The molecular mechanism of the strain–stress behavior of the ABA triblock copolymer is studied by combining self-consistent field (SCF) calculation and molecular dynamics (MD) simulation. First, the equilibrium structure was obtained by the SCF calculation. The bridge fraction φbridge was found to be about 0.4, 0.6, and 0.8 for lamellar, cylindrical, and spherical phases, respectively. From the segment distribution calculated by the SCF, the equilibrium chain configuration was generated by the method reported previously [Aoyagi et al., Comput. Phys. Comm. 145, 267 (2002)]. The loading and unloading behavior was then studied by the MD simulation. The loading curve shows a strain-softening, and then a yielding at a strain of about 350%, where the breakup of microdomains takes place. The strain–stress curve in the second elongation-compression cycle is different from that of the first cycle. Such hysteresis effect is seen also for small elongation where the domain breakup does not take place.

1.
Thermoplastic Elastomers, edited by G. Holden, N. R. Legge, and R. P. Quirk (Hanser Gardner, New York, 1996).
2.
E.
Prasman
and
E. L.
Thomas
,
J. Polym. Sci., Part B: Polym. Phys.
36
,
1625
(
1998
).
3.
R. W.
Richards
and
G.
Welsh
,
Eur. Polym. J.
31
,
1197
(
1995
).
4.
T.
Aoyagi
,
F.
Sawa
,
T.
Shoji
,
H.
Fukunaga
,
J.
Takimoto
, and
M.
Doi
,
Comput. Phys. Commun.
145
,
267
(
2002
).
5.
A. F.
Terzis
,
D. N.
Theodorou
, and
A.
Stroeks
,
Macromolecules
33
,
1397
(
2000
).
6.
A. F.
Terzis
,
D. N.
Theodorou
, and
A.
Stroeks
,
Macromolecules
35
,
508
(
2002
).
7.
M. W.
Matsen
and
M.
Schick
,
Macromolecules
27
,
187
(
1994
).
8.
H.
Watanabe
,
Macromolecules
28
,
5006
(
1985
).
9.
K.
Karatasos
,
S. H.
Anastasiadis
,
T.
Pakula
, and
H.
Watanabe
,
Macromolecules
33
,
523
(
2000
).
10.
J.
Huh
,
W. H.
Jo
, and
G.
ten Brike
,
Macromolecules
35
,
2413
(
2002
).
11.
H.
Watanabe
,
T.
Sato
,
K.
Osaki
,
M.-L.
Yao
, and
A.
Yamagishi
,
Macromolecules
30
,
5877
(
1997
).
12.
COGNAC (COarse Grained molecular dynamics program by NAgoya Cooperation) is a general-purpose coarse-grained molecular dynamics program which has been developed in our group. See COGNAC user’s manual for the details.
13.
SUSHI (Simulation Utilities for Soft and Hard Interfaces) is a dynamic mean field program which has been developed in our group. See SUSHI user’s manual for the details.
14.
OCTA is a hierarchical modeling system consisting of various simulation programs such as COGNAC and SUSHI, and graphical user interface for those programs, OCTA is open to the public. See web page, http://octa.jp for the details.
15.
E.
Helfand
and
Z. R.
Wasserman
,
Macromolecules
9
,
879
(
1976
).
16.
K. M.
Hong
and
J.
Noolandi
,
Macromolecules
14
,
727
(
1981
).
17.
G. J. Fleer, M. A. C. Stuart, J. M. H. M. Scheutjens, T. Cosgrove, and B. Vincent, Polymers at Interfaces (Chapman and Hall, London, 1993).
18.
K.
Kremer
and
G. S.
Grest
,
J. Chem. Phys.
92
,
5057
(
1990
).
19.
G. S.
Grest
,
M.-D.
Lacasse
,
K.
Kremer
, and
A. M.
Gupta
,
J. Chem. Phys.
105
,
10583
(
1996
).
20.
M.
Murat
,
G. S.
Grest
, and
K.
Kremer
,
Macromolecules
32
,
595
(
1999
).
21.
P. J. Flory, Principles of Polymer Chemistry (Cornell University Press, Ithaca, 1971).
22.
J.
Baschnagel
,
C.
Bennemann
,
W.
Paul
, and
K.
Binder
,
J. Phys.: Condens. Matter
12
,
6365
(
2000
).
23.
T. Aoyagi, J. Takimoto, and M. Doi, in Proceedings of the International Conference on Advanced Polymers and Processing (ICAPP2001) (in press).
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