Supporting Information

Silsesquioxane−Polythiophene Hybrid copolymer as an

efficient modifier for single-walled carbon nanotubes

Shuxi Gao **, Xiaoyong Hu 1, Lei Zhang, Yuliang Mai, Hao Pang, Yongqiang Dai,

Fang Lu, Bin Liao *

Guangdong Provincial Key Laboratory of Industrial Surfactant, Guangdong Research Institute of

Petrochemical and Fine Chemical Engineering, Guangzhou 510000, Guangdong P. R. China

* Corresponding author.

** Corresponding author. E-mail: gaoshuxi @163.com 1Shuxi Gao and Xiaoyong Hu contributed equally to this work.

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Content1. Experimental................................................................................................3

1.1 Synthesis processes...................................................................................31.1.1 Synthesis of S-1-dodecyl-S’-(R, R’-dimethyl-R’’-acetic acid)trithiocarbonate (DTTC) and S-1-dodecyl-S’-(R, R’-dimethyl-R’’- (2-Thienyl) ethyl acetate)trithiocarbonate (DTTC-Th)................................................................31.1.2 Synthesis of functionalized T10 containing thiophene rings (T10(5-5)).................41.1.3 Synthesis of linear copolymer PDMA-b-PMA.............................................51.1.4 Synthesis of linear copolymer PDMA-b-PMA-Th........................................71.1.5 Synthesis of T10-(PDMA-b-PMA)-Th copolymer precursor (M5-5)...................81.1.6 Synthesis of the star-shaped conjugated copolymer T10-(PDMA-b-PMA)-PEDOT (P5-5) and the linear analogue PDMA-b-PMA-b-PEDOT......................................9

1.2 General Procedure for obtaining the pristine SWNTs, SWNTs dispersion, modified SWNTs and supernatant liquid........................................................................111.3 Synthesized of PEDOT homopolymer by interfacial polymerization.....................12

2.Additional Results........................................................................................13References....................................................................................................14

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1. Experimental

1.1 Synthesis processes

1.1.1 Synthesis of S-1-dodecyl-S’-(R, R’-dimethyl-R’’-acetic

acid)trithiocarbonate (DTTC) and S-1-dodecyl-S’-(R, R’-dimethyl-R’’- (2-

Thienyl) ethyl acetate)trithiocarbonate (DTTC-Th)

S-1-dodecyl-S’-(R, R’-dimethyl-R’’-acetic acid)trithiocarbonate (DTTC) was

prepared following the steps in Ref. 1 [1].

FTIR (KBr, νmax/cm-1): 1727 (C=O).1H NMR (CDCl3, δ/ppm): 0.85 (t, 3H), 1.20~1.40 (m, 18H), 1.59~1.69 (m, 2H),

1.69 (s, 6H), 3.24 (t, 2H).

Figure S1. 1H NMR of DTTC

2-Thiopheneethanol (0.9216g, 7.2mmol), DTTC (2.184g, 6mmol), N,N′-

Dicyclohexylcarbodiimide (DCC, 1.4832g, 7.2mmol), 4-Dimethylaminopyridine

(DMAP，0.0732g, 6mmol) were dissolved in dry tetrahydrofuran (THF, 5 mL) in

Schlenk tube. The tube was quickly subjected to three freeze-pump-thaw cycles and

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stirred during 24 hours at 25 oC. Next, the crude mixture was concentrated after

passing a filtration. Then, Purification of the crude mixture by column

chromatography (silicagel, ethyl acetate/petroleum ether=1:25) yielded the DTTC-Th

(1.8853g, 3.98mmol, 66%, C23H38O2S4, 474g/moL) as yellow oil. The final product

was dried at room temperature in a vacuum oven for 48h.

FTIR (KBr, νmax/cm-1): 818 and 891 (C-S in the thiophene ring), 1379 and 1495 (C-

S and C=C in the thiophene ring), 1058 (C=S), 1293 (C-S-C), 1707 (C=O).1H NMR(CDCl3, δ/ppm): 0.87 (t, 3H), 1.22~1.36 (m, 18H), 1.59~1.64 (m, 2H),

1.69 (s, 6H), 3.15(t, 2H), 3.24 (t, 2H), 4.31 (t, 2H), 6.85 (d, 1H), 6.91 (t, 1H), 7.14(d,

1H).

Figure S2. 1H NMR of DTTC-Th

1.1.2 Synthesis of functionalized T10 containing thiophene rings (T10(5-5))

DL-N-acetylhomocysteine thiolactone (ACTA, 1.908 g, 12 mmol) and 4-

dimethylaminopyridine (DMAP, 0.0732 g, 0.6 mmol) were dissolved in dry 1, 4-

dioxane (18 mL) in Schlenk tube, and the resulting solution was purged with nitrogen

for 30 min, with subsequent addition of 2-thiopheneethylamine (TPEA, 0.762 g, 6

mmol). After the addition, the tube was quickly subjected to three freeze-pump-thaw

cycles followed stirring for 8 hours at 40 °C.

Next, degassed T10/1, 4-dioxane solution (2.1492 g/5 mL, 0.24 mmol/mL) was

injected into the tube via a syringe and the reaction solution was stirred at 40 °C for

14 hours. After the solvent was pumped out, the obtained viscous liquid was washed

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with deionized water under vigorous stirring three times and dissolved in

dichloromethane (20 mL), the resulting solution was further purified from traces of

water by passing over 4A molecular sieve and concentrated.

Finally, T10(5-5) (1.2 g, 31%) was obtained as faint yellow viscous liquid after

purification by flash chromatography (4:1 petroleum ether/ethyl acetate), and dried at

room temperature in a vacuum oven for 48 h, verified by FTIR, 1H NMR, MALDI-

TOF.

FTIR (KBr, νmax/cm−1): 693 and 820 (C−S in the thiophene ring), 1120 (O−Si−O),

1200 (C−O−C), 1377 (C=C in the thiophene ring), 1439 (C−S−C), 1543(C−N),

1636(C=C), 1653 (O=C−NH), 1720 (C=O), 3072 (C−H in olefin), 3287 (N−H).1H NMR(CDCl3, δ/ppm): 0.57−0.89 (m, 20H), 1.15−1.25 (m, 10H), 1.49−1.79 (m,

20H), 1.90 (s, 15H), 1.96(d, 15H), 2.05 (s, 15H), 2.31−2.81 (m, 20H), 2.85−3.10 (m,

15H), 3.18−3.67 (m, 20H), 4.00−4.10 (m, 10H), 4.48−4.58 (m, 5H), 5.46−6.20 (d,

10H), 6.82(m, 5H), 6.92 (m, 5H), 7.15(m, 5H). Mn, NMR=3223 g/mol.

MS (MALDI-TOF, m/z): calculated for (C12H18N2O2S2)5(C7H11O2)10(SiO1.5)10 [Mr·H]+: 3224.10 Da, Found:3224.42 Da.

Figure S3. 1H NMR of T10(5-5)

1.1.3 Synthesis of linear copolymer PDMA-b-PMA

N, N-(dimethylamine)ethyl methacrylate (DMA, 15.7g, 0.1 mol), DTTC (0.364

g, 1 mmol), 2, 2-azobisisobutyronitrile (AIBN, 0.0164g, 0.1 mmol) were dissolved in

dry 1, 4-dioxane (10 mL) in Schlenk tube, and the resulting solution was quickly

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subjected to three freeze-pump-thaw cycles, with subsequent stirring for 4 h at 70 °C.

The flask was frozen in liquid nitrogen to terminate the polymerization and thawing in

warm water (50 oC). Subsequently, the reaction mixture was precipitated in a large

excess of petroleum ether and isolated by centrifugation. The precipitation was

dissolved in THF (20 mL), and the resulting solution was purified by dialysis against

THF for 1 days. Then, THF was pumped out, and a yellow solid (PDMA, 9.5 g, 61%)

was obtained by drying 48 h at 30 oC in vacuo.

PDMA (8.5 g, 0.6 mmol), methacrylate (MA, 2.58g, 0.03 mol), AIBN (0.0164 g,

0.1 mmol) were dissolved in dry 1, 4-dioxane (36 mL) in Schlenk tube, and the

resulting solution was quickly subjected to three freeze-pump-thaw cycles, with

stirring for 4 h at 70 oC. The flask was frozen in liquid nitrogen to terminate the

polymerization and thawed in warm water. Subsequently, the reaction mixture was

precipitated in a large excess of petroleum ether and isolated by centrifugation. The

precipitate was then dissolved in THF (20mL), and the resulting solution was purified

by dialysis against THF for 2 days. After pumping out the solvent, a yellow solid

(PDMA-b-MA, 6.0 g, 65%) was obtained by drying 48 h at 30 oC in vacuo.

SEC: Mn, SEC=13.9 kg/mol, Mw, SEC=17.4 kg/mol, PDI=1.25.

FTIR (KBr, νmax/cm−1): 1152 (C−O−C), 1723 (C=O).1H NMR (CDCl3, δ/ppm): 3.76−4.42 (m, 180H), 3.61−3.69 (s, 27H), 3.25−3.39

(t, 2H), 2.51−2.63 (m, 183H), 2.20 (s, 540H), 1.58−2.12 (m, 180H), 0.70−1.21 (s,

272H).

Mn, NMR =N(h)× Mn (DMA)2

+N(m)×Mn (MA)3

+Mn (DTTC ) (1)

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Figure S4. 1H NMR of PDMA-b-PMA

1.1.4 Synthesis of linear copolymer PDMA-b-PMA-Th

Macromolecular RAFT agent (PDMA-Th). DMA (15.7g, 0.1 mol), DTTC-Th

(0.474 g, 1 mmol), AIBN (0.0164g, 0.1 mmol) were dissolved in dry 1, 4-dioxane (10

mL) in Schlenk tube, and the resulting solution was quickly subjected to three freeze-

pump-thaw cycles, with subsequent stirring for 4 h at 70 °C. The flask was frozen in

liquid nitrogen to terminate the polymerization and thawing in warm water (50 oC).

Subsequently, the reaction mixture was precipitated in a large excess of petroleum

ether and isolated by centrifugation. The precipitation was dissolved in THF (20 mL),

and the resulting solution was purified by dialysis against THF for 1 days. Then, THF

was pumped out, and a yellow solid (PDMA-Th, 10.0 g, 65%) was obtained by drying

48 h at 30 oC in vacuo.

PDMA-Th (10.0 g, 0.6 mmol), methacrylate (MA, 2.58g, 0.03 mol), AIBN

(0.0164 g, 0.1 mmol) were dissolved in dry 1, 4-dioxane (36 mL) in Schlenk tube, and

the resulting solution was quickly subjected to three freeze-pump-thaw cycles, with

stirring for 4 h at 70 oC. The flask was frozen in liquid nitrogen to terminate the

polymerization and thawed in warm water. Subsequently, the reaction mixture was

precipitated in a large excess of petroleum ether and isolated by centrifugation. The

precipitate was then dissolved in THF (20mL), and the resulting solution was purified

by dialysis against THF for 2 days. After pumping out the solvent, a yellow solid

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(PDMA-b-MA-Th, 7.0 g, 70%) was obtained by drying 48 h at 30 oC in vacuo.

SEC: Mn, SEC=16.1 kg/mol, Mw, SEC=20.5 kg/mol, PDI=1.27.

FTIR (KBr, νmax/cm−1): 1151 (C−O−C), 1721 (C=O).1H NMR (CDCl3, δ/ppm): 6.82 (m, 1H), 6.90 (m, 1H), 7.10 (m, 1H), 3.96−4.14

(m, 230H), 3.61−3.70(s, 39H), 3.28−3.34 (t, 2H), 3.09−3.14 (t, 2H), 2.52−2.63 (m,

233H), 2.28 (s, 698H), 0.72−1.2 (s, 347H).

Mn, NMR =N(h)× Mn (DMA)2

+N(m)×Mn (MA)3

+ Mn (DTTC-Th ) (2)

Figure S5. 1H NMR of PDMA-b-PMA-Th

1.1.5 Synthesis of T10-(PDMA-b-PMA)-Th copolymer precursor (M5-5)

The flexible arm PDMA-b-MA was achieved via reversible addition–

fragmentation transfer (RAFT) polymerization, regulated by the RAFT agent DTTC.

PDMA-b-MA solution was prepared by dissolving PDMA-b-MA (7.5 g, 0.5

mmol) in dry 1, 4-dioxane (36 mL) in Schlenk tube, and the solution was quickly

subjected to three freeze-pump-thaw cycles. Then, propylamine (PA, 0.411 mL, 5

mmol), Tri-N-butylphosphine (PBu3, 1.04 mL, 5 mmol) were injected by syringe

under argon atmosphere into the solution, and the mixture was degassed by three

freeze-pump-thaw cycles again. The reaction was executed for 4 hours at 40 oC under

stirring. Subsequently, the solvent removal process was executed to remove unreacted

PA for 2 times

Next, degassed T10(5-5)/TEA/dioxane solution, which was prepared by

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dissolving T10(5-5) (0.3221g, 0.1 mmol) and triethylamine (TEA, 0.505 mL, 5 mmol)

in deoxidized 1, 4-dioxane (30 mL), was injected into the tube under argon

atmosphere and the reaction was carried out for 24 h at 40 oC under stirring. After

solvent removal process, the mixture was redissolved in CH2Cl2 (10 mL) and

precipitated in cold diethyl ether/petroleum ether (180 mL, V/V=1/5) under magnetic

stirring. The precipitate was filtered off, dissolved in THF (20 mL), and the resulting

solution was purified by dialysis against THF for 2 days. Then, THF was pumped out,

and a faintly yellow solid (M5-5, 5.5 g, 75%) was obtained by drying 48 h at 30 oC in

vacuo.

SEC: Mn, SEC=37.4 kg/mol, Mw, SEC=80.5 kg/mol, PDI=2.15.

FTIR (KBr, νmax/cm−1): 1151(C−O−C), 1653 (O=C−NH), 1725 (C=O), 3259

(N−H).1H NMR (CDCl3, δ/ppm): 6.82 (m, 5H), 6.90 (m, 5H), 7.10 (m, 5H), 3.42−3.70

(m, 135H), 3.71−4.20 (s, 907H), 2.51−2.64 (s, 908H)

Mn, NMR =N(h)× Mn (DMA)2

+N(m)×Mn (MA)3

+ Mn (T 10 (5-5) ) (3)

Figure S6. 1H NMR of M5-5

1.1.6 Synthesis of the star-shaped conjugated copolymer T10-(PDMA-b-PMA)-

PEDOT (P5-5) and the linear analogue PDMA-b-PMA-b-PEDOT

M5-5 (0.1 g, 1.3×10−3 mmol) (or PDMA-b-PMA-Th (0.1 g, 5×10−3 mmol)) was

dissolved in HCl solution (3.5 mL, 1 mol/L), FeCl3 aqueous solution (1.5 mL, 0.1

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mol/L) was added as catalyst, and tetrahydrofuran (THF, 0.5 mL) was injected to

promote the emulsification of copolymer precursor. 3, 4-ethylenedioxythiophene

(EDOT)/butanol solution (10 mL, 0.02 mol/L) was carefully layered along the walls

of a vial onto the aqueous phase.

The interface reaction was proceeding for 2 days at room temperature. Then, the

aqueous phase was decanted and centrifuged at 12500 rad/min for 5 mins. The

supernatant liquid was dropwise added to the NaHCO3/THF mixture (15 mL 1 mol/L

NaHCO3 aqueous solution/45 mL THF) with rapid agitation for 1 h. When no visible

gas bubbles escaped from the mixture, the mixture was allowed to continue to stir for

0.5 h and then stand for 2 h. A clear brownness solution was obtained by filtration of

uppermost liquid phase (pH>8), concentrated, and precipitated in cool petroleum ether

(PE). The precipitate was filtered off, dissolved in THF/water solution (5 mL, volume

ratio=4/1), and the resulting solution was purified by dialysis against THF/water

(volume ratio=4/1) for 2 days. Finally, the solvent was pumped out, and a brownness

solid (P5-5, 0.05g, 50%) (or PDMA-b-PMA-b-PEDOT, 0.06 g, 60%) was obtained by

drying 48 h at 30 oC in vacuo.

P5-5 data:

SEC: Mn, SEC=40.6 kg/mol, Mw, SEC=90.5 kg/mol, PDI=2.23.

FTIR (KBr, νmax/cm−1): 1150 (C−N), 1730 (C=O).

1H NMR (CDCl3, δ/ppm): 7.00 (m, 5H), 7.06 (m, 5H), 3.40−3.72 (m, 135H),

3.78−4.70 (s, 1260H), 2.51−2.62 (s, 928H).

DPEDOT = [N (α+β+h )−N(i) ]4×5

(3)

Mn, NMR =N(i)×Mn (DMA)2

+N(m)× Mn(MA)3

+ Mn ( T 10 (5-5) )+[N (α+β+h )−N(i) ]×Mn (EDOT)4

(4)

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Figure S7. 1H NMR of P5-5

PDMA-b-PMA-b-PEDOT data:

SEC: Mn, SEC=17.9 kg/mol, Mw, SEC=22.4 kg/mol, PDI=1.31.

FTIR (KBr, νmax/cm−1): 1152 (C−N), 1728 (C=O).

1H NMR (CDCl3, δ/ppm): 4.42−3.78 (m, 257H), 3.56−3.67 (s, 39H), 2.52−2.78 (s,

233H), 2.30 (s, 698H), 0.72−1.09 (s, 346H).

DPEDOT = [N (α+β+h )−N(i) ]4

(5)

Figure S8. 1H NMR of PDMA-b-PMA-b-PEDOT

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1.2 General Procedure for obtaining the pristine SWNTs, SWNTs dispersion,

modified SWNTs and supernatant liquid

All modifiers were dissolved in THF/water solution and stirred for 24 h to ensure

the system reached equilibrium (1 mg/mL, v/v=4/1). The SWNTs were treated by

ultrasonication in acetone for 10 min at 180 W, rinsed with THF/water solution for

several times to remove organic residues and part of inorganic impurity and dried in

vacuo.

The dispersion liquid was prepared by mixing treated-SWNTs and modifier

solutions with initial mass ratio of 1:1 modifier/SWNTs in a flask and then sonicated

the resulting mixture for 20 min. All sonication processes were carried out with a horn

sonicator. The output power was fixed at 180 W and the flask is placed in a bath of

ice water during sonication to prevent the temperature rising. Then, the dispersions

were centrifuged at a speed of 12500 rpm for 10 min. The modified nanotubes were

obtained by washing and vacuum drying the residues. The centrifugal supernatant

liquid and the washing liquid (the total volume of washing liquid was four times as

much as the volume of dispersion) were merged for further testing.

1.3 Synthesized of PEDOT homopolymer by interfacial polymerization

The EDOT/butanol solution (10 mL, 0.012 mol/L) was carefully layered over

5mL FeCl3 solution (0.03 mol/L with 3 drops concentrated HCl), then the interface

reaction was proceeding for 2 days at room temperature. Finally, the precipitate in

aqueous phase was extracted, washed with water and THF for several times, dried 48h

at 30 oC in vacuo.

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Figure S9 FTIR spectroscopy of PDMA-b-PMA-Th, PDMA-b-PMA-b-PEDOT and M5-5.The absorption bands of Carbon−sulfur bonding within the thiophene ring occurred with maxima at 850, 966 and 1360 cm−1 in the spectra of PDMA-b-PMA-b-PEDOT and M5-5, which were attributed to the formation of PEDOT chains after oxidation; The band at 1360 cm−1, which indicates the existence of a quinoidal structure, was observed for all bulk PEDOT polymers [2]. The peak at 1180 cm just observed in M5-5 spectrum clearly indicated the participation of silsesquioxane, which was assigned to stretching vibration of Si−O−Si.

2.Additional Results

Figure S10 Absorption profiles for SWNT dispersions in an aqueous solution with modifiers. The dispersions were obtained by dispersing SWNTs in modifier THF/water solution (1 mg/mL, v/v=4/1) with initial mass ratio of 1:1 modifier/SWNTs. M1, M2, M3 denote SWNT dispersions in which SWNTs were dispersed in PDMA-b-PMA-Th, PDMA-b-PMA-b-PEDOT, P5-5 solution.

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Figure S11 Digital images of SWNT dispersions. M1, M2, M3 denote SWNT dispersions in which SWNTs were dispersed in PDMA-b-PMA-Th, PDMA-b-PMA-b-PEDOT, M5-5 solution.

100 200 300 400 500 600 7000

-5

-10

-15

-20

-25

DTG

(%/m

in)

T(oC)

PDMA-b-PMA-Th PDMA-b-PMA-b-PEDOT P5-5

Figure S12 DTG curves of PDMA-b-PMA-Th, PDMA-b-PMA-b-PEDOT and P5-5.

100 200 300 400 500 600 700

0

20

40

60

80

100

Mas

s (%

)

T(oC)

0

-2

-4

-6

-8

-10

DTG

(%/m

in)

Figure S13 TGA (up) and DTG (down) curves of the PEDOT homopolymer.

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-1.0 -0.5 0.0 0.5 1.0-0.02

-0.01

0.00

0.01

0.02

Cur

rent

Den

sity

(A/g

)

Potential(V) vs SCE

PDMA-b-PMA-b-PEDOT (100mV/s) P5-5 (100mV/s)

Figure S14 Cyclic voltammograms of PDMA-b-PMA-b-PEDOT and P5-5 at 100 mV/s.

References

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Trithiocarbonates as Highly Efficient RAFT Agents, Macromolecules, 35 (2002)

6754-6756.

[2] Y. Xiao, J.-Y. Lin, S.-Y. Tai, S.-W. Chou, G. Yue, J. Wu, Pulse

electropolymerization of high performance PEDOT/MWCNT counter electrodes for

Pt-free dye-sensitized solar cells, Journal of Materials Chemistry, 22 (2012) 19919-

19925.

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