Preparation of tunable wettability polymer (ionic liquid) brushes at rough substrate using surface initiated atom transfer radical polymerization

Article abstract of DOI:10.1590/S0103-50532011000300010

Using surface initiated atom transfer radical polymerization (ATRP), novel tunable wettability polymer (ionic liquid) brushes poly[2-(1-butylimidazolium-3- yl)ethyl methacrylate hexafluorophosphate] (PBIMH-PF₆^-) from a rough substrate modified with an initiator layer composed of 2-bromoisobutyryl bromide was prepared. Various characterization techniques including ellipsometry, static water contact angle measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) were used to characterize the films for each surface modification step. Kinetic studies revealed a linear increase in polymer film thickness with reaction time, indicating that chain growth from the surface was a controlled process with a "living" characteristic. Wetting measurements indicated that ion exchanging interactions can be used to switch surface characteristics from hydrophilicity to hydrophobicity in a reversible manner. Compared with the smooth surface of the flat substrate modified with the same polymer (ionic liquid) brushes, the rough substrate by chemical etching exhibited better hydrophobicity.

Full text of DOI:10.1590/S0103-50532011000300010

J. Braz. Chem. Soc., Vol. 22, No. 3, 478-483, 2011.
Printed in Brazil - ©2011 Sociedade Brasileira de Química
0103 - 5053 $6.00+0.00
Article
A
Preparation of Tunable Wettability Polymer (Ionic Liquid) Brushes at Rough
Substrate using Surface Initiated Atom Transfer Radical Polymerization
Kanjun Sun, Wu Yang,* Guofu Ma, Fei Wan, Jinzhang Gao, Ziqiang Lei and Hao Guo
Key Lab of Eco-environment Related Polymer Materials of MOE, College of Chemistry and
Chemical Engineering, Northwest Normal University, Lanzhou 730070, P.R. China
Através da técnica de polimerização radicalar por transferência atômica (ATRP) foram
preparadas novos polímeros tipo pente com molhabilidade ajustável (líquido iônico) de
hexafluorfosfato poli[2-(1-butilimidazolino-3-ila)etila metacrilato (PBIMH-PF6–), a partir de um
substrato bruto modificado com uma camada iniciadora composta de brometo 2-bromoisobutirila.
Várias técnicas de caracterização como elipsometria, medidas de ângulo de contato estático,
espectroscopia fotoeletrônica de raios X (XPS) e microscopia de força atômica (AFM) foram
utilizadas para caracterizar os filmes em cada etapa de modificação da superfície. Estudos cinéticos
revelaram um aumento linear na espessura do filme polimérico em função do tempo de reação,
indicando que o crescimento da cadeia a partir da superfície, é um processo cujo controle apresenta
características de polimerização “viva”.As medidas de molhabilidade indicaram que as interações
de troca iônica podem ser usadas para alterar as características da superfície de hidrofilicidade
para hidrofobicidade de forma reversível. O substrato bruto obtido por ataque químico exibiu uma
melhor hidrofobicidade quando comparado à superfície lisa do substrato plano modificado com
as mesmas cadeias poliméricas tipo pente (líquido iônico).
Using surface initiated atom transfer radical polymerization (ATRP), novel tunable
wettability polymer (ionic liquid) brushes poly[2-(1-butylimidazolium-3-yl)ethyl methacrylate
hexafluorophosphate] (PBIMH-PF6-) from a rough substrate modified with an initiator layer
composed of 2-bromoisobutyryl bromide was prepared. Various characterization techniques
including ellipsometry, static water contact angle measurements, X-ray photoelectron spectroscopy
(XPS), and atomic force microscope (AFM) were used to characterize the films for each surface
modification step. Kinetic studies revealed a linear increase in polymer film thickness with reaction
time, indicating that chain growth from the surface was a controlled process with a “living”
characteristic. Wetting measurements indicated that ion exchanging interactions can be used
to switch surface characteristics from hydrophilicity to hydrophobicity in a reversible manner.
Compared with the smooth surface of the flat substrate modified with the same polymer (ionic
liquid) brushes, the rough substrate by chemical etching exhibited better hydrophobicity.
Keywords: tunable wettability, polymer brushes, surface-initiated polymerization, ion
exchanging, rough substrate
Introduction
materials,11,12 microfabrication,13,14 and bioanalytical15 and
microfluidic devices16 with tunable properties.
Wettability is an important property of a solid surface
depending on the surface free energy and surface roughness,
and it is governed by both chemical composition and surface
structure.1-5 Recently,controlofsurfacewettabilityhasattracted
extensiveinterests6,7becauseofitswidevarietyofapplications,
such as discrete liquid droplet manipulators,8 self-clean
surfaces,9 tunableopticallenses,10 drugdeliveryandbiomimetic
Among the surface modification methods, grafting
surfaces with polymer brushes provides a versatile way to
modify surface properties,17-20 because of increasing the
graftingdensityandimmobilizedtetheringofpolymerbrushes
on a solid substrate by performing an organic reaction with
high efficiency21 including grafting a polymer chain through
a monomer covalently linked to the surface22 and from a
surface modified with polymerization initiators.23-25 Surface-
initiated atom transfer radical polymerization (ATRP) is one
*e-mail: yangw@nwnu.edu.cn

Vol. 22, No. 3, 2011
Sun et al.
479
of the most efficient grafting processes26-29 because it can be
used to polymerize a wide range of vinyl monomers, does
not require stringent conditions, and is tolerant of various
functional groups and impurities that are detrimental to
living anionic, cationic and some transition-metal-mediated
polymerizations.30
Facile tunability of physicochemical properties of ionic
liquids(ILs), particularlyimidazoliumions31,32 bearingsimple
alkyl appendages as cations, has led to intense interest in
ILs as an alternative of conventional organic solvents in a
range of synthesis, catalysis, and electrochemistry. Recent
developments include their uses for biopolymers,33 chemical
sensors for specific ions,34 determination of acidity scale,35
formation of nanosized metal particles36 and hollow metal
oxide microspheres37and so on. However, there has been little
study on poly (ionic liquid) based materials.We are currently
seeking to develop novel poly (ionic liquid) brushes modified
substrate surface. The availability of potentially hydrophobic
and hydrophilic ILs attests to the ease in the manipulation of
their physical properties.38,39
This paper aims at developing a novel and simple
way to achieve tunable wettability switching surface by
a chemical etching of the surface of silicon substrate and
following modification with polymer (ionic liquid) via
surface initiated ATRP. Reversible switching between
hydrophilicity and hydrophobicity can be achieved by
simply exchanging their counteranions. Such switchable
surfaces have potential applications in functional materials
and intelligent microfluidic switching.
The X-ray photoelectron spectroscopy (XPS) analysis was
carried out on a PHI-5702 multifunctional XPS, using AlKα
radiationastheexcitingsourceatameasurementangleof54°.
The binding energies of the target elements were determined
at a pass energy of 29.35 eV and a resolution of 0.2 eV,
using the binding energy of C1s at 284.6 eV as the reference.
Hydrogen nuclear magnetic resonance (1H NMR) spectra
were measured with an INOVA 400 MHz spectrometer with
DMSO-d6 or D2O as solvent.
Silicon rough surface construction, hydroxylation and
immobilization of the ATRP initiator
Thesmoothflatsiliconwasimmergedintofreshlyprepared
mixed acid solution (2.4 mol L-1 HF + 15.0 mol L-1 HNO3) at
roomtemperaturefor8min, thenrinsedwithplentyofdistilled
water and followed by boiling water for 10 min, then washed
using distilled water, and dried under a stream of nitrogen.
Then the rough substrate was immersed in (0.1 mol L-1)
NaOH aqueous solution for 10 min and subsequently in
(0.1 mol L-1) HNO3 for 10 min to generate surface hydroxyl
groups. The rough substrate had been washed with an excess
of distilled water and dried under a flow of nitrogen.
The hydroxylation rough substrate was put in anhydrous
methanolsolutionwhichcontained(100:5,v/v)APSforatleast
10 h to obtain chemically bonded -NH2 groups on the surface.
Thesurfacewasrinsedwithdichloromethane,driedunderaflow
ofnitrogengas. Itwasthemimmersedindrydichloromethane
contained pyridine (100:5, v/v), the polymerization initiator
2-bromoisobutyryl bromide was added dropwise at 0 °C, and
the mixture was maintained for 1 h at this temperature with
electromagneticstirring,thenkeptfor12hatroomtemperature.
The initiator modified silicon substrate was cleaned with dry
dichloromethane, and dried under a nitrogen flow. This
procedure was carried out according to a modification method
of Sun et al.40 Above procedure is shown in Scheme 1.
Experimental
Materials
Ammonia hexafluorophosphate (Aldrich, 98%),
3-aminopropyltriethoxysilane (APS, Kanto Chemical
Co.), 2,6-di-tert-butyl-4-methylphenol (Aldrich, 98%),
2-bromoisobutyryl bromide (AlfaAesar), 1-butylimidazole
and 2-chloroethanol (Aldrich, 98%), other reagents were of
analytical grades. Deionized water was used throughout.
The silicon (111) wafers were purchased from Shanghai
Wafer Work Corp.
Scheme 1. Preparation procedure of initiator-modified silicon substrate
surface.
Characterizations
The static water contact angles were determined by a
KRUSS DSA100 contact angle goniometer. The thickness
of polymer layer was measured with a spectroscopic
ellipsometer(GaertnermodelL116C). Morphologicalimages
of the substrate surfaces were obtained with an atomic force
microscope(AFM)(SeikoInstrumentsInc.)inatappingmode.
Synthesis of the ionic liquid monomer
The synthesis of the ionic liquid monomer
2-(1-butylimidazolium-3-yl)-ethyl methacrylate
hexafluorophosphate (BIMH)PF6- was performed according

480
Preparation of Tunable Wettability Polymer (Ionic Liquid) Brushes at Rough Substrate
J. Braz. Chem. Soc.
Scheme 2. Synthesic route of the ionic liquid monomer BIMH.
to slight modification procedure of Ding et al.,41 and the
synthesic route is shown in Scheme 2.
Figure 1. AFM topography and 3D image of the rough silicon substrate
surface.
Withcuprouschlorideascatalyst, thereactiontemperature
was maintained at the boiling point of the system for 70 min at
a feed ratio of 2:9 (the ratio of methacrylic acid to phosphorus
trichloride). Then obtained methacryloyl chloride and
2-chloroethanol reacts to achieve 2-chloroethyl methacrylate.
The mixture of 2-chloroethyl methacrylate, 1-butyl imidazole
and a little amount of 2,6-di-tert-butyl-4 methylphenol
was stirred at 40 °C for 48 h to yield a very viscous liquid,
2-(1-butylimidazolium3-yl)-ethylmethacrylatechloride.Then
a suspension of NH4PF6 inanhydrous acetonitrile was added
and a white precipitate appeared.After the mixture was stirred
for 48 h at room temperature, the sodium chloride precipitate
was removed by filtration, and the filtrate was concentrated.
The concentrated filtrate was diluted with methylene chloride
(250 mL) and filtered through a silica gel column. By reduced
pressure distillation methylene chloride was removed and
the ionic liquid monomer 2-(1-butylimidazolium 3-yl)-ethyl
methacrylate hexafluorophosphate was obtained as a viscous
oil.1H NMR (400 MHz, DMSO) d 8.391 (s, 1H, N−CH−N),
7.478 (s, 1H, N−CH=CH−N), 7.303 (s, 1H, N−CH=CH−N),
6.085 (s, 1H, CH2=CCH3), 5.729 (m,1H, CH2=CCH3), 4.369
(m, 2H, COO-CH2-CH2-N), 4.077 (t, 2H, COO-CH2-CH2-N),
3.872 (m, 2H, N-CH2-C3H7), 1.906 (m, 3H, CH2=CCH3),
1.741 (m, 2H, N-CH2-CH2C2H5), 1.235 (m, 2H, N-C2H4-
CH2-CH3), 0.898 (t, 3H, N-C2H4CH2-CH3); 13C NMR (400
MHz, DMSO-d6): d (ppm) 165.1 (CH2=CCH3-COO), 135.0 (N−
CH−N),134.4(CH2=CCH3-COO), 125.1(CH2=CCH3-COO), 122.9
(N−CH=CH−N), 119.5 (N−CH=CH−N), 63.1 (COO-CH2-CH2-N),
45.9 (N-CH2-C3H7), 41.5 (COO-CH2-CH2-N), 30.9 (N-CH2-CH2-
C2H5), 17.9 (N-C2H4-CH2-CH3), 16.7 (CH2=CCH3-COO ), 12.1
(N-C3H6-CH3);MS(ESI+)m/z237[M–PF6]+,(ESI–)m/z145[PF6]–;
HRMS(ESI+)Found:237.3217.Calc.for[C16H21N2]+:237.3215.
Surface morphology of rough silicon substrate is shown in
Figure 1.
Figure 1 shows that some holes of 1-3 mm have been
etched in the substrate surface.
In order to carry out surface-initiated ATRP, initiator
molecules must be at first introduced onto the substrate
surface. Figure 2 shows the typical XPS survey spectrum
and high-resolution elemental scan of Br3d and N1s, which
were recorded from the bromosilane initiator modified
silicon surface. The C1s core-level spectrum of the initiator
modified surface showed a peak at BEs of 284.4 eV. The N1s
peak at the BEs of 398.8 eV was attributed to the O=C–N
species and Br3d peak at the BEs of 70.8 eV resulted from
Br–C. These results proved that bromosilane initiator has
been successfully anchored on the silicon surface.
Preparation and characterization of PBIMH-PF6 brushes
using a surface-initiated ATRP and tunning of the
wettability by exchanging their counteranions
Copper chloride purified (0.092 mmol), 2,2-bipyridine
purified (0.184 mmol), and BIMH-PF6- (9.2 mmol) were
charged into a Bunsen flask with branch pipe, which was
then tightly sealed and degassed. Degassed acetonitrile
(1.6 mL) was added with a degassed syringe. The mixture
was bubbled with nitrogen for 15 min, and then the
beforehand prepared rough substrate modified with the
surface initiator was added. The flask was immersed in an
oil bath at 60 °C.At regular intervals, sample brushes were
taken from the flask via a nitrogen-purged, and then were
put into DMF to wash-up to remove physically absorbed
polymer chains. After the polymer brushes were placed
into a Soxhlet extractor to extract with DMF for 16 h, they
were dried in a stream of nitrogen and kept in a refrigerator.
The tuning of wettability of poly (ionic liquid) brushes
was carried out by exchanging their counteranions and
Scheme 3 showed a typical procedure for counteranion
exchanging.
Results and Discussion
Characterization of functionalized surfaces
Solution etching method was used to construct
appropriate surface roughness on silicon substrate.

Vol. 22, No. 3, 2011
Sun et al.
481
Figure 3. XPS survey spectrum and high-resolution elemental scan of
F1s, N1s and P2p of the PBIMH-PF6- modified silicon substrate surface.
Figure 2. XPS survey spectrum and high-resolution elemental scan of Br3d
and N1s of the bromosilane initiator modified silicon surface.
Cl-
-
-
PF6
Cl-
PF6
N
N
N
N
N
N
N
N
NaCl/Water
O
O
O
O
NH4PF6/water
O
O
O
O
O
O
O
O
N
N
N
N
Si
O
Si
O
Si
Si
O
O
O
O
O
O
O
O
Scheme 3. Procedure of counteranion exchange of the polymer brushes
PBIMH-PF6- and PBIMH-Cl-.
Figure 4. XPS survey spectrum and high-resolution elemental scan of
N1s, Cl2p and F1s of the PBIMH-Cl- modified silicon substrate surface.
Figure 3 and Figure 4 respectively show that the typical
XPS survey spectrum and high-resolution elemental
scan at the silicon surface modified with PBIMH-PF6
which was nearly consistent with ellipsometric result
(180 nm). Figure 6 showed that the film thickness was also
about 200 nm and the polymer brushes arrayed densely and
homogeneously on the flat substrate.
Figure 7 shows typical water droplet shapes and
corresponding contact angles (CA) on different substrates.
-
and PBIMH-Cl- brushes. In Figure 3 the peaks of F1s
(688.4 eV), O1s (533.6 eV), N1s (399.6 eV), C1s (285.6 eV),
and P2p (139.2 eV) were clearly found and the ratio of
[N]:[F]:[P] was about 2.2:6.1:1.1, which was close to
theoretical results. After exchanging their counteranions,
the peak of Cl2p (201.7 ev) appeared in Figure 4, whereas the
peak of F1s disappeared in survey spectrum, which showed
hexafluorophosphate had completely been exchanged with
chloride ion. The [Cl]:[N] ratio was about 0.9:2.0, which
was consistent with theoretical values.
Figure 5 and 6 are respectively AFM topographies of
the rough silicon substrate surface and the smooth flat
silicon substrate modified with PBIMH-PF6- polymer
brushes. Figure 5 showed that the polymer brushes had
homogeneously been grafted on silicon substrate surface
and a micro/nanometric composite structure had been
constructed. Grafted layer thickness was about 200 nm
Figure 5. AFM topography and 3D image of the rough silicon substrate
surface modified with polymer (ionic liquid) PBIMH-PF6- brushes.

482
Preparation of Tunable Wettability Polymer (Ionic Liquid) Brushes at Rough Substrate
J. Braz. Chem. Soc.
Figure 6. AFM topography and 3D image of the smooth silicon substrate
surface modified with polymer (ionic liquid) PBIMH-PF6- brushes.
Figure 8. Relationship of static water contact angle / deg, reaction time / h
and film thickness / nm. ––A: representation CA change of PBIMH-Cl-;
––B: representation CA change of PBIMH-PF6-; ––C: representation
thickness of film.
polymerization. The tunable wettability of poly (ionic
liquid) brushes can be achieved by exchanging their
counteranions. Moreover, if the same two counteranions
are sequentially replaced, the surface with tunable
wettability, reversible switching between hydrophilicity
and hydrophobicity can be easily obtained.
Supplementary Information
Supplementary data are available free of charge at
http://jbcs.sbq.org.br, as PDF file.
Figure 7. Photographs of water droplets on the polymer (ionic liquid)
brushes modified surfaces when exchanged PF6- with Cl-. (a) On the rough
silicon substrate; (b) On smooth silicon substrate.
Acknowledgments
It was found that through counteranion exchange the
surface wettability had successfully been reversed and the
rough PBIMH-PF6 brushes surface (R-Si-PBIMH-PF6)
had higher hydrophobicity than flat one (Si-PBIMH-PF6).
Figure 8 is the relationship of static water contact
angle, reaction time and film thickness (nm). From Figure
8 it was obviously seen that CA of PBIMH-PF6- brushes
increased with the reaction time but when it exceeded
24 h CA maintained a constant on the whole. However,
CA of PBIMH-Cl- brushes did not changed nearly. It was
also found that the surface wettability could be completely
tuned reversibly only by exchanging counteranions.
Figure 8 also showed that the thickness of the polymer
(ionic liquid) brushes linearly increased with the reaction
time, indicating that the polymerization reaction was a
“controlled/active” procedure.
The authors are grateful to National Natural Science
Foundation of China (20873101) and Key Subject of Gansu
Province, China for their financial supports.
References
1. Li,H.;Wang,X.;Song,Y.;Liu,Y.;Li,Q.;Jiang,L.;Zhu,D.; Angew.
Chem., Int. Ed. 2001, 40, 1743.
2. Feng,L.;Li, S.;Li, H.;Zhai,J.;Song,Y.;Jiang, L.;Zhu, D.;Angew.
Chem., Int. Ed. 2002, 41, 1221.
3. Feng, L.; Song, Y.; Zhai, J.; Liu, B.; Xu, J.; Jiang, L.; Zhu, D.
Angew. Chem., Int. Ed. 2003, 42, 800.
4. Feng, L.; Li, S.; Li,Y.; Li, H.; Zhang, L.; Zhai, J.; Song,Y.; Liu,
B.; Jiang, L.; Zhu, D.; Adv. Mater. (Weinheim, Ger.) 2002, 14,
1857.
5. Wang, R.;Hashimoto, K.;Fujishima,A.;Chikuni, M.;Kojima, E.;
Kitamura,A.; Shimohigoshi, M.;Watanabe,T.; Nature 1997, 388,
431.
Conclusion
Well-defined poly (ionic liquid) brushes with tunable
wettability were successfully produced on the surface
of rough silicon wafer by surface initiated ATRP
6. Lahann, J.; Mitragotri, S.; Tran, T.; Kaido, H.; Sundaram, J.;
Choi, I. S.; Hoffer, S.; Somorjai, G. A.; Langer, R.; Science
2003, 299, 371.

Vol. 22, No. 3, 2011
Sun et al.
483
7. Yu, X.; Wang, Z.; Jiang, Y.; Shi, F.; Zhang, X.; Adv. Mater.
(Weinheim, Ger.) 2005, 17, 1289.
26. Matyjaszewski, K.; Miller, P. J.; Shukla, N.; Immaraporn,
B.; Gelman, A.; Luokala, B. B.; Siclovan, T. M.; Kickelbick,
G. ; Vallant, T.; Hoffmann, H.; Pakula, T.; Macromolecules
1999, 32, 8716.
8. Paik, P.; Pamula, V. K.; Pollack, M. G.; Fair, R. B.; Lab Chip
2003, 3, 28.
9. Cheng, Y. T.; Rodak, D. E.; Wong, C. A.; Hayden, C. A.;
Nanotechnology 2006, 17, 1359.
27. Tsarevsky, N. V.; Matyjaszewski, K.; Chem. Rev. 2007,
107, 2270.
10. Kuiper, S.; Hendriks, B. H. W.; Appl. Phys. Lett. 2004,
85, 1128.
28. Zhang, M.; Liu, L.; Wu, C.; Fu, G.; Zhao, H.; He, B.;
Polymer 2007, 48, 1989.
11. Galaev, I. Y.; Mattiasson, B.; Trends Biotechnol. 1999,
17, 335.
29. Tang, H.; Tang, J.; Ding, S.; Radosz, M.; Shen, Y.;
J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 1432.
30. Patten, T. E.; Matyjaszewski, K.; Adv. Mater. (Weinheim,
Ger.) 1998, 10, 901.
12. Aksay, I. A.; Trau, M.; Manne, S.; Honma, I.; Yao, N.;
Zhou, L.; Fenter, P.; Eisenberger, P. M.; Gruner, S. M.; Science
1996, 273, 892.
31. Lee, S.; Chem. Commun. 2006, 1049.
13. Gleiche, M.; Chi, L. F.; Fuchs, H.; Nature 2000, 403, 173.
14. Tan, J. L.; Tien, J.; Chen, C. S.; Langmuir 2002, 18, 519.
15. Nath, N.; Chilkoti, A.; Adv. Mater. (Weinheim, Ger.) 2002,
14, 1243.
32. Lee, B. S.; Chi, Y. S.; Lee, J. K.; Choi, I. S.; Song, C. E.;
Namgoong, S. K.; Lee, S.; J. Am. Chem. Soc. 2004, 126, 480.
33. Kimizuka, N.; Nakashima, T.; Langmuir 2001, 17, 6759.
34. Ho, H. A.; Leclerc, M.; J. Am. Chem. Soc. 2003, 125,
4412.
16. Rohr, T.; Ogletree, D. F.; Svec, F.; Fréchet, J. M. J.; Adv.
Funct. Mater. 2003, 13, 264.
35. Thomazeau, C.; Olivier-Bourbiou, H.; Magna, L.; Luts,
S.; Gilbert, B.; J. Am. Chem. Soc. 2003, 125, 5264.
36. Dupont, J.; Fonseca, G. S.; Umpierre, A. P.; Fichtner, P.
F. P.; Teixeira, S. R.; J. Am. Chem. Soc. 2002, 124, 4228.
37. Nakashima, T.; Kimizuka, N.; J. Am. Chem. Soc. 2003,
125, 6386.
17. Zhao, B.; Brittain, W. J.; Prog. Polym. Sci. 2000, 25, 677.
18. Edmondson, S.; Osborne, V. L.; Huck, W. T. S.; Chem.
Soc. Rev. 2004, 33, 14.
19. Motornov, M.; Sheparovych, R.; Katz, E.; Minko, S.; ACS
Nano. 2008, 2, 41.
20. Zhou, F.; Huck, W. T. S.; Phys. Chem. Chem. Phys. 2006,
8, 3815.
38. Swatloski, R. P.; Visser, A. E.; Matthew Reichert, W.;
Broker, G. A.; Farina, L. M.; Holbrey, J. D.; Rogers, R. D.;
Chem. Commun. 2001, 2070.
21. Gao, H.; Matyjaszewski, K.; J. Am. Chem. Soc. 2007,
129, 6633.
39. He, X. Y.; Yang, W.; Pei, X. W.; Macromolecules 2008,
41, 4615.
22. Buchmeiser, M. R.; Sinner, F.; Mupa, M.; Wurst, K.;
Macromolecules 2000, 33, 32.
40. Sun, T.; Wang, G.; Feng, L.; Liu, B.; Ma, Y.; Jiang, L.;
Zhu, D.; Angew. Chem., Int. Ed. 2004, 43, 357.
41. Ding, S.; Tang, H.; Radosz, M.; Shen, Y.; J. Polym. Sci.,
Part A: Polym. Chem. 2004, 42, 5794.
23. Prucker, O.; Ruhe, J.; Macromolecules 1998, 31, 592.
24. Wu, T.; Efimenko, K.; Genzer, J.; J. Am. Chem. Soc. 2002,
124, 9394.
25. Zhai, G.; Kang, E. T.; Neoh, K. G.; Macromolecules 2004,
37, 7240.
Submitted: April 21, 2010
Published online: October 26, 2010

J. Braz. Chem. Soc., Vol. 22, No. 3, S1, 2011.
Printed in Brazil - ©2011 Sociedade Brasileira de Química
0103 - 5053 $6.00+0.00
Supplementary Information
SI
Preparation of Tunable Wettability Polymer (Ionic Liquid) Brushes at Rough
Substrate Using Surface Initiated Atom Transfer Radical Polymerization
Kanjun Sun, Wu Yang,* Guofu Ma, Fei Wan, Jinzhang Gao, Ziqiang Lei and Hao Guo
Key Lab of Eco-environment Related Polymer Materials of MOE, College of Chemistry and
Chemical Engineering, Northwest Normal University, Lanzhou 730070, P.R. China
The 13C NMR data/spectrum of ionic liquid monomer 2-(1-butylimidazolium 3-yl)-ethyl
methacrylate hexafluorophosphate.
13C NMR (400 MHz, DMSO-d6): d (ppm) 165.1 (CH2=CCH3-COO), 135.0 (N−CH−N),
134.4 (CH2=CCH3-COO), 125.1 (CH2=CCH3-COO), 122.9 (N−CH=CH−N), 119.5
(N−CH=CH−N), 63.1 (COO-CH2-CH2-N), 45.9 (N-CH2-C3H7), 41.5 (COO-CH2-CH2-N), 30.9
(N-CH2-CH2-C2H5), 17.9 (N-C2H4-CH2-CH3), 16.7 (CH2=CCH3-COO ), 12.1 (N-C3H6-CH3).
Figure S1. 13C NMR spectrrum of ionic liquid monomer 2-(1-butylimidazolium 3-yl)-ethyl methacrylate hexafluorophosphate.
*e-mail: yangw@nwnu.edu.cn