LPD Silica Coating of Individual Single Walled Carbon ...

Electronic Supplementary Material for Journal of Materials Chemistry This journal is © The Royal Society of Chemistry 2005

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LPD Silica Coating of Individual Single Walled Carbon Nanotubes

Elizabeth A. Whitsitt,a Valerie C. Moore,a,b Richard E. Smalley,a,b,c and Andrew R. Barrona,c,d*

a Department of Chemistry, Rice University, Houston, Texas 77005, USA

b Carbon Nanotechnology Laboratory, Rice University, Houston, Texas 77005, USA

c Center for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA

d Department of Mechanical Engineering and Materials Science, Rice University, Houston,

Texas 77005, USA

Supplementary Materials


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30

35

40

45

50

55

60

65

60010001400180022002600300034003800Wavenumber (cm-1)

Trans. (%)

Si-O-Si

Si-FSi-O-Si

C-H

Fig. S1. ATR-IR of dried SiO2-SWNTs, prepared from DTAB-SWNT solution, with assigned

peaks.


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80

90

100

0 100 200 300 400 500 600 700 800 900 1000Temperature (°C)

TG

A (%

)

Fig. S2. TGA of SiO2-SWNTs in air.


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5

15

25

35

45

55

65

75

60010001400180022002600300034003800

Tra

nsm

ittan

ce (%

)

Si-O-Si

Si-O-Si

Wavenumber (cm-1) Fig. S3. ATR-IR of SiO2-SWNT solid after heating to 1000 °C.


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0

200

400

600

800

1000

1200

1400

100 600 1100 1600 2100 2600 3100

Inte

nsity

Wavenumber (cm-1)

Fig. S4. Raman (532 nm excitation) of SiO2-SWNT solid after heating to 1000 °C.


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0

290295 285 280

1000

2000

3000

4000

Binding Energy (eV)

Counts

5000(a)

Counts

400

300

200

100

298 294 290 286 282 278Binding energy (eV)

(b)

Fig. S5. Deconvoluted C1s XPS spectra for (a) raw SWNTs and (b) SiO2-SWNTs.


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Fig. S6. X-ray diffraction from SiO2-SWNTs showing the amorphous halo due to the silica

coating.


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0

100

200

300

400

500

600

700

800

900

0 0.5 1 1.5 2 2.5 3KeV

Si

Au

O

C

F

Fig. S7. Electron dispersive spectrum (EDS) of SiO2-SWNT fabric on Au.


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2500 2550 2600 2700 2750Wavenumber (cm-1)

2650 2800

2

3

4

7

Counts (103)

8

1

5

6

Fig. S8. Raman spectra (532 nm excitation) showing the G� mode of SWNT during the coating

reaction.


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Fig. S9. SEM of SiO2-SWNTs formed from DTAB-SWNT solution after 15 min reaction in

LPD solution.


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Fig. S10. SEM images of silica layer with SiO2-SWNTs formed from DTAB-SWNT solution

with an excess of silica, showing the coated SWNTs emerging from underneath and between

cracks in the silica matrix.


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Fig. S11. SEM of SiO2-SWNTs, prepared from DTAB-SWNT solution, with excess SiO2

colloids.


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Fig. S12. SEM images of SiO2-SWNTs (a) before and (b) after TGA to 1000 °C.


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Fig. S13. SEM image of etched ends of coated SWNTs.


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HF etch

Fig. S14. Schematic representation of spontaneous interconnects between exposed SWNTs.


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500 1000 1500 2500 3000Wavenumber (cm-1)

20000

2

4

6

8

Counts (105)

Fig. S15. Raman spectrum of SDS-SWNT solution (red) with subsequent addition of LPD

growth solution (gray). The inset image shows the relative intensities of the Raman G band

(blue) and the 8,3 SWNT fluorescence band (green) as a function of reaction time.


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500 1000 1500 2500 3000Wavenumber (cm-1)

20000

2

4

6

8

Counts (105)

Fig. S16. Raman spectrum of DTAB-SWNT solution at varying pH.


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1300 1400 1500 1700 1800Wavenumber (cm-1)

1600

2

4

6

8

Counts (103)

10

Fig. S17. Raman spectra (532 nm excitation) showing the D and G modes of SWNT during the

coating reaction.


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2

4

6

12

Counts (104)

0

8

10

1200 1300 1500Wavenumber (cm-1)

1400 1600

Fig. S18. Raman spectrum (785 nm excitation) of SWNT coating reaction showing the D and G

modes, (a) before and (b) after LPD silica coating.


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400 1400600 800 1000 1200wavelength (nm)

0.2

0.3

0.4

0.1

Absorbance

Fig. S19. Normalized UV/vis spectrum of 1% DTAB-SWNT solution (pink) versus SiO2-SWNT

solution (blue).


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Fig. S20. SEM of SiO2-SWNT �fabric,� formed from DTAB-SWNT solution, deposited onto an

aluminum SEM stub.


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Fig. S21. SEM images of SiO2-SWNT fabric on the edge of a cut PES filter.


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Table S1. XPS binding energies for raw and SiO2-SWNTs.

Sample raw SWNT SiO2-SWNT (eV) (eV)

C1s 284.36 284.52

285.35 285.25

287.10 288.43

290.50 290.34

O1s 530.47 532.42

534.67 536.48

Si2p n/a 105.30

107.13

F1s n/a 689.45

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