of Nanodiamond Including of Single Nano Diamond...
Transcript of of Nanodiamond Including of Single Nano Diamond...
Handling of Nanodiamond Including Purification, Properties of Dispersed
Single‐Nano Diamond Particles
Osawa Class No. 2
Thurs, May 28, 2:15‐3:05 pm
(32 plates)
GEOMETRICAL AND ELECTRONIC STRUCTURE
SCC‐DFTB CalculationsCore‐Shell StructureSurface ChargePolarization Mechanism Unusually Strong Hydration
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Aqueous colloid Hard gel (water ca 20%)
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{111}
Diamond
Graphitic (Holey bucky‐onion)
Truncated octahedron
SCC‐DFTB
Self‐Consistent Charges Density Functional Theory on Tight Binding Approximation
Input (all diamond)
Output(core‐shell)
{100}
Barnard‐Sternberg 2007
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Barnard‐Sternberg 2007
1. Strong Mulliken charges on all the facets
2. {111} (‐), {100} (+), hence multi‐pole
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Carbon Fullerene diamondElectronagativity +++ ‐‐‐Acquired charge ‐ +
Reminds us of the high stability of 1‐adamantyl cationThere are almost infinite number of 1,3,5‐triaxial hyper‐conjugative stabilization
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Why {100} facets acquire large positive charge?
sp2 Graphehe shell
sp2+x Intermediate core
sp3 Diamond core
Space >0.335 nm
Spherical seamless model
Truncated octahedral holey bucky model
a
b
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Consequences of polarized diamond
1. Abnormally strong hydration2. Unprecedented agglutination3. Ligand exchange equilibrium
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-60 -40 -20 0 20 40
-40
-20
0Q
(mV)
T (oC)
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2
1. Aqueous gel of nanodiamond2. Aqueous gel of C60
Korobov 2007
DSC analysis of hydration shell (2007): thickness 0.6 nm, mass of water equal to 24% of the weight of an SNBD particle.
1. Abnormally strong hydration
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Three models for non‐freezing aqueous phase
a b
Nanocarbon particle
non‐freezing aqueous phase
Model A Model B Model C
micropore
nanopore
non‐freezing aqueous phase
SNBD ϕ4.8 nm
Surface‐adsorped water layer 1.0 nm thick
MH2O/MSNBD=0.47
Melting/freezing layer0.4 nm thick
Inner inert layer0.6 nm thickMIIL/MSNBD=0.22‐0.24
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Hydration shell on the surface of 5‐nm buckydiamond by seamless model
1. Water molecules are strongly absorbed onto the surface electrostatic field.
2. Orientations of water molecules differ depending on the sign of field.
3. Intercluster interactions are attractive.4. Facet‐controlled clusters of water stabilize the
hydration shell.
+ -
HHO H
HO
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TNT+RDX
Soot removal
Beads‐
milling
Evaporation of bulk water
Partial evaporation of nano‐phase water
Powder (Interfacial coherent and incoherent interfacial mixed aggregates)
Colloid
Soft gelHard gel
Redispersionby addiiton of water
Stable aqueous colloid of SND
Conc.wt%
Appearance
<約8% Transparent and light solution
8~(20) Soft gel
(20~(50) Hard gel
(50)~68 Narrow stripes or whisker crystal‐like solid
(): estimated
2. Unprecedented agglutination
It took more than 40 years to destroy agglutination
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• Early soot‐like model of agglutinates I
Spherical graphitic shell
Truncated octaheral core
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Model of SND: truncated octahedron
[100] square facets &[111] triangle or hexagonal facets are much different!
Barnard, 2007
Inter‐particle interactions probably governed by facet‐facet interactions, but not by DLVO theory alone
Electrostatic fields on the facets of truncated octahedral model
Facet ColorElectrostatic field
No. of equivalent facets
(100) ++ 6
(111)a ‐‐ 4
(111)b + 4
Front:Woodcraft model of truncated octahedronBack: Interfacial bonding of type {111}a/{111}b
+ electrostatic field
‐ electrostatic field intermediate electrostatic field
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A strong support for Barnard’s proposal:Formation of diamond whiskers from SND
Agglutinates: Size=70-200nm, coherent interfacial assembly of primary particles, impossible to completely disperse by any conventional methods but beads milling
Williams, 200724
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World market of detonation nanodiamond(tons, estd)
Mixed aggregatesPrimary particles
Country 2006 2007 2008Russia 0.8 2.0
8.0Ukraine 1.0 1.2
Byelorussia 0.05 0.06
China 1.0 1.2
Japan ‐ 0.1 0.3
Total 2.8 4.7 8.3
3. Ligand exchange equilibrium
Health risk
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Examination of cytotoxicity
• Yu et al.(2005)、Top‐down pulverized artificial diamond particles (100nm) exhibit weak toxicity to kidney cells.
• Nanocarbon samples tested5nm diamond particles (ND ), ND‐COOH, ND‐COONa 2‐10nNano‐sized carbon blacks (CB), faintly toxic, 20-30nm CdO, highly toxic, a few hundred nm
• CellsNeuroblastoma (neuronal phenotype)Macrophages (rat alvelar)Keratinocytes, PC‐12
• BioassayMTT*colorimetric method, to study damage on mitochondria membranesROS, to evaluate oxidation stress DCFH2+→DCF(fluorescent) **
CellTiter‐Glo luminescent activity assay kit
*3‐[4,5‐Dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide **2’,7’‐Dichlorohydrofluoresein
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A
Neuroblastoma・nanocarbon particles (1)
balance ND‐raw 100μg/ml ND‐COOH 100μg/ml
10μmCarbon black, 100μg/ml CdO 2.5μg/ml
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Balance ND‐raw 100μg/ml CB100μg/ml CdO 2.5μg/ml
Oregon Green Tublin
Rhodamine 123
The whole cell body and mitochondria are made fluorescent. Upon addition of nanocarbon particles, they are taken into cells and induce structural changes, but mitochondria membranes are not damaged. CdO destroys mitochondria.
Neuroblastoma ・nanocarbon particles (2)
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After contact of 25μl/ml raw ND with neuroblastoma for 24h, ND particles penetrates
into cell through cell wall and aggregate.
500nm100nm
Neuroblastoma cells grow even on a collagen substrate pasted with ND‐COOH layer
3210μm 10μm
No ND‐COOH With ND‐COOH