Background of Nanocarbons Osawa Class No. 1 Thurs, May 28, 1:15‐2:05 pm (28 plates)
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Background of Nanocarbons
Osawa Class No. 1
Thurs, May 28, 1:15‐2:05 pm
(28 plates)
2
Overview of nanocarbons
• sp2
– Fullerenes• C60• Higher fullerenes
• Carbon nanotubes
• Multi‐shell fullerenes
– Amorphous
• sp3
– Nanodiamonds
１．Why nanocarbons?
Carbon was the most interesting element in chemistry.Flexibilities in valence, properties and shapes.Extensive applications well anticipated.Surprising discoveries of C60 (1985, 1990) and carbon nanotubes (1991) triggered feverish developmentsWhen will fullerene industry starts?
Indeed, novel forms of fullerenes including carbon nanotubes discovered
and at one time
fullerenes were considered the most promising material for nanotechnology.
Status quo of C60, CNT
• High production cost
• Health hazard possibility
• No outstanding applications found
Year Manuf. methodC60/C70 (80/20)
$/kg
1990
Arc discharge
>1,000,000
1993 100,000
1998 10,000
2001 Combustion 500
Transition of market price of C60/C70 mixture
Our contribution: soot, C60 and carbon nano‐onions are related
Commercial carbon black (pure soot)
Structure of soot was long a matter of dispute.
Furnace black
Rosalind Franklin Prof. S. Ohtani
Crick
Franklin
Wilkinson
Watson
200KeVelectron beam focused within TEMto 150A/cm2
Carbon black（soot）
15 min
spiral
Mostly onions, but・・・
2 nm
Ｓｐｉｒａｌ Ｏｎｉｏｎ
1. Onions are formed from spiral intermediates2. Conversion is reversible and involves self-
adjustment mechanism3. Stable nanao-onions are the final product
+
++
+
C60@C240@C540
C60@C240
C60
C60@C240@C540@C960
Spiro
id-o
nion
inte
rcon
vers
ion
Snow-accreting growth
Groth pathways of the primary particles of soot
13
Overview of nanocarbons
• sp2
– Fullerenes• C60• Higher fullerenes
• Carbon nanotubes
• Multi‐shell fullerenes
– Amorphous
• sp3
– Nanodiamonds
Nanodiamond
• We believe ‘single‐nano diamond’ particles are the final solution to the search of the most useful nanocarbon.
• The first nanocarbon comprised of sp3 carbon atoms. – This statement not rigorously correct.
• Diamond is the best industrial material on earth!
15
Partial list of diamond properties (natural bulk)
classification sub-class values notes
optical TransparencyRefractivity
UV-VIS-IRnD＝2.417
largesthigh
chemicalAcids-alkalis
Oxidation
Not attachedWithstands
supercritical water
inactiveHighly
resistant
electric Dielectric 5.5×1013 Ω・cm insulator
thermal Thermal cond.Specific heat
900-2000 W/m・K0.124 cal/Kg(25C)
largestvery small
materialistic Thermal expan.Young’s modul.
0.8×106/K1,050 GPa
smallestlargest
Major Artificial Diamondsmethod
（raw material）discovery(year)
Form of product（av size）
Country of production
Hydrostatic HPHT
（graphite + Fe + cat）
GE
（1955）Octahedral cubic crystallites（50μm）
China
Shock wave
（explosive, Cu powder + graphite）
DeCarli‐Jamieson
(1961)
Polycrystalline particles (50μm)
China, Japan
Detonation
(TNT+RDX/water)
Danilenko‐Volkov‐
Elin(1963)
Cubic single‐crystal
（4‐5 nm)
Japan
(Russia, China)*
CVD
（CH4 + H2 , C60 + Ar）Eversole(1950)
Polycrystalline films（thickness up to
μm)
[Japan, US] (under developmnt)
*Only agglutinates
17
CH3
NO2O 2N
NO2
NO2O2NN N
N
NO2
TNT
hexogen
CO2 or water
60% diamondsoot
40% amorphouscarbon
1963, Danilenko & Titov (Ukraine)
No carbon source other than carbon atoms in the explosive molecules used.
Yield 3‐5% based on theweight of explosives used.
An ideal material for nanotechnology!
Composition BA military explosive
Discovery of detonation nanodiamond
Stagnation1. First misfortune:
1963-1989 Kept secret in Soviet military regime.
Little progress.2. Second misfortune:
1989-2002 Structure mis-interpreted.
3. First breakthrough:2002 Agglutination recognized and agglutinates broken up into primary particles.
Commercial nanodiamond has been believed dispersed, but actually not.
19
Intensivesonication
No trace of primary particles!
Recognition of agglutinatin by DLS measurements of particle size distribution
SEM
Core agglutinates, 100-200 nm, cannot be disintegrated by any conventional methods.
20
Breakthrough Core agglutinates successfully disintegrated by wet beads‐milling to produce primary crystallites of detonation nanodiamond for the first time (2002).
Beads‐milling:
（１）High‐density beads packed in the milling room to 70‐80% of space.（２）Slurry of substrate particles in water supplied into milling space.（３）The closed mixture agitated at high speed (~4000 rpm).（４）Slurry separated from beads by centrifuge.
Microbeads: 30 μm ZrO2Slurry: 10% agglutinated nanodiamond in water
21
Beads‐Mill in operation at NCRI
Beads: 30μm ZrO2
Mill capacity: 160 mLUltraApex Mill type UAM‐015 Mfd by Kotobuki Ind. Co.,
22
Out‐going slurry
Cooling water
In‐coming slurry
Centrifugal separator
Milling cell in detail
23
Mechanism of beads-milling1. Almost weightless micro-beads
are given high kinetic energy by high-speed rotation.
2. Nano-sized particles pinched between the moving pair of micro-beads receive high impact at the collisional point to be crushed.
Larger by-products
24
Size and shapeTEM of monodisperse particles (re‐aggregated)
Size from three independent determinations : 4.8 ± 0.7 nm
Shape: irregular, most likely truncated octahedra
truncation
Octahedron(shape of natural diamond crystal
Trundcated octahedron(14‐faced)
25
method size, nm source
TEM 4.8±0.8 China
DLS 5.0±0.8 Japan
XRD 4.5±0.5 Russia
Average =
４.8 ± 0.7nm
1. Quite uniform in size.2. Size unchangeable by minor adjustments of
explosion conditions.
Size of SND
26
Stable colloid・・・for a wide range of pH
aggregates Monodisperse aggregates
pH=4.88
27
Core agglutinate (‘UDD’)
Primary particle(mdsn-D)
No. of grains 70,000～350,000 1
Size, nm 60-200 4-5
AqeousSuspension
stable, no precipitates, turbid, grey, no
gellation
stable, no precipitates, transparent colloid,
black, gellation from ca8%
DSC of aq. gel - non-freezing water layer
TGA - Explosive combustion at ca 500°C
Raman - D>>GSEM/TEM visible/assembly Invisible/dispersed
Terminology
(1) Detonation nanodiamond
200nm‐20μm Agglutinate/aggomerate(2) Primary particles of detonation nanodiamond or 5nm diamond particle
4.8±0.7 nmdispersed only in colloidal solution
aggregated in dried solid
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