SUPPORTING INFORMATION:
In-situ Polymerization Functionalization of Single-walled Carbon
Nanotubes with Polystyrene
Matthew J. Kayatin, Virginia A. Davis
Department of Chemical Engineering, Auburn University
Sample # Li (mg) 4-Bromostyrene dose
Details
1
60
105 μL
3 additions, quenched
2
120
420 μL
1 addition
3
120
105 μL
Quenched at start of 4th addition
Table S1. Experimental conditions for PbS SWNT products.
0.5
Sample 1
Sample 2
Sample 3
Absorbance (a.u.)
0.4
0.3
0.2
0.1
0.0
3850
3450
3050
2650
2250
1850
1450
1050
650
Wavenumber (cm-1)
Figure S1. ATR-FTIR spectra for PbS SWNT products showing similarity in surface
chemistry.
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Kayatin and Davis
In-situ Polymerization Functionalization of Single-walled Carbon Nanotubes with Polystyrene
1.0
Single Addition
Three Additions
SWNT
Derivative Wt. (%/°C)
0.8
0.6
0.4
0.2
0.0
100
200
300
400
500
Temperature (°C)
600
700
Figure S2. TGA derivative mass loss curves for SWNT and PS SWNT with varied number
of monomer addition steps showing changes in weight percent with temperature. Oven
atmosphere was argon.
1.0
SWNT
60 mg Li
90 mg Li
120 mg Li
Derivative Wt. (%/°C)
0.8
0.6
0.4
0.2
0.0
100
200
300
400
500
Temperature (°C)
600
700
Figure S3. TGA derivative mass loss curves for SWNT and PS SWNT functionalized by
three monomer additions using varied Li to C ratio showing changes in weight percent
with temperature. Oven atmosphere was argon.
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Kayatin and Davis
In-situ Polymerization Functionalization of Single-walled Carbon Nanotubes with Polystyrene
0.012
2932
Absorbance (a.u.)
0.010
0.008
0.006
2965
2865
0.004
0.002
0.000
3400
3300
3200
3100
3000
2900
Wavenumber (cm-1)
2800
2700
2600
Figure S4. Gas-phase TGA-FTIR spectrum of C12 SWNT at 250 °C. Peaks were typical for
expected C-H stretching vibrations from aliphatic hydrocarbons. The asymmetric CH3
vibration was found at 2965 cm-1. The asymmetric -CH2- vibration was found at 2932
cm-1. Symmetric aliphatic C-H vibrations were found at 2865 cm-1.
Pristine
Dodecylated
1.0E+05
Intensity (a.u.)
7.5E+04
5.0E+04
2.5E+04
0.0E+00
0
400
800
1200
1600
2000
Raman Shift (cm-1)
2400
2800
3200
Figure S5. Resonant Raman spectra for pristine SWNT and C12 SWNT under 514 nm
excitation laser.
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Kayatin and Davis
In-situ Polymerization Functionalization of Single-walled Carbon Nanotubes with Polystyrene
Weight Percent (%)
100
80
60
PMMA SWNT
SWNT
40
100
200
300
400
500
Temperature (°C)
600
700
Figure S6. TGA mass loss curves for SWNT and PMMA SWNT produced using the in-situ
polymerization functionalization scheme showing changes in weight percent with
temperature. Oven atmosphere was argon.
0.0030
Absorbance (a.u.)
0.0025
0.0020
0.0015
0.0010
0.0005
0.0000
3100
2900
2700
2500 2300 2100
Wavenumber (cm-1)
1900
1700
1500
Figure S7. Gas-phase TGA-FTIR spectrum of PMMA SWNT at 370 °C. Carbonyl vibrations
from ester groups were found at 1740 cm-1. Due to the low boiling point of methyl
methacrylate (~101°C), the observed carbonyl vibrations were attributed to polymer
degradation. Various carbon oxides were detected at 2340 cm-1. Aliphatic C-H
vibrations were found from 2800 - 3000 cm-1.
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Kayatin and Davis
In-situ Polymerization Functionalization of Single-walled Carbon Nanotubes with Polystyrene
Additional Experimental Details:
Methods: All reaction flasks were cleaned with soap and kept overnight in a KOH base
bath. Glassware was rinsed with deionized water, acetone, and checked for any visible
residues.
Bath sonication was carried out using a One-Pint ultrasonic cleaner (55 kHz) purchased
from Cole Parmer and filled with tap water. The output power was reported to be 20 W
but the effective power is decreased depending on the nature of the container, its
orientation, and solvent used.
The f SWNT was carefully scraped from the filter paper to avoid grease contamination
and placed in a weigh boat to air dry before being moved to a glass vial. The product
was vacuum dried overnight. Dry samples were easily broken up with a spatula before
use.
Characterization: Polyvinylpyrrolidone (Ave. MW 58,000) was purchased from Acros
Organics (K29-32) and desiccated. A solution of 10 mg PVP per mL of water was used. A
SWNT concentration of 0.31 mg/mL was chosen. Five mg of pristine SWNT was added
to a vial with 15 mL of PVP stock solution and this was bath sonicated for 20 min to start
the dispersion and coating process. Bath sonication was needed to prevent undesirable
foaming during tip sonication. The sample was placed in an ice bath and allowed to cool
for 20 min. Cooling was required to prevent selective PVP desorption. 1 The cold sample
was tip sonicated at 60 % amplitude for 30 min with a 5 s on and 3 s off pulse within an
ice bath. A Vibra-Cell VC 750 from Sonics was used for tip (1/2”) sonication. The sample
was allowed to settle overnight to precipitate aggregated and high density material.
The sample was then decanted and the residue discarded. The sample was spun down
at 17,000 x g for 3 hours based on the isolation of SWNT in double-stranded DNA.2
Samples were then decanted and diluted as necessary for qualitative UV-vis spectra.
Note that optical properties are not affected by excess PVP.3 A Varian Cary 3E UV-Vis
spectrophotometer was used for absorbance measurements. Samples were placed in a
Starna semi-micro quartz cell with 10 mm path length and compared to the background
of solvent.
Both diamond and germanium single-bounce ATR crystals were used. For solid samples
such as powders and films, the high pressure clamp was used and was equipped with a
10,000 psi clutch. The diamond crystal had a reported depth of penetration of 2.03 μm
at 1000 cm-1 and a refractive index of 2.4. The germanium crystal had a high refractive
index of 4.0 and a reported shallow depth of penetration of 0.67 μm at 1000 cm-1, ideal
for highly absorbing samples like SWNT.
TGA samples were analyzed for lithium content and purity by switching oven
atmosphere from argon to air at high temperature (e.g. argon post-test). TGA pans
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Kayatin and Davis
In-situ Polymerization Functionalization of Single-walled Carbon Nanotubes with Polystyrene
were cleaned of catalyst residue by bath sonication in a 10 vol. % solution of nitric acid
(70 %) in water. After rinsing the pan in clean organic solvent, the pan was flame
cleaned using a butane torch before use.
References
1 Feng, J.; Alam, S. M.; Yan, L. Y.; Li, C. M.; Judeh, Z.; Chen, Y.; Li, L. J.; Lim, K. H.; ChanPark, M. B. The Journal of Physical Chemistry C 2011.
2 Ao, G.; Nepal, D.; Aono, M.; Davis, V. A. ACS Nano 2011.
3 Bonnet, P.; Buisson, J.; Martyr, N. N.; Bizot, H.; Buelon, A.; Chauvet, O. Physical
Chemistry Chemical Physics 2009, 11, 8626-8631.
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