Polyaniline-Carbon Nanotube Composites: From Wrapping and ...€¦ · Carboquímica 2nd NANOSPAIN...
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Polyaniline-Carbon Nanotube Composites: From Wrapping and Self-Alignment to Solubility and Enhancement Effects MEC Wolfgang Maser Instituto de Carboquímica 2 nd NANOSPAIN Workshop Barcelona, March 14-17, 2005 Raquel Sainz, Ana M. Benito, M.T. Martínez, Wolfgang Maser Instituto de Carboquímica (CSIC) Zaragoza, Spain
Transcript of Polyaniline-Carbon Nanotube Composites: From Wrapping and ...€¦ · Carboquímica 2nd NANOSPAIN...
Polyaniline-Carbon Nanotube Composites:
From Wrapping and Self-Alignment
to Solubility and Enhancement Effects
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
Raquel Sainz, Ana M. Benito, M.T. Martínez, Wolfgang Maser
Instituto de Carboquímica (CSIC)Zaragoza, Spain
SOLUBLE PROCESABLE,TRANSFORMABLE
Aligned
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
Polyaniline / Multi-wall Carbon Nanotube Composite
400 nm
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
IN-SITU POLYMERIZATION
Emeraldine Salt/MWNT
+
NH2polymerization
30 wt%MWNTs
NH4OH
Emeraldine Base/MWNT
Soluble in NMPN
O
CH3
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
UV-VisEB and EBMWNT in NMP
EB
ππππ-ππππ*B Exciton
ππππ-ππππ*Q
•“FREE EB”
• QUNIOIDENHANCED
RESPONSE OFEB IN THE
COMPOSITE;
• MWNT related
EBMWNT
0 200 400 600 800 1000 1200 1400
-1.5
-1.4
-1.3
-1.2
-1.1
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
d(w
t%)/
dT
Temperature(ºC)
(a) MWNTs(b)EB(c) EBMWNTs
745ºC
686ºC470ºC
0 200 400 600 800 1000 1200 1400
-1.5
-1.4
-1.3
-1.2
-1.1
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
d(w
t%)/
dT
Temperature(ºC)
(a) MWNTs(b)EB(c) EBMWNTs
745ºC
686ºC470ºC
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
THERMOGRAVIMETRIC ANALISIS
• Two-phases (EB + new Q-rich EB)
• Thermal stability EBMWNT > EB
EBMWNT
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
QUINOID RELATED PEAKS INCREASEDCOMPARED TO BENZENOID IN EBMWNT
2000 1800 1600 1400 1200 1000 800 600 400
EB
EBMWNTs
abso
rban
ce (
a.u.
)
wavenumber (cm-1)
C-C str
Q B Q
C-H ben
Q
ring-def
QB
C=N str
Q B
N=Q=N
Q
C=O
1< 1N=Q=N1122
< 1< 1B related1165
1<< 1C-C (Q)1380
1< 1C=N (Q)1465
˜ 1˜ 1C-C (B)1494
1< 1C=C (Q)1585
Rel.Int.
EB-MWNT
Rel.Int.EB
Assignmentνννν (cm-1)
FTIR SPECTROSCOPY
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
• Only seen: “free EB-I” and MWNT• MWNTs do not affect EB unit cell• Quinoid-rich PANI phase???
X-RAY DIFFRACTION
EBMWNT
EB-I unit-cell:• c = 0.94 nm,
• b = 0.57 nm,
• a = 0.45 nm
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
CONDUCTIVITY
EBMWNTESMWNT
ES
X EB
σσσσ(EB) ≤ ≤ ≤ ≤10-10 S/cm σσσσ(EBMWNT) ≈≈≈≈ 0.1 S/cm ≈≈≈≈ σσσσ(ESMWNT) σσσσ(EBMWNT) < 1-10 S/cm = σσσσ(MWNT)
• Conduction through apercolated 3D network of
MWNTs
• EBMWNT conductivityis 9 orders of magnitude
higher than EB
• Existence of additionaltunnelling barriersbetween MWNTs
At RT:
200 nm
Phase200 nm 2D Topo
(Deriv)
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
Topography
200 nm
Phase
200 nm
Adhesion
200 nm
• “Free EB”• Bundles of aligned polyaniline covered MWNTs
ATOMIC FORCEMICROSCOPY
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
3D Topography
2 µµµµm x 2 µµµµm
400 nm
Topography
ATOMIC FORCEMICROSCOPY
• 3D NETWORK OF ALIGNEDPANI-COVERED MWNTs
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
• TWO PHASES: FREE EB AND MWNTs+EB
• QUINOID ENHANCED RESPONSE IN EB-MWNT
• CHANGE OF THE EB CONFORMATION• MORE PLANAR CONFORMATION
ALONG MWNTs
WHAT IS GOING ON?
In-situ polymerizationKey:
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
• new, more planar, conformation of PANI wrapping around MWNTs
• Stabilization by
- strong ππππ- ππππ interaction and simultaneously
- self-organization of randomly oriented planar-PANI-covered MWNTs into aligned bundles
Conformational Changes
• Solubility and Processability• Enhanced functionality (electrical and thermal properties) of PANI-MWNT composite
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
Summary
•Processable, highly conducting, thermally stable andluminiscent EB/MWNT composite
•Completely soluble EB/MWNT composite composed of apure EB matrix and of EB-coated MWNTs
•MWNT coating EB layer has a more planar conformationfavouring the interaction between EB and MWNTs
•EB-coated MWNTs form aligned bundles resulting in a3D network throughout the EB matrix
R. Sainz, Adv. Mater, 17, 281 (2005)R. Sainz, Nanotechnology, 16, 150 (2005)
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
B Corraze
O Chauvet
RESEARCHERS
AFM-Group@Carboquímica
Javier Sotres
Juan Galindo
Arturo Baró
Raquel Sainz
Ana Mª Benito
Wolfgang Maser
Mª Teresa Martínez
Carboquímica
MEC
Wolfgang MaserInstituto de
Carboquímica
2nd NANOSPAINWorkshop
Barcelona, March 14-17, 2005
THANKS
ACKNOWLEDGEMENT
A B DaltonR H Baughman
MEC: Proyecto NANOSIN (MAT2002-04540-C05-04)
Jonathan Coleman
Werner Blau
TCD Dublin
