module 5 composites and macroscopic assemblies of … · module 5 composites and macroscopic...

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

3

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)

5

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

7

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

8

+ 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

9

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)

10

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)

11

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

12

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

13



1. Theory 2. Graphite and turbostratic carbon 3. Multi Walled Nanotube powders4. Single Walled Nanotube powders5. Oriented nanotubes6. Composites: the other components


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

15

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

16

Direct space Reciprocal space

Ordered lattice

integersintegers

17

Crystal

2π/λ

Reciprocal space origin

Ewald sphere

O

Single crystal

O2θ

Powder

I(Q) or I(2θ)

18

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

20

3.45 Å

Random stacking of graphene layers

Turbostratic carbon

II.2.b. Turbostratic carbon

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)

24

● 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

25

● 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…)

26

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

27

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)

28

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

29

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,



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

33

(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


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)

36

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


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


II. X-ray or neutron diffraction


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,



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

68

VV

VH

Good agreement betweenmeasurements and calculation

for a lorentzian distribution, FWHM=30°

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




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

module 5 composites and macroscopic assemblies of … · module 5 composites and macroscopic...

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