module 5 composites and macroscopic assemblies of … · module 5 composites and macroscopic...
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1
Module 5Composites
and macroscopic assemblies
of nanotubes
1/ Processing (Milo Shaffer)
2/ Characterization
3/ Properties (Jack Fischer)
Pascale Launois
Laboratoire de Physique des Solides, Orsay, France
[email protected]://www.lps.u-psud.fr/Utilisateurs/launois/
2
Nanotube (NT) compositesMaterials including a small fraction of NTs
Materials comprised mostly of NTs
Questions
● Homogeneity?
● NT rate, composition?
● NT structural parameters?
● Matrix characteristics?
● Adhesion between NTs and matrix?
● Alignment?
Morphology and structure:
Tools
● Transmission Electron Microscopy (TEM)
● Scanning Electron Microscopy (SEM)
● Optical imaging
● Thermal analysis
● Raman scattering
● X-ray and neutron scattering
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I. Rapid overview of the use of TEM, SEM, optical imaging or thermal analysis
II. X-ray and neutron diffraction
III. Raman spectroscopy
IV. Conclusion
Complementarity, advantages and disadvantages of the different methods
Lecture’s scheme
4
A few photographs…
Single Walled NT (SWNT) / polyvinyl alcohol (PVA)fiber
Mechanical propertiesP. Miaudet, S. Badaire, M. Maugey, A. Derré, V. Pichot,
P. Launois, P. Poulin and C. Zakri, Nanoletters 5, 2212 (2005)
Multi Walled NT(MWNT)
sheet
Transparentand
conductive
M. Zhang, S. Fang, A.A. Zakhidov, S.B. Lee,A.E. Aliev, C.D. Williams,K.R. Atkinson and R.H. Baughman,
Science 309, 1215 (2005)
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from A.V. Neimark, S. Ruetsch,K.G. Kornev, P.I. Ravikovitch,P. Poulin, S. Badaire and M. Maugey,Nano Letters 3, 419 (2003) Hierarchical
morphology
Single Walled NT (SWNT) / polyvinyl alcohol (PVA) fiberPVA = [ -CH2CHOH- ]n
Scanning Electron Microscopy
6
Composite films of MWNTs and polyaniline
PAn =
Nanoporous networkof PAn coated MWNTs
M. Wu, G.A. Snook, V. Gupta, M. Shaffer, D.J. Frayand G.Z. Chen, J. Mater. Chem. 15, 2297 (2005)
SEM images
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MWNT carpet : - preferential alignment of NTs- base-growth mechanism
M. Pinault, V. Pichot, H. Khodja, P. Launois,C. Reynaud and M. Mayne-L’Hermite,Nanoletters 5, 2394 (2005)
M. Zhang, S. Fang, A.A Zakhidov, S.B. Lee, A.E. Aliev, C.D. Williams, K.R. Atkinson andR.H. Baughman, Science 309, 1215 (2005)
MWNT carpet conversion into sheets
SEM images
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+ Transmission Electron Microscopy
SEM HRTEM
SWNT strandB. Wei, R. Vajtai, Y.Y. Choi, P.M. Ajayan, H. Zhu, C. Xu and D. Wu,
Nano Letters 2, 1105 (2002)
Morphology
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SEM
HRTEM
Polypyrrole/MWNT compositePpy: Polypyrrole
Coaxially tubular structuresin composite
n
T.-M. Wu and S.-H. Lin, J. of Polymer Science: Part B, 44, 1413 (2006)
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Optical micrographs between crossed polarizers
Morphology ofSWNT-PE composite
PE=polyethylene[CH2=CH2]n
Birefringence
From large PE spherulites in pure PEto smaller crystallites in the composite
R. Haggenmueller, J.E. Fischer and K.I. Winey,
Macromolecules 39, 2964 (2006)
1mm
NT alignment in SWNT-PVA ribbonPVA= polyvinyl alcohol
[-CH2CHOH- ]n
Absorptionfl preferential
orientation of the NTs
P. Poulin, B. Vigolo and P. Launois, Carbon 40, 1741 (2002)
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Thermal analysis
SWNT/PVA fiberFrom S. Badaire PhD thesis, Bordeaux, France (2004)
Thermo-Gravimetric AnalysisM
ass
loss
(mg)
Signal derivative (m
g/°C)
Temperature (°C)
50 wt %
Loss of PVA
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Ø Morphology: homogeneity, nanoporous network, hierarchical morphology, alignment…on the examples of SWNT strands, MWNT/PAn films and SWNT/PVA fibers, MWNT carpets
Ø NT alignment – qualitative results
Ø Polymer/NT interactions: coaxial tubular structures, polymer crystallization…on the examples of MWNT/Ppy and SWNT/PE composites
Ø Composition
Part I summary
SEM, TEM, optical imaging and thermal analysis fi complementary results
Dramatic change in length-scales involved, from macroscopic to nanoscopic components:
complementary analyses at different scales have to be performed
Spatial resolutionOptical microscopy ~μm(polarization)SEM ≥10 nm TEM ≤ nm
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I. Rapid overview of the use of TEM, SEM, optical imaging or thermal analysis
II. X-ray and neutron diffraction
1. Theory 2. Graphite and turbostratic carbon 3. Multi Walled Nanotube powders4. Single Walled Nanotube powders5. Oriented nanotubes6. Composites: the other components
III. Raman spectroscopy
IV. Conclusion
Lecture’s scheme
14
Q = kf - ki
λ~Å
X-rays:
re=2.8 fm (« classical radius » of the electron)
Neutrons: fC=6.65 fm
Q= 4πsin(θ)λ
2θ2θ
2θ ki= kf=(2π)/λ
X-rays neutrons
Smaller Higher Qsamples
(higher flux)
Elastic scattering by one atom
II.1. Theory
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Scattering by an assembly of atoms: interferences
I(Q) ∝ < Σ fj(Q) ei Q r >j2
atoms j
Direct space
Crystal lattice (a1, a2, a3)
Reciprocal space
Reciprocal lattice (a1*, a2*, a3*)
a1*=2π ___________
Family of parallel lattice planes: Miller indices (h,k,l), defined as the
coordinates of the shortest reciprocal latticevector normal to the planes
Q=ha1*+ka2*+la3*
Reciprocal lattice: h, k, l integersa2 a3
a2 a3a1. ( )
X
X
dhkl
Bragg law:2dhklsin(θB)=nλ
θB θB
I(Q) ∝ < Σ fj(Q) ei Q r >j2
atoms j
dhkl
Bragg law:2dhklsin(θB)=nλ
θB θB
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ABAB stacking of graphene sheets
a≈2.46Åc≈2 x 3.35Å
A
B
A
l
0
2
4
6
8
10
0 5 10 Q (Å-1)
00 10 11 20 12 30
II.2.a. Graphite
19
0 2 4 6 8 10 12 14 16
Q(Å-1)
Powder neutron diffraction patternN
orm
aliz
ed in
tens
ity (b
arns
)
A. Burian, J.C. Dore, H.E. Fischer and J. Sloan, Phys. Rev. B 59, 1665 (1999)
d002
d100
d12
1 2 3
d13
21
Direct space Reciprocal space
Stacking of ordered 1D chains with random ‘in-chain’ tranlations
Bragg peaks (h=0)+ diffuse lines
(Scattering theory again)
22
3.45 Å
Random stacking of graphene layers
0
2
4
6
8
10
0 5 10 Q (Å-1)
00 10 11 20 12 30
● Diffraction peaks (00l)● Diffuse lines (hk)
● Symmetric (00l) peaks● Sawtooth shaped (hk) reflectionsPowder
average
0 2 4 6 8 10 12 14 16Q(Å-1)
(10)
(002
)
0 2 4 6 8 10 12 14 16Q(Å-1)
Turbostratic carbon
l
23
II.3. Multi-walled carbon nanotubes (MWNT)
c
Russian dolls made of rolled up graphene sheets
c distance
AB stacking
Offset changes with Φ
Analogies with turbostratic carbon
Normal incidence diffraction patternof a multishell tube containing several isochiral clusters
from S. Amelinckx, A. Lucas and P. Lambin,Rep. Prog. Phys. 62, 1471 (1999)
(10)(002) (004)
(104)
Strong peaks: (00l), (hk)Weak (hkl) peaks if interplane corrrelations
Curvature fl diffuse streaks from (hk)
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● Diffraction peaks (00l)● Diffuse planes (hk) withasymmetric decreasing intensity
Powderaverage
● Symmetric (00l) peaks● Sawtooth shaped (hk) reflections
Neutron diffraction on MWNTs produced by arc discharge
c≈ 3.41Å for MWNTs
to be compared to3.35Å for graphite
A. Burian, J.C. Dore, H.E. Fischer and J. Sloan, Phys. Rev. B 59, 1665 (1999)
(10) and (11) peaks fl a≈2.46Å
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● Finite coherent domains (size)
● Distribution in parameters (strains)
D=Na
Q)Qsin()NQasin(ee Q)1N(i
N
1
Qna
aa
n
i
πππ +−
=
=∑
0 a* 2a* 3a* 4a* 5a*
2
)Qsin()QDsin()( ⎟⎟
⎠
⎞⎜⎜⎝
⎛∝
aQI
ππ
ΔQ∝1/D
fl peak broadening ∝1/size, independent of peak position
0 1 2 h (for Q=h<a*>)
ΔQ∝h
fl peak broadening ∝ peak position
(Still a little bit of theory of scattering…)
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D. Reznik, C.H. Olk, D.A. Neumann and J.R.D. Copley,Phys. Rev. B 52, 116 (1995)
X-ray diffraction on MWNTs produced by arc discharge
C.-H. Kiang, M. Endo, P.M. Ajayan, G. Dresselhaus
and M.S. Dresselhaus,Phys. Rev. Lett. 81, 1869 (1998)
HRTEM
Calculated distribution of
interlayer spacings
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Additional (hkl) peaks?
Scroll structures??Isochiral tubes??
Chapter III by P. Lambin, A. Loiseau, M. Monthioux and J. Thibault,
in‘Understanding Carbon Nanotubes : from science to applications’, A. Loiseau, P. Launois, P. Petit, S. Roche and J.-P. Salvetat Eds.,
Lecture Notes in Physics, Springer,vol. 677 (2006)
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Powder diffraction on MWNTs
● (hk) reflections: in-plane interactomic distances
● (00l) reflections:
- Mean distance c between walls
- Distribution
● Additional reflections?
Summary of part II.3
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II.4. Single-walled carbon nanotubes (SWNT)
Periodicity T along the tube axisfl scattered intensity is located in diffraction planes with
For detailed theory of kinematical diffraction on nanotubes, see e.g. S. Amelinckx, A. Lucas and P. Lambin, Rep. Prog. Phys. 62, 1471 (1999)
Chapter I by P. Delhaès, J.-P. Issi, S. Bonnamy and P. Launois,
in‘Understanding Carbon Nanotubes : from science to applications’, A. Loiseau, P. Launois, P. Petit, S. Roche and J.-P. Salvetat Eds.,
Lecture Notes in Physics, Springer,vol. 677 (2006)
30
0
Powder X-ray scattering calculations, P. Launois
S. Amelinckx, A. Lucas and P. Lambin, Rep. Prog. Phys. 62, 1471 (1999)
(10,10) SWNT
ΦT=13.56 ÅT=2.46 Å
http://www.photon.t.u-tokyo.ac.jp/~maruyama
4π
T
31
High Q values: atomic structure of NTBelow Q~2Å-1: NT can be considered as an homogeneous cylinder
ΦT
32
A. Thess , R. Lee, P. Nikolaev, H. J. Dai, P. Petit, J. Robert, C. H. Lee, S. G. Kim, G. Rinzler, D. T. Colbert, G. E. Scuseria, D. Tománek, J. E. Fischer, and R. E. Smalley ,
Science 273, 483 (1996)
Bundles of SWNTs organized on a 2D hexagonal lattice
x
y
ab
3.2Å
(1,0
)
(1,1
)
(2,1
)
(2,0
)
Finite bundle size:finite peak width
+ form factor modulations
fi peak shifts
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(1,1)(2,0) (2,1) (2,2), (3,1)
0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8
Experiment (X-rays, powder)calculation
Inte
nsity
Q(Å-1)
(1,0)
<ΦT> = 7.1 Å
FWHM = 1 Å
Bundle size ≈ 40Å
0,0
0,5
1,0
rayon des nanotubes (angstrom)12 Å 14 Å 16Å
FWHM
0
p(ΦT)
M. Chorro’s poster
( )( ) TT d )p( ΦQRJ2
QJσRf .2ΦQ1~I(Q)
ji,ij0
2T
0cTc ∑∫ ⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎠⎞
⎜⎝⎛ Φπ i
j
S. Rols, R. Almairac, L. Henrard, E. Anglaret and J.-L. Sauvajol, Eur. Phys. J. B 10, 283 (1999)
Careful fits of experimental data fl average NT diameter, distribution in diameter, average bundle size…
34
Powder diffraction on bundles of SWNTs
• average NT diameter
• distribution of diameters between bundles
• average bundle size…
But: poor sensitivity to the presence of small quantities of individual SWNTs
Summary of part II.4
35
II.5. Oriented nanotubes
H.W. Zhu, C.L. Xu, D.H. Wu, B.Q. Wei, R. Vatjai and P.M. Ajayan,
Science 296, 884 (2002)
D.A. Walters, M.J. Casavant, X.C. Qin, C.B. Huffman, P.J. Boul, L.M. Ericson, E.H. Haroz, M.J. O’Connell,
K. Smith, D.T. Colbert and R.E. Smalley, Chem. Phys. Lett. 338, 14 (2001)
C. Singh, M.S.P. Shaffer and A.H. Windle,
Carbon 41, 359 (2003)
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Textured materials, with preferred orientation
Single crystal
Powder
Gaussian fit
W. Zhou, J.E. Fischer, P.A. Heiney, H. Fan, V.A. Davis, M. Pasquali and R.E. Smalley,
Phys. Rev. B 72, 045440 (2005)
SWNT fiber fiber axis
NT
τ (deg)
τ
Gaussian fit
MWNT carpet
V. Pichot, P. Launois, M. Pinault, M. Mayne-L’Hermite and C. Reynaud,
Appl. Phys. Lett. 85, 473 (2005)
τ
37
I(τ) in reciprocal space Distribution of orientations (direct space)May not be obvious!
Rubber
Draw ratio 300%
From P.A. Albouy, LPS, Orsay France
Cis-polyisopropene
Stearic acid
G.R. Michell Polymer 25, 1562 (1984)
‘I(τ) may be considered to be the consequence ofsmearing or convoluting the scattering which wouldbe associated with a single orienting structure Iu(τ),
with the orientation function D(τ)’
The observed anisotropy in the scatteringmay be much smaller than
the anisotropy in the molecular orientation
τ
38
1/ Cylindrical symmetry
Distribution of orientations p(θ)
2/ l=0 diffraction patterns from SWNTs or (00l) peaks of MWNTs
INT ∝ δ(Qz’)
z’ ≡ NT long axis θ
ϕx
y
z
V. Pichot, S. Badaire, P.-A. Albouy, C. Zakri, P. Poulin
and P. Launois,Submitted
CASE STUDIED HERE
zz
39
1/ Orientation distribution function p Direct space
2/ Calculation of the integral Reciprocal space
40
W. Zhou, J.E. Fischer, P.A. Heiney, H. Fan, V.A. Davis, M. Pasquali and R.E. Smalley,
Phys. Rev. B 72, 045440 (2005)Gaussian fit
NT
τ (deg)
Gaussian fit
For p(θ)=Gaussian function, HWHM ≡ wd smaller than ~30° fi I(τ)=Gaussian function, HWHM ≡ wr > wd
θB = 5,9° (Q~ 0,7Å-1 at λ=1.542Å)
wd =15° Wr=15.25°
V. Pichot, S. Badaire, P.-A. Albouy, C.Zakri, P. Poulin and P. Launois, submitted
41
5.1
27664,01
1~)(
⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢
⎣
⎡
⎟⎟⎠
⎞⎜⎜⎝
⎛+
dw
pθ
θ
Wd=15°
( ) ( )2
2
21
1~
rw
Iπτ
τ−
+
Wr=14.9°
MWNT carpet
V. Pichot, P. Launois, M. Pinault, M. Mayne-L’Hermite and C. Reynaud,
Appl. Phys. Lett. 85, 473 (2005)
M. Mayne-L'Hermite, X. Armand, D. Porterat
and C. Reynaud,Proceeding of the CVD-XVI
and EUROCVD-14, 2003-2008, 549 (2003)
Inte
nsity
Lorentzian functions
τ
42
In many NT composites:
two-phase model, oriented and non-oriented fractions
p(θ) = (p1(θ)+f p2)/(1+f), p2=1/(4π)
43
Preferred orientations
QUANTITATIVE determination of the orientation distribution
… after detailed analysis:
width or shape of the angular distribution of intensities (reciprocal space)≠
width and shape of the distribution of orientations (direct space)
NB: for Gaussian functions of relatively small width, wd=wr.cos(θB)≈wr
Summary of part II.5
44
II.6. Composites: the other components
PVA = [ -CH2CHOH- ]nSWNT/PVA fibers
V. Pichot, S. Badaire, P.-A. Albouy, C. Zakri, P. Poulin
and P. Launois,submitted
distance between PVA chains ~ 4.5Å
AmorphousPVA
NTs
Hot drawing: PVA partial crystallisation
From V. Pichot PhD thesis, Université Paris XI, France (2005)
P. Miaudet, S. Badaire, M. Maugey, A. Derré, V. Pichot,P. Launois, P. Poulin and C. Zakri,
Nano Letters 5, 2212 (2005)
PVA chains alignment is templated by that of NTs
45
SWNT/Polyethylene (PE) composites
1/ Polyethylene [CH2=CH2]n Shish-Kebab structure in melt-spun fibers
ShishKebab
46
Spinneret
Extensional melt flow
Fibe
r axi
s
c
c
ba
Shish-Kebab structure in melt-spun fibers
Polymer Crystallization Schultz, Oxford University Press 2001
Shish
Kebab
47
Orientation in Melt-Spun PE FibersShish-Kebab structure in melt-spun fibers
Low shish density: kebabs twist
High shish density: kebabs grow straight
WAXS pattern
a
c b
a
c
b
Fibe
r ax
is
Slide from R. Haggenmueller, univ. of Pensylvania, USA
48
2/ SWNT/PE composite
R. Haggenmueller, J.E. Fisher and K.I. Wiley,Macromolecules 39, 2964 (2006)
SWNT bundles templatePE crystallization such that
lamellae grow perpendicular from the SWNT surface
with the PE chains (c-axis) parallel to the SWNT axis
49
On the exemples of SWNT / PVA or SWNT / PE
X-ray diffraction fi insight in SWNT and polymer interactions
50
bH= -0.374. 10-12 cmbD= +0.667. 10-12 cm
D2O H2O
Neutrons: isotopic contrast
ShellCore
Slide from L. Noirez, LLB, Saclay, France
51
Neutrons vs X-rays : contrast
N. Bendiab, R. Almairac, S. Rols, R. Aznar, J.-L. Sauvajol and I. Mirebeau,Phys. Rev. B 69, 195415 (2004)
15% 3%
Iodine localization in SWNT bundles
Slight expension of the tube-tube distance (~3%)
15% between NTs85% of iodine molecules inside NTs
52
Diffraction
• Structure and orientation of other components of the composite (e.g. polymers, catalysts of NT growth)
• Information about organization at NT-polymer interface…
Summary of part II.6 (other components)
53
Part II summary
X-rays: ~mm3
Neutrons: ~cm3
• Statistical characterization of the sample
• Contrast effects structure refinements
• MWNTs: mean distance c between walls, distribution of distances c, orientation
• SWNTs: mean diameter, distribution of diameters between bundles,inter-tube distance, bundle size, orientation
• Other components (catalyst, polymers,etc): structure (amorphous or crystalline polymers),orientationfl interface
Simulations/comparison with experiments
54
I. Rapid overview of the use of TEM, SEM, optical imaging or thermal analysis
II. X-ray or neutron diffraction
III. Raman spectroscopy
IV. Conclusion
Lecture’s scheme
1. Introduction 2. NT structure 3. Functionalization4. NT orientation
• Many thanks to Eric Anglaret (LCVN, Montpellier, France) for some of the slides and for discussions
• Nedjma Bendiab (IMPMC, Paris) is also acknowledged for discussions
55
ν1
III.1. A rapid introduction For a complete one: see Christian Thomsen lecture
• Incident radiation of frequency ν1
- Most of it is transmitted without change- Some scattering occurs
-at the same frequency ν1:Rayleigh scattering
- at a different frequency νM: Brillouin and Raman scattering
|νM-ν1| < 1 cm-1
Incident radiation = visible light fl wave-vector transfer smaller than ~10-3 Å-1
fl center of the Brillouin zone
Main origin of scattered radiation: oscillating electric dipole induced by the electromagnetic field
• Resonant Raman scattering
Raman intensity goes through a maximum for spectra excited with an energy corresponding to an optical absorption threshold of the material.
~1 μm3
Statisticalinformation
|νM-ν1| > 1 cm-1
56
‘Kataura plot’
0,5 1,0 1,5 2,0
0,5
1,0
1,5
2,0
2,5
3,0
Tran
sitio
n E
nerg
y (e
V)
Diameter (nm)
Métallics SC, (n-m) mod3=-1, (2n+m) mod3=1, type I SC, (n-m) mod3=1, (2n+m) mod3=-1, type II
Electronic and optical properties of SWNTs
A. Jorio, C. Fantini, M. A. Pimenta, R. B. Capaz, Ge. G. Samsonidze,
G. Dresselhaus, and M. S. DresselhausPhys. Rev. B 71, 075401 (2005)
DOS of a (10,10) metallic NT
The allowed optical absorption spectrum is strongly dependent on the NT structurefl Raman spectra change with laser energiesfl Modes of different NTs are probed for different laser energies
H. Kataura, Y. Kumazawa, Y. Maniwa,I. Umezu, S. Suzuki, Y. Ohisuka and Y. Achiba
Synthetic Metals 103, 2555 (1999)
57
III.2. NT structure (diameter)
Radial breathing mode(RBM)
200 cm-1
A1g
200 400 600 800 1000 1200 1400 1600
TM
RBM 1.92 eV
ν (cm-1)
Ram
an in
tens
ity (a
.u.)
Electric arc SWNT sample
200 400 600 800 1000 1200 1400 1600
RBM
TM2.41 eV
Ram
an in
tens
ity (a
.u.)
ν (cm-1)
Tangential modes (TM)
1578 cm-1 1583 cm-1 1585 cm-1
A1g E1gE2g
58
Chapter V by J.-L. Sauvajol, E. Anglaret, S. Rols and O. Stéphan,
in‘Understanding Carbon Nanotubes : from science to applications’, A. Loiseau, P. Launois, P. Petit, S. Roche and J.-P. Salvetat Eds.,
Lecture Notes in Physics, Springer,vol. 677 (2006)
νRΒΜ(cm-1)=224/d(nm) for isolated SWNTs νRBM(cm-1)=224/d(nm)+14 for bundles
59
SWNT diameters in macroscopic samplesfrom RBM frequencies using Raman scattering?
Raman scattering / X-ray or neutron scattering:
(+) probes all tubes: isolated and in bundles, while diffraction methods are more sensitive to tubes organized in bundles
(-) only a semi-quantitative picture of the diameter distribution, even by scanning the Raman spectra over a broad range of laser excitation energies
Resonance:
mode intensity does not depend only on the number of nanotubes
with a given characteristic (diameter…)but also on the laser excitation energy
S. Rols, A. Righi, L. Alvarez, E. Anglaret, T. Almairac, C. Journet, P. Bernier, J.L. Sauvajol, A.M. Benito,
W.K. Maser, E. Muňoz, M.T. Martinez, G.F. de la Fuente, A. Girard and J.C. Ameline,
Eur. Phys. J. B 18, 201 (2000)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40
50
100
150
200
250
300
350
νRBM(cm-1) = 224 / d + 14
νRBM(cm-1) = 224 / d
Isolated tubes, calculations Bundles, calculations X-ray scattering results
RB
M fr
eque
ncy
(cm
-1)
1/d (nm-1)
60
MWNTs
D band‘Defects’
G band‘tangential
modes’
Graphite
The D bandshould be non active
in Raman.
Is due to a double resonantprocess which involves scattering of an electron on a structural ‘defect’.
N. Bendiab, M. Mayne-L’Hermite et al,in preparation
CVD MWNTs carpets
Small values of Γ and ID/ID*:high ‘degree of crystallinity’
1200 1300 1400 1500 1600 1700
Γ=38 cm-1 1618 cm-11354 cm-1
1579 cm-1
ν (cm-1)
Inte
nsity
(a. u
.)
D-band
G-band
1st order 2nd order
D* band
61
Electric arc MWNTs
MWNTs with small internal diametersfi RBM modes are observed
J.M. Benoit, J.P. Buisson, O. Chauvet, C. Godon and S. Lefrant,
Phys. Rev. B 66, 073417 (2002)
62
Part III.2 summary
NT structure probed with Raman scattering
Semi-quantitative information on diametersand on ‘crystallinity’ for MWNTs
Sensitivity to isolated tubes
63
III.3. Functionalization
J.L. Bahr, J. Yang, D.V. Kosynkin, M.J. Bronikowski, R.E. Smalley and J.M. Tour, J. Am. Chem. Soc. 125, 8566 (2003)
The relative intensity of the D mode is greater for functionalized nanotubes:
may be due to the introduction of covalent bonds moieties to the nanotube framework, wherein significant amount of the sp2 carbons have been converted to sp3 by hybridization
64
III.4. Orientation
z
x
Laser
Ei=V Ed=V
Laser
ψ
x
zEi=V
Ed=H
ψ
Polarized Raman studies
VV configuration VH configuration
Variations of intensities of the different modes as a function of the angle ψ(sample/nanotubes orientation) in VV or VH configurationsfl NT orientations
650.8
1.0
H,4
5°
0.2
0.4
0.6
0.8
1.0
RBM, 2.41 eV TM, 2.41 eV
RBM, 1.92 eV TM, 1.92 eV
I VV/I V
V,0
° -90 -60 -30 0 30 60 90
F(β)
β (°)
Fibers of SWNTs
VV configurationλ=647.1nm
H.H. Gommans, J.W. Alldredge,
H. Tashiro, J. Park, J. Magnuson
and A.G. Rinzler,J. Appl. Phys. 88,
2509 (2000)
E. Anglaret, A. Righi, J.L. Sauvajol,
P. Bernier, B. Vigolo and P. Poulin,
Phys. Rev. B 65,165426 (2000)
ψ(°)0 15 30 45 60 75 90
Carpets of MWNTs
A.M. Rao, A. Jorio, M.A. Pimenta, M.S.S. Dantas,R. Saito, G. Dresselhaus and M.S. Dresselhaus,
Phys. Rev. Lett. 84, 1820 (2000)
ψ ψ
66
MWNTsz
xLaser
Ei=V Ed=V
ψ
ψ ψ
In agreement withnonresonant bond-polarization
calculations
Intensity of the tangential A1g modeminimum at ψ=54.7°
R. Saito, T. Takeya, T. Kimura, G. Dresselhaus and M.S. Dresselhaus,
Phys. Rev. B 57, 4145 (1998)
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
1 4 0
1 6 0
1 0 3 0 5 0 7 0 9 0
V V
Inte
nsit
é θ ( ° )
R o ta tio n a u to u r d e l 'a xe Y
T M ,A1 g
Z Z X Xψ (°)
A. Rahmani, J.L. Sauvajol, S. Rols and C. Benoit,Phys. Rev. B 66, 125404 (2002)
67
SWNTs
• Resonant scattering and anisotropic absorption• ‘Antenna effect’: Raman tensor is anisotropic,
hypothesis: only one nonzero component εzz
Ei=V [0, sin(ψ), cos(ψ)]
Ed=V [0, sin(ψ), cos(ψ)]Ed =H [0, cos(ψ), sin(ψ)]
For one NT, in the referential XfYfZf of the fiber:INT(ψ,θ,ϕ)=∑ EdA EdA’ εAB εA’B’ EiB EiB’ with
Yf
ZZf
ψ
Y
Ed=V
Ed=H
Ei=V
Xf
Zf
Yf
zθ
ϕ
and εAB =∑ RΑz RΒz εzz εzz RΑ’z RΒ’z
where [R] is the rotation matrix that goes from the NT frame to the fiber frame
From E. Anglaret, A. Righi, J.L. Sauvajol, P. Bernier, B. Vigolo and P. Poulin,Phys. Rev. B 65, 165426 (2002)
INT =∑ EdAEdA’ RAz RB ’z RA ’z RB ’z’ εzz εzz EiB EiB’
For a fiber, average over all orientations
Ifiber(ψ)= ∫ ∫ INT(ψ,θ,ϕ) p(θ) sinθ dθ dϕ
69
Polarized Raman & X-ray scattering fl p(θ) = (p1(θ)+f p2)/(1+f), p2=1/(4π)
• Comparison between Raman and X-ray results obtained on SWNT/PVA fibersfl disagreement!
Why?Is the hypothesis of only one nonzero component εzz in the Raman tensor correct?Or …???
E. Anglaret, A. Righi, J.L. Sauvajol, P. Bernier, B. Vigolo and P. Poulin, Phys. Rev. B 65, 165426 (2002) P. Launois, A. Marucci, B. Vigolo, P. Bernier, A. Derré and P. Poulin, J. Nanosci. Nanotechnology 1, 125 (2001)
Still open questions…
• Complementary use of X-ray scattering to determine FWHM and f
W. Zhou, J. Vavro, C. Guthy, K.I. Winey, J.E. Fischer, L.M. Ericson, S. Ramesh, R. Saini, V.A. Davis, C. Kitrell, M. Pasquali, R.H. Hauge and R.E. Smalley, J. Appl. Phys. 95, 649 (2004)
70
I. Rapid overview of the use of TEM, SEM, optical imaging or thermal analysis
II. X-ray and neutron diffraction
III. Raman spectroscopy
IV. Conclusion
Lecture’s scheme
71
Homogeneity
NT rate, composition
NT structural parameters
Matrix characteristics
Alignment
Adhesion between NTs and matrix
IV. Conclusion
Optical imaging
Scanning Electron Microscopy
Raman scattering
X-ray and neutron scattering
Thermal analysis
Transmission Electron Microscopy
72
Dramatic change in length-scales involved, from a macroscopic material to its nanoscopic components:
complementary analyses at different scales have to be performed
Spatial resolution
Optical microscopy ~μm(polarization)SEM ≥10 nm
TEM ≤ nm
73
Neutrons
X-rays
Raman
Volumeprobed
cm3
μm3
mm3
to μm3
(micro-diffraction)
Statistical characterization
• SWNTs fl NTs in bundles: average NT diameter, distribution of diameters, average bundle sizeBut not sensitive to isolated SWNTs
• SWNTs fl probes all tubes: isolated and in bundles
But gives only a semi-quantitative picture of the diameter distribution
• Structure and orientation of other components of the composite (e.g. polymers)• Organization at NT-polymer interface
Neutrons orX-rays
+neutrons:Contrast
Supplementary information
• Functionalization
• Orientation of SWNTs and MWNTs
• Orientation of SWNTs and MWNTs
Raman and X-rays
for orientationdetermination:
complementarity or
discrepancies?
• MWNTs fl mean distance c between walls and distribution in distances; coherence in stacking