Effect of isomeric pyridine moieties in ethynylstyrene derivatives on their anionic polymerization

Article abstract of DOI:10.1002/pola.24989

The anionic polymerization behaviors of ethynylstyrene derivatives containing isomeric pyridine moieties, 2-(2-(4-vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl)ethynyl)pyridine (B), and 4-(2-(4-vinylphenyl)ethynyl) pyridine (C), were investigated in the identical conditions. The anionic polymerization of A-C was performed with (diphenylmethyl)potassium (Ph ₂CHK) in tetrahydrofuran (THF) at -78 °C. The polymerization of A proceeded quantitatively at -78 °C for 4 h, and the resulting poly(A) possessed predictable molecular weights (M_n = 3300-68,500) and narrow molecular weight distributions (MWDs) (M_w/M_n = 1.04-1.11). In contrast, the anionic polymerization of B was not performed at -78 °C for 4 h due to the occurrence of side reactions. The monomer B was quantitatively recovered after the reaction. In the polymerization of C performed at -78 °C for 6 h, observed M_n values of the resulting poly(C) were in good agreement with calculated molecular weights based on monomer to initiator ratios, but the MWDs were somewhat broad (M _w/M_n = 1.23-1.31). To estimate the reactivity of A and to characterize its living nature, the block copolymerization of A with 2-vinylpyridine (2VP) and methyl methacrylate (MMA) was performed. The well-defined block copolymers, poly(2VP)-b-poly(A) and poly(A)-b-poly(MMA), were successfully synthesized without any additives.

Full text of DOI:10.1002/pola.24989

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
Effect of Isomeric Pyridine Moieties in Ethynylstyrene Derivatives on
Their Anionic Polymerization
Beom-Goo Kang,1,2 Nam-Goo Kang,1,2 Jae-Suk Lee1,2
1School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST),
1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea
2Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology (GIST),
1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea
Correspondence to: J.-S. Lee (E-mail: jslee@gist.ac.kr)
Received 19 May 2011; accepted 1 September 2011; published online 26 September 2011
DOI: 10.1002/pola.24989
ABSTRACT: The anionic polymerization behaviors of ethynylstyr-
ene derivatives containing isomeric pyridine moieties, 2-(2-(4-
vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl)ethynyl)pyri-
dine (B), and 4-(2-(4-vinylphenyl)ethynyl)pyridine (C), were inves-
tigated in the identical conditions. The anionic polymerization of
A–C was performed with (diphenylmethyl)potassium (Ph2CHK) in
tetrahydrofuran (THF) at ꢀ78 ꢁC. The polymerization of A pro-
ceeded quantitatively at –78 ꢁC for 4 h, and the resulting poly(A)
possessed predictable molecular weights (Mn ¼ 3300–68,500) and
narrow molecular weight distributions (MWDs) (Mw/Mn ¼ 1.04–
1.11). In contrast, the anionic polymerization of B was not per-
formed at –78 ꢁC for 4 h due to the occurrence of side reactions.
The monomer B was quantitatively recovered after the reaction. In
the polymerization of C performed at –78 ꢁC for 6 h, observed Mn
values of the resulting poly(C) were in good agreement with calcu-
lated molecular weights based on monomer to initiator ratios, but
the MWDs were somewhat broad (Mw/Mn ¼ 1.23–1.31). To esti-
mate the reactivity of A and to characterize its living nature, the
block copolymerization of A with 2-vinylpyridine (2VP) and methyl
methacrylate (MMA) was performed. The well-defined block co-
polymers, poly(2VP)-b-poly(A) and poly(A)-b-poly(MMA), were
C
V
successfully synthesized without any additives. 2011 Wiley Peri-
odicals, Inc. J Polym Sci Part A: Polym Chem 49: 5199–5209, 2011
KEYWORDS: block copolymers; ethynylstyrene derivatives; gel
permeation chromatography (GPC); heteroatom-containing
polymers; isomeric pyridine moieties; living anionic
polymerization
INTRODUCTION Since Szwarc first reported the living anionic
polymerization of styrene, there have been numerous reports
of the living anionic polymerization of styrene derivatives
para-substituted with a variety of functional groups. The living
polymers could be obtained by the anionic polymerization of
styrene derivatives para-substituted with alkyl,2 alkenyl,3–5
and alkynyl6 groups without the occurrence of side reactions.
In contrast, the living anionic polymerization of styrene deriv-
atives para-substituted with heterocyclic groups was problem-
atic because the functional groups could be easily attacked by
highly reactive anionic species such as anionic initiators and
propagating chain-end carbanions.7–10
attracted significant interest because of unique properties,
which are hole-transporting properties of triphenylamine
and carbazole moieties,16–22 and hydrophilic properties of
pyridine moieties.23–26
In particular, polymers containing pyridine moieties have
received continuous attention due to the hydrophilic proper-
ties, which are contributed by the nitrogen atom on the aro-
matic ring. To date, our group has successfully synthesized
the well-defined homopolymer with pyridine moieties and
block copolymers with 2-vinylpyridine (2VP) to study their
morphological behaviors.9,23-26 For example, the micellization
behavior of the amphiphilic homopolymer poly(2-(4-vinyl-
phenyl)pyridine) and the effect of solvent composition on
the transformation of micelles to vesicles of rod-coil poly(n-
hexyl isocyanate)-b-poly(2VP) diblock copolymer were
investigated.25,26
In our group, we have been studying anionic polymerization
behaviors of methyl methacrylate (MMA) and styrene deriva-
tives.9–15 Especially, we reported that the living anionic poly-
merization of styrene derivatives para-substituted with pyri-
dine,9 triphenylamine,10 and carbazole13 moieties can be
achieved by controlling polymerization conditions (tempera-
ture, reaction time, additive, and initiator) or introducing
protecting group. In recent years, these polymers have
In addition, there have been considerable interests in the
synthesis of polymers with ethynyl groups because these are
highly useful materials that can be thermally crosslinked and
can also provide interesting five-membered heterocycles by
Additional Supporting Information may be found in the online version of this article.
C
V
2011 Wiley Periodicals, Inc.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5199

ARTICLE
WWW.POLYMERCHEMISTRY.ORG
CHART 1 Summary of anionic polymerization of A–C with Ph2CHK in THF at ꢀ78 ꢁC.
click reactions with azide groups.27–31 Ishizone et al.6,32,33
actually performed the anionic polymerization of 4-ethynyl-
styrene derivatives para-substituted with tert-butyl, trimeth-
ylsilyl, and phenyl groups with sec-butyllithium and oligo
(a-methylstyryl)dipotassium in tetrahydrofuran (THF) at
ꢀ78 ꢁC. They reported that the polymerizations proceeded
quantitatively for 0.5 h without any side reactions, and well-
defined polymers with predictable molecular weights and
narrow molecular weight distributions (MWDs) were
obtained.
EXPERIMENTAL
Materials
4-Bromostyrene (Aldrich, 98%), 2-ethynylpyridine (Aldrich,
98%), 3-ethynylpyridine (Aldrich, 98%), 4-ethynylpyridine
hydrochloride (Aldrich, 97%), copper(I) iodide (Aldrich,
99.999%), triphenylphosphine (Aldrich, 99%), and bis(tri-
phenylphosphine)palladium(II) chloride (Tokyo Chemical
Industry) were used without further purification. Triethyl-
amine (Aldrich, ꢂ99.5%) was distilled from calcium hydride
(CaH2) under vacuum. 2VP and MMA were passed through
an alumina column, washed with an aqueous 5% sodium
hydroxide (NaOH) solution, and then dried over anhydrous
sodium sulfate (Na2SO4) for 24 h. These were distilled from
CaH2 under vacuum and then further distilled from CaH2 on
a vacuum line. The monomers were diluted with THF and
sealed in ampoules with break-seals on a vacuum line. THF
used for polymerization was refluxed over sodium for 5 h
and then distilled from a sodium naphthalenide solution on
a vacuum line.
Furthermore, studies on the living anionic polymerization of
positional isomers of para-substituted styrene derivatives,
ortho- and meta-substituted styrene derivatives, have been
performed to demonstrate the positional effects of the sub-
stituent on polymerization behavior. To investigate the posi-
tional effects of the substituent, Nakahama and coworkers
performed the anionic polymerization of three positional iso-
mers (ortho, meta, and para) of styrenes substituted with
(trimethylsilyl)ethynyl,32,33 fluoro,34 1,3-dioxolane,35 N-cyclo-
hexylimino,36,37 and cyano38,39 groups. In all cases, they
observed that anionic polymerization behaviors have been
determined by the position of the substituent. For instance,
the styrene monomer para-substituted with a cyano group
underwent living anionic polymerization, but the living ani-
onic polymerizations of ortho- and meta-substituted isomers
were not successful. It has been suggested that the positional
effect of the substituent is a crucial factor for achieving the
living anionic polymerization of substituted styrene isomers.
Measurements
Monomers and polymers were identified by H and 13C NMR
1
spectroscopy (JEOL JNM-ECX400) at 25 ꢁC using CDCl3 as a
solvent. Chemical shifts were calculated in reference to tetra-
methylsilane at 0 ppm. Elemental analyses were performed
by the Busan Center of the Korea Basic Science Institute
(Vario-EL III, Elementar Analysensysteme GmbH). Molecular
weights of the polymers were measured using size exclusion
chromatography (SEC, Waters M77251, M510) with four col-
umns (HR 0.5, HR 1, HR 3, and HR 4, Waters Styragel
columns run in series; the pore size of the columns was 50,
100, 1000, and 10,000 Å, respectively) with a refractive
index detector at a flow rate of 1 mL/min using THF con-
taining 2% triethylamine as the eluent at 40 ꢁC and cali-
brated with styrene standards (American Polymer Standards
Corp.). The Fourier transform infrared (FTIR) spectra were
obtained from Perkins-Elmer Spectrum 2000 using KBr
pellets. Thermal properties were investigated using thermo-
gravimetric analysis (TGA, TA Instrument (TGA-Q50)) and
differential scanning calorimetry (DSC, TA Instrument (DSC-
In this study, we have prepared functional ethynylstyrene
derivatives containing isomeric pyridine moieties, 2-(2-(4-
vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl)ethy-
nyl)pyridine (B), and 4-(2-(4-vinylphenyl)ethynyl)pyridine
(C), and the anionic polymerization of A–C has been
performed to obtain well-defined polymers because, as
aforementioned, ethynylpyridine moieties possess attractive
functionalities. Herein, we mainly described that isomeric
pyridine moieties significantly influenced polymerization
behaviors of A–C (Chart 1). Additionally, the block copoly-
merization of A with 2VP and MMA was performed to esti-
mate the reactivity of A and the nucleophilicity of living
poly(A).
ꢁ
Q20)) at a heating rate of 10 C/min under nitrogen.
5200
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
24 h under nitrogen (Scheme 1). The residue was purified
by silica column chromatography with diethyl ether
and n-hexane (3:7) and subsequently recrystallized from
n-hexane to give a white solid (1.62 g, 7.89 mmol, 73%).
1H NMR (400 MHz, CDCl3): d ¼ 5.31–5.34 (d, 1H, CH2¼¼
trans, J ¼ 11.0 Hz), 5.78–5.83 (d, 1H, CH2¼¼ cis, J ¼ 17.6 Hz),
6.69–6.76 (dd, 1H, ¼¼CH trans, J ¼ 11.0 Hz and 17.6 Hz),
7.26–7.30 (m, 1H, pyridine), 7.40–7.52 (m, 4H, phenyl),
7.80–7.82 (m, 1H, pyridine), 8.54–8.56 (m, 1H, CHAN of pyr-
idine), 8.76–8.77 (m, 1H, CH¼¼N of pyridine). 13C NMR (100
MHz, CDCl3): d ¼ 86.6, 92.7, 115.2 (CH2¼¼), 120.5, 121.8,
123.0, 126.3, 131.9, 136.1, 138.0, 138.4, 148.6, 152.3. FTIR
(KBr, cmꢀ1): 3053, 2219 (CBC), 1626, 1559, 1476, 1409,
1114, 1022, 990, 910, 845. Anal. Calcd for C15H11N: C,
87.77; H, 5.40; N, 6.82. Found: C, 86.54; H, 5.09; N, 6.58.
SCHEME 1 Synthesis of 2-(2-(4-vinylphenyl)ethynyl)pyridine
(A), 3-(2-(4-vinylphenyl)ethynyl)pyridine (B), and 4-(2-(4-vinyl-
phenyl)ethynyl)pyridine (C).
Initiators
4-(2-(4-Vinylphenyl)ethynyl)pyridine (C)
The synthesis of (diphenylmethyl)potassium (Ph2CHK) was
performed by the reaction of potassium naphthalenide (K-
Naph) and a 1.5 M excess of diphenylmethane in dry THF at
room temperature for 3 days. The initiator solution was
stored at ꢀ30 ꢁC in ampoules equipped with break-seals.
The initiator efficiency was measured by titration with octyl-
alcohol in a sealed reactor under vacuum.
The same procedure was followed, as described above for A,
using 4-bromostyrene (5.00 g, 27.3 mmol), 4-ethynylpyridine
hydrochloride (5.33 g, 38.2 mmol), copper(I) iodide (0.210 g,
1.07 mmol), triphenylphosphine (0.350 g, 1.35 mmol), dry
triethylamine (50 mL), and bis(triphenylphosphine)palladiu-
m(II) chloride (0.370 g, 0.530 mmol). The mixture was
stirred at 80 ꢁC for 24 h under nitrogen (Scheme 1). The
residue was purified by silica column chromatography with
diethyl ether and n-hexane (3:7) and subsequently recrystal-
lized from n-hexane to give a white solid (1.74 g, 8.46 mmol,
31%). 1H NMR (400 MHz, CDCl3): d ¼ 5.33–5.36 (d, 1H,
CH2¼¼ trans, J ¼ 11.0 Hz), 5.79–5.84 (d, 1H, CH2¼¼ cis, J ¼
17.6 Hz), 6.69–6.76 (dd, 1H, ¼¼CH trans, J ¼ 11.0 Hz and
17.6 Hz), 7.37–7.43 (m, 4H, phenyl), 7.50–7.52 (d, 2H, pyri-
dine), 8.59–8.61 (m, 2H, CHAN and CH¼¼N of pyridine). 13C
NMR (100 MHz, CDCl3): d ¼ 87.2, 94.1, 115.4 (CH2¼¼), 121.2,
125.5, 126.3, 131.4, 132.1, 136.0, 138.4, 149.8. FTIR (KBr,
cmꢀ1): 3045, 2223 (CBC), 1624, 1591, 1508, 1411, 1111,
1015, 988, 921, 827. Anal. Calcd for C15H11N: C, 87.77; H,
5.40; N, 6.82. Found: C, 86.56; H, 5.47; N, 6.38.
2-(2-(4-Vinylphenyl)ethynyl)pyridine (A)
A solution of 4-bromostyrene (5.00 g, 27.3 mmol), 2-ethynyl-
pyridine (3.94 g, 38.2 mmol), copper(I) iodide (0.210 g, 1.07
mmol), and triphenylphosphine (0.350 g, 1.35 mmol) in dry
triethylamine (50 mL) was bubbled with nitrogen for 1 h at
room temperature. Bis(triphenylphosphine)palladium(II)
chloride (0.370 g, 0.530 mmol) was added to the solution,
ꢁ
and the mixture was stirred at 80 C for 24 h under nitrogen
(Scheme 1). The crude mixture was cooled to room tempera-
ture. The reaction mixture was filtered and then concen-
trated under vacuum. The residue was dissolved in n-hexane
and washed with 2 N HCl and water. The organic solution
was dried over anhydrous Na2SO4 and filtered. After evapo-
ration of the solvent, the residue was purified by silica col-
umn chromatography with diethyl ether and n-hexane (3:7)
and subsequently recrystallized from n-hexane to give a
white solid (1.68 g, 8.19 mmol, 30%). 1H NMR (400 MHz,
CDCl3): d ¼ 5.31–5.34 (d, 1H, CH2¼¼ trans, J ¼ 11.0 Hz),
5.78–5.82 (d, 1H, CH2¼¼ cis, J ¼ 17.6 Hz), 6.68–6.75 (dd, 1H,
¼¼CH trans, J ¼ 11.0 Hz and 17.6 Hz), 7.25–7.68 (m, 7H, phe-
nyl and pyridine), 8.62–8.63 (m, 1H, CH¼¼N of pyridine). 13C
NMR (100 MHz, CDCl3): d ¼ 89.3, 115.2 (CH2¼¼), 121.5,
122.7, 126.2, 127.1, 132.3, 136.2, 138.1, 143.5, 150.1. FTIR
(KBr, cmꢀ1): 3049, 2220 (CBC), 1625, 1560, 1465, 1427,
1151, 1001, 988, 923, 840. Anal. Calcd for C15H11N: C,
87.77; H, 5.40; N, 6.82. Found: C, 88.20; H, 5.42; N, 6.78.
Purification of Monomers
After silica column chromatography and repeated recrystalli-
zation of A–C, the monomers were freeze-dried from their
benzene solutions under reduced pressure for 12 h and then
dried over phosphorus(V) oxide (P2O5) at room temperature
for 24 h in a glass apparatus equipped with break-seals on a
vacuum line. Tꢁhe monomers were diluted with dry THF and
stored at ꢀ30 C in glass ampoules under high vacuum.
Anionic Polymerization of A
The anionic polymerization of
A
was perforꢀm6ed with
ꢁ
Ph2CHK in THF at ꢀ78 C under high vacuum (10 Torr) in
all-glass reactors equipped with break-seals. The reactor was
prewashed with the initiator solution before polymerization.
The orange color of Ph2CHK was immediately changed to
deep blue after addition of A to initiator solution. The color
was obviously maintained during polymerization. The reac-
tion was terminated with methanol, and the reaction solution
was poured into a large amount of n-hexane to precipitate
polymer. The polymer was reprecipitated in THF/n-hexane
and freeze-dried from the benzene solution under reduced
3-(2-(4-Vinylphenyl)ethynyl)pyridine (B)
The same procedure was followed, as described above for A,
using 4-bromostyrene (2.00 g, 10.9 mmol), 3-ethynylpyridine
(1.60 g, 15.3 mmol), copper(I) iodide (0.083 g, 0.430 mmol),
triphenylphosphine (0.140 g, 0.540 mmol), dry triethylamine
(20 mL), and bis(triphenylphosphine)palladium(II) chꢁloride
(0.150 g, 0.210 mmol). The mixture was stirred at 80 C for
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5201

ARTICLE
WWW.POLYMERCHEMISTRY.ORG
40.0–42.0
(CH2ACH),
88.3
(pyridineACBC),
89.5
(pyridineACBC), 119.8, 122.4, 127.3, 127.7, 127.9, 131.9,
136.0, 143.7, 149.9 (phenyl and pyridine). FTIR (KBr, cmꢀ1):
3,027, 2,926, 2,221 (CBC), 1,582, 1,562, 1,506, 1,428, 1,156,
1,018, 989, 833.
Anionic Polymerization of B
The same polymerization procedure was followed, as
described above for anionic ꢁ polymerization of A, using
Ph2CHK in THF at ꢀ78 and 0 C. The colors of the polymer-
ꢁ
ization solutions were deep violet at ꢀ78 C and deep red at
ꢁ
0 C, respectively. These distinct colors were obviously main-
tained during polymerization. The polymer was reprecipi-
tated in THF/n-hexane and freeze-dried from the benzene
solution under reduced pressure for characterization. The
resulting polymer was characterized using 1H and 13C NMR
1
and FTIR. Poly(B); H NMR (400 MHz, CDCl3): d ¼ 1.25–2.18
(3H, CH2ACH), 6.31–7.82 (6H, phenyl and pyridine), 8.47
(1H, CHAN of pyridine), 8.69 (1H, CH¼¼N of pyridine). 13C
NMR (100 MHz, CDCl3): d ¼ 40.0–42.0 (CH2ACH), 85.7
(pyridineACBC), 92.6 (pyridineACBC), 120.4, 123.0, 127.6,
127.9, 131.6, 131.7, 138.2, 148.4, 152.0 (phenyl and pyri-
dine). FTIR (KBr, cmꢀ1): 3028, 2925, 2219 (CBC), 1583,
1561, 1508, 1408, 1188, 1022, 950, 832.
FIGURE 1 1H NMR spectra of (a) A and (b) poly(A) in CDCl3.
pressure for characterization. The characterization of result-
ing polymer was performed using 1H and 13C NMR and
FTIR. Poly(A); 1H NMR (400 MHz, CDCl3): d ¼ 1.26–2.17
(3H, CH2ACH), 6.52–7.49 (7H, phenyl and pyridine), 8.54
(1H, CH¼¼N of pyridine). 13C NMR (100 MHz, CDCl3): d ¼
Anionic Polymerization of C
The same polymerization procedure was followed, as
described above for anionic polymerization of A, using
TABLE 1 Anionic Polymerization of A–C With Ph2CHK in THF
Mn ꢃ 10ꢀ3
Monomer
(mmol)
Initiator
(mmol)
Temp
(ꢁC)
Time
(h)
Yield
(%)
[M]/[I]a
Calcdb
Obsdc
Mw/Mn
c
Run
1
A, 0.764
A, 2.10
A, 1.99
A, 0.837
A, 0.753
A, 0.982
A, 2.19
A, 4.47
B, 0.500
B, 1.04
0.0140
0.0764
0.0195
0.0551
0.0225
0.0198
0.0226
0.0141
0.0202
0.0174
0.0140
0.0296
0.0175
0.0141
0.0355
0.0147
0.0215
55
27
102
15
33
50
97
317
25
60
69
21
91
67
38
44
35
–78
–78
–78
–78
–78
–78
–78
–78
–78
–78
0
0.5
1
6.4
4.2
6.8
3.3
1.07
1.06
1.05
1.06
1.07
1.09
1.04
1.11
1.90
2.42
1.23d
1.16d
1.19d
1.26
1.23
1.31
57.3
74.4
83.5
100
100
100
100
100
9.8
2
3
2
17.5
3.1
19.2
3.3
4
4
5
4
6.9
7.2
6
4
10.3
19.9
65.1
0.5
10.7
20.3
68.5
17.6
69.5
11.0
5.0
7
4
8
4
9
4
10
11
12
13
14
15
16
17
a
24
1
1.2
9.4
B, 0.966
B, 0.626
B, 1.60
10.2
4.3
72.0
100
100
77.7
100
100
45.8
0
2
0
2
18.8
10.6
7.8
20.8
11.1
8.1
C, 0.940
C, 1.35
–78
–78
–78
0
4
6
C, 0.643
C, 0.747
6
9.0
9.8
e
2
3.3
3.5
–
d
e
Calculated from the feed ratio of the initiator and monomer.
M
w/Mn of main peak.
The Mw/Mn was bimodal, presumably due to the intermolecular side
reaction.
b
Mn (calcd) ¼ (molecular weight of monomer) ꢃ [monomer]/[initiator]
ꢃ yield.
c
Mn(obsd) and Mw/Mn were obtained by size exclusion chromatogra-
phy calibration with polystyrene standards in THF solution containing
2% triethylamine as the eluent at 40 ꢁC.
5202
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
ꢁ
Ph2CHK in THF at ꢀ78 and 0 C. When C was added to the
initiator solution, the color of Ph2CHK turned to deep blue at
ꢀ78 ꢁC and navy blue at 0 ꢁC, respectively. These distinct
colors were obviously maintained during polymerization.
The polymer was reprecipitated in THF/n-hexane and
freeze-dried from the benzene solution under reduced pres-
sure for characterization. The resulting polymers were char-
acterized by means of 1H and 13C NMR and FTIR. Poly(C);
1H NMR (400 MHz, CDCl3): d ¼ 1.26–2.18 (3H, CH2ACH),
6.42–7.52 (6H, phenyl and pyridine), 8.51 (2H, CHAN and
CH¼¼N of pyridine). 13C NMR (100 MHz, CDCl3): d ¼ 40.0–
42.0 (CH2ACH), 86.6 (pyridineACBC), 93.7 (pyridineACBC),
119.8, 125.3, 127.4, 127.6, 131.2, 131.8, 149.8 (phenyl and
pyridine). FTIR (KBr, cmꢀ1): 3,028, 2,924, 2,220 (CBC),
1,592, 1,542, 1,510, 1,408, 1,215, 1,018, 989, 820.
Block Copolymerization
The first-stage polymerꢁization of 2VP was performed with
Ph2CHK in THF at ꢀ78 C for 0.5 h under high vacuum con-
dition (10ꢀ6 Torr). After sampling for characterization of pol-
y(2VP), A was added into the living poly(2VP) solution and
the reaction continued at ꢀ78 ꢁC for 4 h. Both poly(2VP)
and block copolymer were quantitatively obtained after ter-
mination with methanol. In the block copolymerization of A
with MMA, MMA was added to the living poly(A) solution
ꢁ
and the reaction continued at ꢀ78 C for 0.5 h after prepara-
ꢁ
tion of living poly(A) with Ph2CHK in THF at ꢀ78 C for 4 h.
The resulting block copolymers were characterized by 1H
NMR and FTIR. Poly(2VP)-b-poly(A); 1H NMR (400 MHz,
CDCl3): d ¼ 1.27–1.83 (CH2ACH of poly(2VP) and poly(A)),
2.21–2.40 (CH2ACH of poly(2VP)), 6.19–7.60 (phenyl and
pyridine poly(2VP) and poly(A)), 8.16–8.36 (CH¼¼N of pol-
y(2VP)), 8.53 (CH¼¼N of poly(A)). FTIR (KBr, cmꢀ1): 3,005,
2,932, 2,221 (CBC), 1,592, 1,570, 1,508, 1,474, 1,435, 1,150,
994. Poly(A)-b-poly(MMA); 1H NMR (400 MHz, CDCl3): d ¼
0.70–2.12 (CH2ACH of poly(A) and CH2AC(CH3) of poly
(MMA)), 3.60 (OCH3 of poly(MMA)), 6.51–7.52 (phenyl and
pyridine of poly(A)), 8.53 (CH¼¼N of poly(A)). FTIR (KBr,
cmꢀ1): 2,995, 2,951, 2,222 (CBC), 1,730 (C¼¼O), 1,583,
1,561, 1,508, 1,464, 1,388, 1,242, 1,193, 1,150, 989, 839,
779, 753.
RESULTS AND DISCUSSION
Living Anionic Polymerization of A
FIGURE 2 SEC curves of (a) poly(A) synthesized with Ph2CHK
in THF at ꢀ78 ꢁC for 4 h (Table 1, run 7): Mn(obsd) ¼ 20,300,
Mw/Mn ¼ 1.04, (b) polymeric product produced by the anionic
polymerization of B with Ph2CHK in THF at ꢀ78 ꢁC for 4 h (Ta-
ble 1, run 9): Mn(obsd) ¼ 17,600, Mw/Mn ¼ 1.90, and (c) poly(C)
synthesized with Ph2CHK in THF at ꢀ78 ꢁC for 6 h (Table 1, run
16): Mn(obsd) ¼ 9800, Mw/Mn ¼ 1.31.
First, the anionic polymerization of A was performed with
ꢁ
Ph2CHK in THF at ꢀ78 C for 0.5–4 h. After addition of A to
the solution of Ph2CHK, the color of polymerization solution
became deep blue (Fig. S3 in the Supporting Information).
This color that indicates propagating carbanion of living
poly(A) was maintained during polymerization. The yield
increased from 57.3 to 100% with increasing polymerization
1
time from 0.5 to 4 h. The H NMR spectra shown in Figure 1
All SEC curves of the resulting poly(A) were unimodal and
the polydispersity indices, Mw/Mn, were ꢄ1.10. Furthermore,
observed Mn values determined by SEC were in good agree-
ment with calculated molecular weights based on monomer
to initiator ratios. For example, the polymerization proceeded
quantitatively with Ph2CHK for 4 h (Table 1, run 7). As illus-
trated in Figure 2(a), the SEC profile showed a unimodal and
illustrate that the polymerization reaction proceeded exclu-
sively because the vinyl peak of A vanished while the broad
peak of the main polymer chain and the broad characteristic
HC¼¼N peak of the pyridine unit appeared at 1.26–2.17 and
8.54 ppm, respectively. The anionic polymerization results
for A are summarized in Table 1.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5203

ARTICLE
WWW.POLYMERCHEMISTRY.ORG
SCHEME 2 Living anionic polymerization of A with Ph2CHK in THF at ꢀ78 ꢁC.
symmetrical shape with a narrow MWD (Mw/Mn ¼ 1.04).
The molecular weight (Mn ¼ 20,300) was in well accordance
with the calculated molecular weight (19,900). The results
shown in Table 1 and Figure 2(a) demonstrate that the ani-
onic polymerization of A with Ph2CHK proceeded quantita-
tively without the occurrence of any side reactions, indicat-
ing that the living poly(A) is stable at ꢀ78 ꢁC for 4 h
(Scheme 2).
Anionic Polymerization of B
Table 1 shows the results of anionic polymerizations of B.
First, the anionic polymerization of B was performed at ꢀ78
ꢁC for 4 h. After termination, a polymeric product with a low
yield was obtained, and most of the unreacted monomer was
1
recovered. H NMR and SEC measurements confirmed that a
polymeric product with a much higher molecular weight
than expected and a broad MWD had been produced
[Fig. 2(b) and Fig. S2 in the Supporting Information]. Next,
we performed the polymerization of B for a longer time
(24 h), but the well-defined poly(B) was not successfully
synthesized, as summarized in Table 1. The 1H NMR and
SEC analyses of the resulting polymeric product revealed
identical results to those of the polymerization performed
for 4 h.
This conclusion supports that the anionic polymerization of A
was successfully performed under the conditions used in our
previous study on the anionic polymerization of 2-(4-vinylphe-
nyl)pyridine.9 However, the polymerization times required for
100% yield of the polymers were 4 h for A and 2.5 h for 2-(4-
vinylphenyl)pyridine, respectively, suggesting that the polymer-
ization rate of A appeared to be slower than that of 2-(4-vinyl-
phenyl)pyridine under the same polymerization conditions.
Therefore, it is considered from this observation that the dif-
ferent behavior of these polymerizations is ascribed to ethynyl
group that may affect the reactivity of A.
To the best of our knowledge, we now suppose that these
results are attributed to side reactions based on the results
of our previous study on the anionic polymerization of 2-(4-
vinylphenyl)pyridine performed with K-Naph or sec-BuLi at
ꢀ78 ꢁC.9 In this article, it was demonstrated that a poly-
meric product having a broad MWD and a much higher Mn
value than predicted was obtained in a very low yield, and
2-(4-vinylphenyl)pyridine was quantitatively recovered after
the reaction. Accordingly, it is proposed from these findings
that the plausible side reactions, which include direct nucleo-
philic attack of Ph2CHK on the pyridine moiety during initia-
tion (Scheme 3, case 1) and nucleophilic attack of the propa-
gating carbanion on the pyridine moiety between polymer
chains during propagation (Scheme 3, case 2), occurred dur-
Additionally, poly(A) was prepared using various molar
ratios of A to Ph2CHK to confirm the living nature (Table 1,
run 4–7). As shown in Figure 3, the good linear relationship
between Mn value and the feed ratio of A to Ph2CHK indi-
cates a living nature of poly(A).
ꢁ
ing the course of the polymerization of B at ꢀ78 C.
In contrast, the polymerization of B proceeded quantitatively
at a higher temperature (0 ꢁC) for 2 h. The chemical struc-
ture of the resulting polymer and the occurrence of the ani-
onic polymerization were confirmed by 1H (Fig. S2 in the
Supporting Information) and 13C NMR and FTIR. Moreover,
the observed Mn values determined by SEC agreed well with
the calculated molecular weights, and the MWDs of the
resulting poly(B) were ꢄ1.20. However, a bimodal peak with
a small trace at the high Mn region was observed in the SEC
curve (Fig. 4). For 1 h polymerization time, the analyses of
the polymerization were identical to those of the polymeriza-
tion performed for 2 h, although the polymer yield was only
FIGURE 3 Plot of the feed ratio of A to Ph2CHK versus Mn and
Mw/Mn.
5204
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
SCHEME 3 Proposed anionic polymerization behavior of B with Ph2CHK in THF at ꢀ78 ꢁC.
72.0%. These results indicate that side reactions may take
place to some extent between polymer chains during poly-
clusion that polymerization behaviors of B at ꢀ78 and 0 ꢁC
are different (Fig. S3 in the Supporting Information).
10,39
ꢁ
merization of B at 0 C.
of polymerization solutions of B were deep violet at ꢀ78 C
The observation that the colors
ꢁ
Anionic Polymerization of C
ꢁ
We performed the anionic polymerization of C at ꢀ78 ꢁC
(Table 1, run 14–16). When C was added to the initiator so-
lution, the color of Ph2CHK immediately changed to deep
blue (Fig. S3 in the Supporting Information). This distinct
color derived from propagating carbanion of living poly(C)
was kept during the course of the polymerization. The yield
increased from 77.7% to 100% as the polymerization time
increased from 4 to 6 h. All the observed Mn values esti-
mated by SEC were in good agreement with calculated mo-
lecular weights. As shown in Figure 2(c), the SEC curve of
the resulting poly(C) was observed to be unimodal and sym-
metrical, although the MWD was somewhat broad (Mw/Mn ¼
1.31).
and deep red at 0 C, respectively, strongly supports the con-
It was reported that poly(4-vinylpyridine) above a certain
molecular weight is not soluble in THF, and this gives rise to
a heterogeneous polymerization medium, which results in
synthesis of polymer with somewhat broad MWD.40,41 How-
ever, in our study, poly(C) having more than Mn of 10,000
was soluble in THF. In addition, the reaction medium was
deep blue observed in the anionic polymerization of A under
the same conditions (Fig. S3 in the Supporting Information).
From these results, we hypothesized that the relatively broad
FIGURE 4 SEC curves of poly(B) synthesized with Ph2CHK in
THF at 0 ꢁC for 1 and 2 h.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5205

ARTICLE
WWW.POLYMERCHEMISTRY.ORG
TABLE 2 Block Copolymerization of A With 2-Vinylpyridine and Methyl Methacrylate Using Ph2CHK in THF at 278 8Ca
Block Copolymer (Homopolymer)
Monomer
2nd (mmol)
Mn ꢃ 10ꢀ3
Initiator
(mmol)
Yieldd
(%)
Calcdb
Obsdc
Mw/Mn
c
Run
1st (mmol)
1
2
3
4
a
0.0139
0.0144
0.0199
0.0197
A, 0.485
2VP,e 0.644
A, 0.218
MMA,g 0.483
13.6 (7.2)
–f (6.8)
–f (1.07)
100
100
100
0
2VP, 1.53
A, 0.739
15.3 (11.2)
10.2 (7.6)
17.4 (9.9)
14.0 (11.4)
1.10 (1.09)
10.8 (7.3)
1.13 (1.07)
h
h
MMA, 1.95
A, 0.617
–
(10.7)
–
(1.18)
d
e
f
Total polymerization times were 4.5 h, 4 h for A and 0.5 h for 2VP and
Yield of the second-stage polymerization.
2-Vinylpyridine.
The initiator efficiency was not quantitative, forming
MMA.
b
Mn(calcd) ¼ (molecular weight of monomer) ꢃ [monomer]/[initiator].
a
mixture of
c
Mn(obsd) and Mw/Mn were obtained by size exclusion chromatogra-
homopolymer and block copolymer.
g
phy calibration with polystyrene standards in THF solution containing
2% triethylamine as the eluent at 40 ꢁC.
Methyl metharylate.
h
No second-stage polymerization proceeded.
MWD might be caused by a slower rate of initiation as com-
pared to the rate of propagation.33 Thus, the polymerization
of C was attempted at elevated temperature (0 ꢁC) for 2 h.
The yield of the polymer was found to be 45.8%, and the
presence of a shoulder at the high Mn region of the SEC
curve was confirmed (Fig. S4 in the Supporting Information).
These indicate that side reactions probably take place inter-
molecularly between polymer chains during the polymeriza-
the pyridine moiety. Living anionic polymerization of A was
performed successfully, whereas side reactions took place
between the polymer chains during the course of the poly-
merizations of B, and the poly(C) with a relatively broad
MWD was obtained from the polymerization of C. It can be
suggested that these results are likely due to the resonance
effects and electron-withdrawing characters of isomeric pyri-
dine moieties, which may have significant effects on the reac-
tivities of A–C.33,39
40
ꢁ
tion of C at 0 C.
From the results of the anionic polymerizations of A–C, it
was apparent that their polymerization behaviors were quite
different depending on the position of the nitrogen atom on
Block Copolymerization of A with 2VP and MMA
From the synthetic point of view, well-defined block copoly-
mers containing ethynylpyridine moieties can be synthesized
FIGURE 5 SEC curves of (a) poly(A) at the first-stage polymerization and copolymerization product at the second-stage polymeriza-
tion with 2VP (Table 2, run 1): poly(A), Mn(obsd) ¼ 6800, Mw/Mn ¼ 1.07, (b) poly(2VP) at the first-stage polymerization and copoly-
merization product at the second-stage polymerization with A (Table 2, run 2): poly(2VP), Mn(obsd) ¼ 11,400, Mw/Mn ¼ 1.09;
poly(2VP)-b-poly(A), Mn(obsd) ¼ 14,000, Mw/Mn ¼ 1.10, (c) poly(A) at the first-stage polymerization and copolymerization product
at the second-stage polymerization with MMA (Table 2, run 3): poly(A), Mn(obsd) ¼ 7300, Mw/Mn ¼ 1.07; poly(A)-b-poly(methyl
methacrylate), Mn(obsd) ¼ 10,800, Mw/Mn ¼ 1.13, and (d) nucleophilicity order of living poly(A).
5206
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
SCHEME 4 Block copolymerization of 2VP with A with Ph2CHK in THF at ꢀ78 ꢁC.
via the successful living anionic polymerization of A. Further-
more, the relative reactivity of A and the terminal carbanion
of the resulting living polymer can be confirmed based on
the results of block copolymerization. Thus, 2VP and MMA
were chosen as comonomers for A.
curve of block copolymer was symmetrical and unimodal
and completely shifted to the higher Mn region after A was
added. These observations indicate that living poly(2VP) is
sufficiently nucleophilic to polymerize A under the condi-
tions used here.
The results of block copolymerization are summarized in Ta-
ble 2. First, the block copolymerization of A with 2VP was
attempted by the sequential addition of A as the first mono-
mer and 2VP as the second monomer. The polymer yield
was quantitative, but the SEC curve was bimodal [Fig. 5(a)].
While the peak at the low Mn region matched that of
poly(A), the peak at the high Mn region might correspond to
a block copolymer with an Mn value much higher than
expected. These results could be due to slow initiation with
rapid consumption of 2VP by the newly formed polystyryl
anion.6,10 This means that the living poly(A) cannot com-
pletely polymerize 2VP, suggesting low nucleophilicity of the
living poly(A) toward 2VP. In contrast, a well-defined block
copolymer, poly(2VP)-b-poly(A), with a predictable molecular
weight (Mn ¼ 14,000) and a narrow MWD (Mw/Mn ¼ 1.10)
was quantitatively obtained by the reverse addition of two
monomers (Scheme 4). As shown in Figure 5(b), the SEC
Next, the block copolymerization of A with MMA was per-
formed in the absence of any additives. As listed in Table 2,
the polymerization proceeded quantitatively, and poly(A)-b-
poly(MMA) had predictable molecular weight and narrow
MWD. Figure 5(c) shows that the SEC curve of the resulting
block copolymer was unimodal and symmetrical and shifted
from the starting poly(A) toward the higher molecular side.
Therefore, it is suggested that living poly(A) is stable at ꢀ78
ꢁC for 4 h and can certainly polymerize MMA without any
additives. Subsequently, the block copolymerization was per-
formed by the sequential addition of MMA as the first mono-
mer and A as the second monomer. However, 1H NMR and
SEC analyses of the resulting polymers confirmed that no po-
lymerization proceeded at the second-stage. No block copoly-
mer was obtained, and the second monomer, A, was quanti-
tatively recovered after termination. Accordingly, it can be
concluded from the results of block copolymerization that
the nucleophilicity of living poly(A) is between that of 2VP
and MMA, as shown in Figure 5(d).
TABLE 3 Solubilities of Poly(A–C) and Poly(2-vinylpyridine)
Polymer
Poly Poly Poly Poly
Solvent
(A)
(B)
(C)
(2-vinylpyridine)
n-Hexane
I
I
I
I
Cyclohexane
Diethyl ether
Ethyl acetate
Chloroform
Acetone
I
I
I
I
I
I
I
I
I
I
I
S
S
S
S
S
S
S
S
S
I
S
I
S
I
S
I
1,4-dioxane
Tetrahydrofuran
N,N-dimethylformamide
Dimethyl sulfoxide
Ethanol
S
S
S
S
I
S
S
S
S
I
S
S
S
S
I
Methanol
I
I
I
Water
I
I
I
FIGURE 6 TGA thermogram of poly(A–C) under nitrogen with a
S: soluble, I: insoluble.
heating rate of 10 ꢁC/min.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5207

ARTICLE
WWW.POLYMERCHEMISTRY.ORG
TABLE 4 Thermal Properties of Poly(A–C)
thank the Korea Basic Science Institute (KBSI) for assistance
with EA measurements.
a
b
Polymer
Mn(obsd)
T5 (ꢁC)
Tg (ꢁC)
Poly(A)
Poly(B)
Poly(C)
a
20,300
20,800
9800
494
478
475
166
160
174
REFERENCES AND NOTES
1 Szwarc, M. Nature 1956, 178, 1168–1169.
2 Fetters, L. J.; Firer, E. M.; Dafanti, M. Macromolecules 1977,
10, 1200–1207.
5% Weight loss temperature.
b
Determined by the second scan.
3 Zhang, H.; Ruckenstein, E. Macromolecules 1999, 32, 5495–
5500.
Solubilities and Thermal Properties
4 Senshu, K.; Kobayashi, M.; Ikawa, N.; Yamashita, S.; Hirao,
The solubilities of poly(A–C) were tested using common or-
ganic solvents at room temperature, as shown in Table 3.
These polymers were soluble in chloroform, 1,4-dioxane,
tetrahydrofuran, N,N-dimethylformamide, and dimethylsulf-
oxide, but were insoluble in n-hexane, cyclohexane, diethyl
ether, ethyl acetate, acetone, ethanol, methanol, and water.
Interestingly, they were insoluble in ethanol and methanol,
while poly(2VP) was soluble in both of these solvents. This
discrepancy is likely due to the lower polarity of the ethynyl-
pyridine moieties compared with the pyridine ring.42
A.; Nakahama, S. Langmuir 1999, 15, 1763–1769.
5 Hirao, A.; Kubota, S.; Sueyoshi, T.; Sugiyama, K. Macromol
Chem Phys 2001, 202, 1044–1052.
6 Ishizone, T.; Uehara, G.; Hirao, A.; Nakahama, S.; Tsuda, K.
Macromolecules 1998, 31, 3764–3774.
7 Hirao, A.; Nakahama, S. Prog Polym Sci 1990, 15, 299–335.
8 Hirao, A.; Loykulnant, S.; Ishizone, T. Prog Polym Sci 2002,
27, 1399–1471.
9 Kang, N. G.; Changez, M.; Lee, J. S. Macromolecules 2007,
40, 8553–8559.
10 Kang, B. G.; Kang, N. G.; Lee, J. S. Macromolecules 2010,
The thermal stabilities of poly(A–C) were determined by
TGA under nitrogen. The TGA thermograms and the values
of the 5% weight loss temperatures (T5s) of the polymers
are shown in Figure 6 and Table 4. They exhibited high T5
values, corresponding to good thermal stability. The glass
transition temperatures (Tgs) of the resulting poly(A–C)
measured by DSC was summarized in Table 4. They were
found to have Tg values comparable with that (163 ꢁC) of
poly(4-(phenylethynyl)styrene).6
43, 8400–8408.
11 Cho, Y. S.; Lee, J. S. Macromol Rapid Commun 2001, 22,
638–642.
12 Cho, Y. S.; Ihn, C. S.; Lee, H. K.; Lee, J. S. Macromol Rapid
Commun 2001, 22, 1249–1253.
13 Cho, Y. S.; Ihn, C. S.; Kim, S. W.; Lee, J. S. Polymer 2001,
42, 7611–7616.
14 Cho, Y. S.; Lee, H. K.; Lee, J. S. Macromol Chem Phys 2002,
203, 2495–2500.
15 Cho, Y. S.; Lee, J. S.; Cho, G. Polymer 2002, 43, 1197–1202.
16 Thelakkat, M. Macromol Mater Eng 2002, 287, 442–461.
CONCLUSIONS
17 Deng, L.; Furuta, P. T.; Garon, S.; Li, J.; Kavulak, D.; Thomp-
son, M. E.; Fre´chet, J. M. J. Chem Mater 2006, 18, 386–395.
The anionic polymerization results of three ethynylstyrene
derivatives containing isomeric pyridine moieties, 2-(2-(4-
vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl)ethy-
nyl)pyridine (B), and 4-(2-(4-vinylphenyl)ethynyl)pyridine
(C), illustrate that the polymerization behaviors of these
monomers were strongly influenced by the position of the
nitrogen atom on the pyridine moiety under the polymeriza-
tion conditions used in this study. The poly(A) possessed
predictable molecular weights and narrow MWDs. In con-
trast, living anionic polymerization of B and C was not per-
formed successfully. In the polymerization of B, side reac-
tions occurred between the polymer chains during the
polymerization at both ꢀ78 and 0 ꢁC, and the resulting
poly(C) synthesized at ꢀ78 ꢁC possessed somewhat broad
MWDs because of slow initiation. It is believed that the dif-
ferent outcomes of these polymerization reactions are due to
the resonance effects and electron-withdrawing characters of
the isomeric pyridine moieties, which may have significant
effects on the reactivities of A–C. Moreover, it was found that
the nucleophilicity of living poly(A) is between that of 2VP
and MMA. Further studies on the functionalities of ethynyl-
pyridine moieties will be undertaken in the near future.
18 Shirota, Y.; Kageyama, H. Chem Rev 2007, 107, 953–1010.
19 Park, M. H.; Huh, J. O.; Do, Y.; Lee, M. H. J Polym Sci Part
A: Polym Chem 2008, 46, 5816–5825.
20 Park, J. H.; Yun, C.; Park, M. H.; Do, Y.; Yoo, S.; Lee, M. H.
Macromolecules 2009, 42, 6840–6843.
21 Palai, A. K.; Mishra, S. P.; Kumar. A.; Srivastava, R.; Kamala-
sanan, M. N.; Patri, M. J Polym Sci Part A: Polym Chem 2011,
49, 832–841.
22 Lessard, B.; Ling, E. J. Y.; Morin, M. S. T.; Maric, M. J Polym
Sci Part A: Polym Chem 2011, 49, 1033–1045.
23 Shin, Y. D.; Han, S. H.; Samal, S.; Lee, J. S. J Polym Sci Part
A: Polym Chem 2005, 43, 607–615.
24 Kang, N. G.; Kang, B. G; Koh, H. D.; Changez, M.; Lee, J. S.
React Funct Polym 2009, 69, 470–479.
25 Changez, M.; Kang, N. G.; Lee, C. H.; Lee, J. S. Small 2010,
6, 63–68.
26 Changez, M.; Kang, N. G.; Koh, H. D.; Lee, J. S. Langmuir
2010, 26, 9981–9985.
27 Tsuda, K.; Hirahata, W.; Yokota, K.; Kakuchi, T.; Ishizone, T.;
Hirao, A. Polym Bull 1997, 39, 173–178.
28 Tsuda, K.; Tsutsumi, K.; Yaegashi, M.; Miyajima, M.; Ishi-
zone, T.; Hirao, A.; Ishii, F.; Kakuchi, T. Polym Bull 1998, 40,
651–658.
This work was supported by the Program for Integrated Molec-
ular System (PIMS) and the World Class University (WCU) Pro-
gram (Project No. R31-20008-000-10026-0). The authors
29 Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew Chem Int
Ed Engl 2001, 40, 2004–2021.
5208
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209

WWW.POLYMERCHEMISTRY.ORG
ARTICLE
30 Binder, W. H.; Sachsenhofer, R. Macromol Rapid Commun
37 Ishizone, T.; Sueyasu, N.; Sugiyama, K.; Hirao, A.; Naka-
2007, 28, 15–54.
hama, S. Macromolecules 1993, 26, 6976–6984.
31 Sumerlin, B. S.; Vogt, A. P. Macromolecules 2010, 43, 1–13.
38 Ishizone, T.; Hirao, A.; Nakahama, S. Macromolecules 1991,
24, 625–626.
32 Ishizone, T.; Hirao, A.; Nakahama, S.; Kakuchi, K.; Yokota,
K.; Tsuda, K. Macromolecules 1991, 24, 5230–5231.
39 Ishizone, T.; Sugiyama, K.; Hirao, A.; Nakahama S. Macro-
molecules 1993, 26, 3009–3018.
33 Tsuda, K.; Ishizone, T.; Hirao, A.; Nakahama, S.; Kakuchi, K.;
Yokota, K. Macromolecules 1993, 26, 6985–6991.
40 Varshney, S. K.; Zhong, X. F.; Eisenberg, A. Macromolecules
1993, 26, 701–706.
34 Sugiyama, K.; Ishizone, T.; Hirao, A.; Nakahama, S. Acta
Polym 1995, 46, 424–431.
41 Creutz, S.; Teyssie´, P.; Je´roˆ me, R. Macromolecules 1997, 30,
1–5.
35 Ishizone, T.; Kato, R.; Ishino, Y.; Hirao, A.; Nakahama, S.
Macromolecules 1991, 24, 1449–1454.
42 Ishizone, T.; Oka, N.; Hirao, A.; Nakahama, S. Macromole-
36 Hirao, A.; Nakahama, S. Macromolecules 1987, 20, 2968–2972.
cules 1996, 29, 528–534.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 5199–5209
5209