C O M M U N I C A T I O N S
Table 1. Synthesis of ABC, ABCD, and ABCDE Asymmetric Star Polymers by Anionic Polymerization
samplea
M
(calcd)
M
(SEC)b
M
b
M
(NMR)c
M
(SLS)d
dn/dc (mL
‚
g-1)d
C (calcd)e
C (NMR)f
n
n
w
/M
n
n
w
S1
S2
S3
S4
S5
S6
S7
S8
31200
29800
31200
30600
41900
42000
42600
50000
20500
21900
23000
23300
31000
29300
33500
38600
1.02
1.03
1.02
1.02
1.02
1.03
1.02
1.03
31500
30100
32000
31200
43300
43200
43900
50400
32700
31800
34600
33500
44600
43600
44900
53600
0.174
0.173
0.167
0.173
0.180
0.178
0.175
0.165
31/31/38
32/33/35
31/35/34
31/34/35
24/24/25/27
24/24/26/26
23/23/24/30
19/20/23/21/17
31/31/38
32/34/34
30/35/35
31/34/35
23/23/25/29
23/23/25/29
23/23/24/30
19/20/23/20/18
a
S1-S4: ABC stars, where A and C were PS and PMePVSO segment, and B was PRMS (S1), PTMSS (S2), PMOS (S3), and PMeSt (S4). S5-S7:
ABCD stars, where A, B, and D were PS, PRMS, and PMePVSO segment, and C was PMOS (S5), PTMSS (S6), and PMeSt (S7). S8: ABCDE, where A,
b
c
1
B, C, D, and E segments were PS, PRMS, PTMSS, PMOS, and PMePVSO, respectively. Estimated by SEC in THF at 40 °C. Determined by H NMR.
d
Determined by SLS in THF at 25 °C. e Theoretically calculated weight composition. Weight composition determined by H NMR.
f
1
star polymers. This material is available free of charge via the Internet
at http://pubs.acs.org.
References
(
1) (a) Widawski, G.; Raviso, M.; Fran c¸ ois, B. Nature 1994, 369, 387. (b)
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Spatz, J. P.; M o¨ ller, M.; Meijer, E. W. J. Am. Chem. Soc. 1998, 120,
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798. (e) Wu, C.; Niu, A.; Leung, L. M.; Lam, T. S. J. Am. Chem. Soc.
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999, 121, 1954. (f) Malenfant, P. R. L.; Groenendaal, L.; Fr e´ chet, J. M.
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916. (h) Ikkala, O.; ten Brinke, G. Science 2002, 295, 2407. (i) Lecl e` re,
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M u¨ llen, K.; Br e´ das, J.-L.; Lazzaroni, R. Prog. Polym. Sci. 2003, 28, 55.
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2
005, 105, 1491 and references therein.
(
2) (a) Pispas, S.; Poulos, Y.; Hadjichristidis, N. Macromolecules 1998, 31,
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177. (b) Sioula, S.; Hadjichristidis, N.; Thomas, E. L. Macromolecules
1
998, 31, 5272 and 8429. (c) Pispas, S.; Hadjichristidis, N.; Potemkin, I.;
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3) (a) Quirk, R. P.; Yoo, T.; Lee, Y.; Kim, J.; Lee, B. AdV. Polym. Sci.
Figure 1. TGA curves of PMePVSO (a), S1 (b), and S1T (c).
(
2000, 153, 67. (b) Hadjichristidis, N.; Pispas, S.; Pitsikalis, M.; Iatrou,
expected. Meanwhile, sulfur is absolutely absent from the resultant
PS-PRMS-PA star polymer as determined by elemental analy-
sis. The above results confirmed the quantitative elimination of
H.; Vlahos, C. AdV. Polym. Sci. 1999, 142, 72. (c) Hadjichristidis, N.;
Pitsikalis, M.; Pispas, S.; Iatrou, H. Chem. ReV. 2001, 101, 3747. (d) Hirao,
A.; Hayashi, M.; Loykulnant, S.; Sugiyama, K.; Ryu, S. W.; Haraguchi,
N.; Matsuo, A.; Higashihara, T. Prog. Polym. Sci. 2005, 30, 111.
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Hashimoto, T. Polymer 1992, 33, 2208. (b) Iatrou, H.; Hadjichristidis, N.
Macromolecules 1992, 25, 4649. (c) H u¨ ckst a¨ dt, H.; Abetz, V.; Stadler,
R. Macromol. Rapid Commun. 1996, 17, 599. (d) Sioula, S.; Tselikas,
Y.; Hadjichristidis, N. Macromolecules 1997, 30, 1518. (e) Bellas, V.;
Iatrou, H.; Hadjichristidis, N. Macromolecules 2000, 33, 6993. (f) Li, Z.;
Hillmyer, M. A.; Lodge, T. P. Macromolecules 2004, 37, 8933.
4
-methylphenylsulfenic acid from S1. The resulting star polymer
(
containing a PA segment was soluble in DMF and partly soluble
in THF and chloroform. The PMePVSO segments in other star
samples were also readily and completely converted into the
corresponding PA segments.
In summary, a series of novel well-defined asymmetric ABC,
ABCD, and ABCDE star polymers containing conductive PA
segment and its soluble precursors have been successfully synthe-
sized by the iterative methodology followed by living anionic
polymerization of MePVSO. Their solution properties and mi-
crophase-separated structures are under investigation and will be
reported in a future publication.
(5) (a) Iatrou, H.; Hadjichristidis, N. Macromolecules 1993, 26, 2479. (b)
Higashihara, T.; Hirao, A. J. Polym. Sci., Part A: Polym. Chem. 2004,
4
2, 4535. (c) Higashihara, T.; Nagura, M.; Inoue, K.; Haraguchi, N.; Hirao,
A. Macromolecules 2005, 38, 4577.
(
6) (a) Hirao, A.; Hayashi, M.; Higashihara, T. Macromol. Chem. Phys. 2001,
202, 3165. (b) Hirao, A.; Higashihara, T. Macromolecules 2002, 35, 7238.
(7) Hogen-Esch and co-workers previously reported that the anionic polym-
erization of phenyl vinyl sulfoxide (PVSO) proceeded in a living manner,
and the resulting polymer, PPVSO, was completely converted to PA only
by thermal treatment (Kanga, R. S.; Hogen-Esch, T. E.; Randrianali-
manana, E.; Soum, A.; Fontanille, M. Macromolecules 1990, 23, 4235
and 4241). In this study, the more stable polymer derived from MePVSO
was used in place of PVSO. Similar to the polymerization of PVSO, the
anionic polymerization of MePVSO always gave the polymers with
Acknowledgment. The financial support of a Grant-in-Aid for
Scientific Research (No. 00164351) from the Ministry of Education,
Science, Sports, and Culture of Japan is gratefully acknowledged
by the authors. Y.Z. gratefully thanks the Japan Society for the
Promotion of Science Research Fellowships for Postdoctoral
Fellowship for Foreign Researchers for support.
relatively broad molecular weight distributions (M
w n
/M ) 1.3-1.5) in
THF at -78 °C. We have, however, found that the polymerization of
MePVSO could be significantly improved by adding a 10-fold excess or
more of LiCl or LiBr to afford the polymers with predictable M
n
values
and narrow molecular weight distributions (M /M ) 1.07-1.16).
w n
(8) (a) Chien, J.; Uden, P.; Fan, J. J. Polym. Sci., Polym. Chem. Ed. 1982,
2
0, 2159. (b) Will, F.; McKee, D. J. Polym. Sci., Polym. Chem. Ed. 1983,
1, 3479.
2
Supporting Information Available: Experimental details for the
synthesis and characterization of the monomer, homopolymers, and
JA054821L
J. AM. CHEM. SOC.
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VOL. 127, NO. 41, 2005 14159