprostheticdevices,etc..
Diamondcoatingshavebeendepositedonsurgicallyimplantablesubstratessuchasceramics
usedindentalimplants,stainlesssteel,titaniumandmolybdenumusedforprostheticdevices,
etc.

39. Dr P. Justin, RGUKT-RK Valley, Kadapa. 24
Thediamondfilmsareusedasdielectriclayersforthermalmanagementsystems.Inthis
case,theNCDfilmiscoatedoncopperinsertsusedasheattransferdevicesinmultichip.For
example,thehigh-performancemultichipmodulesinvolvepowerdensitylevelsthataredifficult
tocopewithusingconventionalpackagingmaterials.
RecentlyacompositeCVDdiamond-siliconheatspreaderhasbeendemonstratedtohave
superiorpropertiesataproductioncostcomparabletothatofthetraditionalmaterialslikeAlN
andCuW.Recently,NCDcoatinghasbeendemonstratedtoleadtoanincreaseintheelectron
emissionofmolybdenumemitters.
Borondopingleadstoptypesemiconductingdiamond,andalthoughntypedopinghasprovedto
beelusive,anumberofprototypeelectronicdeviceshavebeendemonstratedusingNCD
diamond,suchasthermistors,fieldeffecttransistors,Schottkeydiodes,fieldemissionarrays.
Thehighestthermalconductivitycombinedwiththehighestelasticconstantmake
diamondusefulinsurfaceacousticwavedevicesforhigh-frequencyoperationsand
telecommunication.DiamondbasedSAWthedevicehastheedgeoverothermaterials
sinceitcanbeoperatedathigherfrequencieswhichmeansthatmoreinformationcanbe
transmitted.

40. Dr P. Justin, RGUKT-RK Valley, Kadapa. 25
Duetoitstransparencytoawiderangeofwavelengthsfromtheinfraredtotheultraviolet
regionandevenx-rayscombinedtogetherwithlowatomicnumber,radiationhardnessand
mechanicalsturdiness,diamondisanidealchoiceasaprotectivewindowmaterialforlasers,X-
raysources,etc.
Thesefilmsarescratch/chemicalresistantandblockultravioletradiation.Theseproperties,
takentogether,canrevolutionizethespectacleandmedicalprotectivegoggleindustry.
Improvementinscratchresistancebyafactorof6hasbeenobtainedforplasticlensescoated
withthesefilms.
Theprotectiveovercoatincreasesthelifeofmanyotherpotentiallyvaluablecoatingsin
differentapplications,forexample,thesoftIndium-TinOxidefilmusedinphotovoltaic
applications,softYBaCu
2O
3superconductingthinfilms,providedthediamond-likeovercoatdoes
notalterorinfluencethebasicpropertiesoftheunderlyingsoftcoating.
NCDfilmswithprecisecontroloverrefractiveindexandthicknessalsohavebeendepositedon
siliconsolarcellsasantireflectioncoatingsincreasingincellefficiencyby40%andongermanium
windowsastransparentprotectivecoatings.
Thesmoothandwear-resistantNCDcoatingshavebeenshowntoprovideexcellent
protectiontodiscsforuseasmagneticrecordingmediawithoutaffectingtheinherent
propertiesofthemagneticmaterial.TheNCDcoatingontherecordingheadcanprevent
wearofthemagneticlayerandsubsequentdataloss.
ThehighfilmhardnessandhighchemicalinertnessmakesNCDfilmsmoresuitableas
passivationlayersforsensordevicesascomparedtoothermaterials,suchasSi
3N
4andSiO
2.

41. 26
1.J.Park,T.S.Sudarshan“ChemicalVaporDeposition(Surface
EngineeringSeries,Vol2)”,ASMInternational®MaterialsPark,2001.
2.Jong-HeePark,T.S.Sudarshan“ChemicalVaporDeposition(Surface
EngineeringSeries,Vol2)”,ASMInternational®MaterialsPark,2001.
3.L.Murr,“IndustrialMaterialsScienceandEngineering”MarcelDekkerInc.,
1984.
4. WilliamD.CallisterJr.,DavidG.Rethwisch,“Fundamentalsof
MaterialsScienceandEngineering:AnIntegratedApproach”,5thedition,Wiley,
2018.
5. Fromwebsiteslikegoogle,wikipedia,researchgate,etc
References
Dr P. Justin, RGUKT-RK Valley, Kadapa.

42. 1Dr P. Justin, RGUKT-RK Valley, Kadapa.

43. 2
Carbonnanotubes(CNTs)consistofasinglesheetofgraphite(i.e.,graphene)rolledintoa
cylindricaltubeandarechemicallybondedwithsp
2
bonds-powerfulformofmolecular
interaction.
Eachnanotubeisasinglemoleculecomposedofmillionsofatoms;thelengthofthismolecule
ismuchgreater(ontheorderofthousandsoftimesgreater)thanitsdiameter.Multiple-walled
carbonnanotubes(MWCNTs)consistingofconcentriccylindersalsoexist.

44. 3Dr P. Justin, RGUKT-RK Valley, Kadapa.

45. Dr P. Justin, RGUKT-RK Valley, Kadapa. 4
CNTsaresynthesizedbythethermalCVDmethodusinghydrocarbongasasacarbonsource.
Inthismethod,aquartztubeisplacedinsideafurnacemaintainedatahightemperature(500–
900°C)andheatedbyanRFheaterforaspecifiedtime.
Acruciblecontainingthesubstratecoatedwithcatalystnanoparticlesisplacedinsideaquartz
tubefilledwithinertgas.
Theexperimentalsetupisshownbelow.

46. Dr P. Justin, RGUKT-RK Valley, Kadapa. 5
Zeolite(Sodiumaluminiumsilicate)
Types of CVD
Name Heating Source
Thermal-
activated CVD
IR radiation, RF
heater, etc.
Photo Assisted
CVD
Arc lamps, CO
2laser,
Argon ion laser, Nd:
YAG laser, etc.
Plasma-assisted
CVD
microwave radiation,
etc.
Thermally Activated Chemical VapourDeposition
(CVD) Growth of Single-Walled Carbon Nanotubes
(SWCNTs)
Carbon
Sources
Hydrocarbongasessuchasacetylene,
ethylene,methane,etc.
SubstrateSubstratesarematerialsonwhichthe
CNTSaregrown—Zeolite,Silica,Silicon
platecoatedwithironparticles,etc.
Catalyst Iron,cobalt,nickel,molybdenum,iron-
molybdenumalloys,etc.
Heating
Source
RFHeater
Conditions
Temperature 500–900°C
Inert gas Argon

47. 6Dr P. Justin, RGUKT-RK Valley, Kadapa.

48. 7
Nanotubesareextremelystrongandstiffandrelativelyductile.Thetensilestrengthof
carbonnanotubesisapproximately100timesgreaterthanthatofsteelofthesamediameter
i.e.,oneofthestrongestknownmaterials(tensilestrengthsrangebetween13and53GPa)-
Grapheneisstrongest.CNTis100timesstrongerthanstainlesssteelandsixtimeslighter.
The first is the strength provided by the interlocking carbon-to-carbon covalent bonds. The
second is the fact that each carbon nanotube is one large molecule (made-up of millions of
atoms)
Since each carbon atom has four electrons in the outer shell and only three are used to form
covalent bonds, there is one remaining electron that is highly mobile (free electron) and available
for electrical conduction. As a consequence, both CNT and graphene are highly conductive.
Carbonnanotubesareveryinterestingmaterialsforelectricalengineeringapplicationsasthey
haveallthecharacteristicsofaperfectelectricalconductor,veryhighconductivity,current
carryingcapacity,strength,andthermalconductivity,allcombinedwithverylowweight.
The current-carrying capacity of CNT is 1000 times higher than that of copper. CNT can be
metallic or semiconducting, depending on their diameter and chirality. In the semiconducting
state they may be used for transistors and diodes.
Furthermore, nanotubes are excellent electric field emitters. As such, they can be used
for flat-screen displays (e.g., television screens and computer monitors).

49. 8
The current-carrying capacity of CNT is 1000 times higher than that of copper. CNT can be
metallic or semiconducting, depending on their diameter and chirality. In the semiconducting
state they may be used for transistors and diodes.
Furthermore, nanotubes are excellent electric field emitters. As such, they can be used
for flat-screen displays (e.g., television screens and computer monitors).

50. 9Dr P. Justin, RGUKT-RK Valley, Kadapa.

51. 10Dr P. Justin, RGUKT-RK Valley, Kadapa.

52. 11
Graphene,thenewestmemberofthenanocarbons,isasingleatomiclayerofgraphite,
composedofhexagonallysp
2
bondedcarbonatoms.Thesebondsareextremelystrong,yet
flexible,whichallowsthesheetstobend.Itisabout200timesstrongerthansteelitCanStop
aSpeedingBullet.
The first graphene material was produced by peeling apart a piece of graphite, layer by layer
using plastic adhesive tape until only a single layer of carbon remained.

53. 12
Two characteristics of graphene make it an exceptional material. First is the perfect order
found in its sheets—no atomic defects such as vacancies exist; also, these sheets are extremely
pure—only carbon atoms are present.
The second characteristic relates to the nature of the unbondedelectrons: at room
temperature, they move much faster than conducting electrons in ordinary metals and
semiconducting materials.
Intermsofitsproperties,graphenecouldbelabeledtheultimatematerial.Itisthe
strongestknownmaterial(~130GPa),thebestthermalconductor(~5000W/m∙K),andhasthe
lowestelectricalresistivity(10
−8
Ω∙m)—thatisthebestelectricalconductor.Furthermore,itis
transparent,chemicallyinert,andhasamodulusofelasticitycomparabletotheother
nanocarbons(~1TPa).

54. 13

55. 14

56. 15

57. 16
1.Take69mLof9:1mixtureofconcH
2SO
4/H
3PO
4(62.1:6.9mL)ina
250mLbeaker.(ThebathwaspreparedbyaddingH
2SO
4tothe
H
3PO
4slowlyandthoroughlymixingalmost60min.)
2.Tothisaddgraphiteflakes(3.00g)followedbyNaNO
3(1.5g)very
slowlywithmagneticstirring.
3.Nowcooltheresultingmixtureusinganicebathto<10°C
4.After60minofstirring,addKMnO
4(9.00g)veryslowlyand
maintainthereactiontemperaturebelow20°C(~2h).
5.Heatthewholemixture~35
o
Candstirredfor7h.(Themixture
turnedgreenduetotheformationoftheoxidizingagentMnO
3
+
)
6.After7hthegreencolorofMnO
3
+
wasdiminished,indicating
thattheoxidizingagentwasconsumed.
7.NowaddadditionalKMnO
4(9.00g)totheabovesolutions
andmaintainthereactionmixtureat~35
o
Cfor12h.
8.Add120mLofdistilledwatertotheabovereactionmixture
andmaintainthereactionmixtureat~90
o
Cfor30min.

58. 17
13.FinallyGOunderwentpurificationwithethanol(2times)andcollect
theGOfromcentrifugetubebyusingethanolandtransferto250mL
beaker.
14.Measurethewholemixtureandtakeexactly1/10
th
ofGOwith
ethanolintopettydishes.Theobtainedsolidmaterialswerekeptinthe
ovenat50
o
Cforfivedays&taketheweight.
15.RemainingGOtransfertoemptyethanolcontainerandstorein
freezerforfurtherapplications.
9.ThereactionwascooledtoRTandpouredontoice(400mL)with30%
H
2O
2(6-12mLoruntilthepurpleKMnO
4colordisappeared).
10.UponadditionoftheH
2O
2themixtureturnedlight-yellow.
11.After20minofswirling,themixtureunderwentcentrifugation,decanting
andpurified.
12.Thegraphiteoxidewaswashedandcentrifugedwith20%HCl(2times,
~200mL)anddistilledwater(minimum3times)sequentiallyuntilthepH
levelwas7.

59. 18

60. 19
Afullereneisanallotropeofcarbonwhosemoleculeconsistsoflargenumberofcarbon
atomsconnectedtoformbothhexagonal(six-carbonatom)andpentagonal(five-carbonatom)
geometricalconfigurationswithsingleanddoublebondssoastoformaclosedorpartially
closedmeshi.e.,cuboidstructure.
BuckminsterfullereneisatypeofC60moleculesfullereneconsistof20hexagonsand12
pentagons,whicharearrayedsuchthatnotwopentagonsshareacommonside;themolecular
surfacethusexhibitsthesymmetryofasoccerball(Truncatedisohedron).Namedinhonorof
R.BuckminsterFuller(1985),whoinventedthegeodesicdome;eachC60issimplyamolecular
replicaofsuchadome.
But,thesmallestbuckyballclusterisC20.Itistheunsaturatedversionofthe
dodecahedrane.Thefullerenesthatarelargerindiameterthanthenanotubeandhavingwalls
ofdifferentthicknessaremegatubes.
Uses and potential applications of fullerenes include
antioxidants in personal care products, biopharmaceuticals,
catalysts, organic solar cells, long-life batteries, high-
temperature superconductors, and molecular magnets.

61. 20

62. 21
1.J.Park,T.S.Sudarshan“ChemicalVaporDeposition(Surface
EngineeringSeries,Vol2)”,ASMInternational®MaterialsPark,2001.
2.Jong-HeePark,T.S.Sudarshan“ChemicalVaporDeposition(Surface
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