Photon Factory Activity Report 2005 #23 Part B (2006)
Materials Science

10C/2004G093

SR-SAXS studies on morphology formation in a binary blend of crystallineamorphous diblock copolymer and crystalline homopolymer. 1.
Michiaki AKABA, Takayuki OHSUGI, and Shuichi NOJIMA*
Department of Organic and Polymeric Materials, Graduate School of Science and Engineering,Tokyo Institute of Technology, H-125, 2-12-1 Ookayama, Meguro-ku Tokyo 152-8552, Japan

Results and Discussion
Fig. 1 shows the typical time-resolved SR-SAXS
curves for the blend (80 wt.%PCL) quenched from 120 oC
into 40 oC. Immediately after quenching, we can observe
the SAXS peak (A), which arises from the microdomain
structure existing at 120 oC. This peak decreases inintensity with crystallization time tc, and simultaneously
two peaks at higher (C) and lower (B) angles appear,
Table Molecular characteristics of the samples used in this study
SampleTotal Mna)

PCL-b-PB 13,000
PCL

3,500

Mw/Mnb)

PCL:PBc)

Ethyl Branchc)

Tmd)(vol.%)(mol%)

(oC)

1.16

66:34

754

1.50--58a) Determined by membraneosmometry. b) Determined by GPC.
c) Determined by 1H-NMR. d) Determined by DSC.

References[1] S. Nojima et al., Macromolecules, 25, 1922 (1992).
[2] M. Akaba and S. Nojima, Polym. J., 37, 464 (2005).
* snojima@polymer.titech.ac.jp
DBC
900 sec

Intensity (a.u.)

Experimental Section
Samples We used poly(ε-caprolactone)-block-polybutadiene (PCL-b-PB) as a crystalline block copolymerand poly(ε-caprolactone) (PCL) as a crystalline homopolymer (Table). The blend was prepared by a solventcasting method using benzene as a common solvent.
SR-SAXS measurements The SR-SAXS experiment wasperformed at beam line BL-10C. The accumulation timewas 10 sec for each measurement. The backgroundscattering and Lorentz factor were taken into account, andfinally the relative intensity was obtained as a function ofwave number s (= (2/λ)sin θ, 2θ: scattering angle).

which come from the crystallized PCL and PCL-b-PB
regions, respectively. In addition, we can observe a
monotonically increasing scattering toward s -> 0 (D),which arises from the mosaic structure consisting of thecrystallized two regions.
The tc dependence of normalized intensity, the peakintensity divided by the final intensity, is plotted in Fig. 2for each SAXS peak. It is found that the crystallization in
the PCL and PCL-b-PB regions proceeds in a same
fashion because the normalized peak intensities make one
master curve, though the crystallization rate of neat PCL
is sufficiently faster than that of neat PCL-b-PB.

A
0.00

0.05

0.10

0.15

0.20

0 sec
0.25

0.30s (nm-1)

Fig. 1 Time-resolved SR-SAXS curves during crystallization
for the blend with φPCL = 0.8 after quenching from themicrophase-separated melt into Tc = 40 oC.
1.0

Normalized intensity

Introduction
We have previously investigated the morphology
formation in a binary blend consisting of amorphous andcrystalline homopolymers at various temperatures andcompositions by using time-resolved small-angle X-ray
scattering with synchrotron radiation (SR-SAXS)1, where
the morphology formation is driven by a combined effectof crystallization and phase separation. We found that twophases, i.e., crystalline phase and amorphous phase,appeared in the system and the ratio of these phases did
not change during the morphology formation. However,
we did not get information from the amorphous phasebecause it provided no SAXS signal.
In this study2, we use a crystalline-amorphous diblock
copolymer instead of amorphous homopolymer. The
crystalline-amorphous
diblock
copolymer
yieldscharacteristic structures before and after crystallizationand therefore we can get information from this region on
the process of morphology formation.

0.8
0.6
0.4
0.20.00200

4006008001000

Time (sec)Fig. 2 Normalized intensities for the microdomain structure ( ),crystallized PCL-b-PB region ( ), and crystallized PCL region ( )oplotted against tc for the blend with φPCL = 0.8 crystallized at 40 C.

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