Synthesis of a 1,2-Dithienylethene-Containing Donor-Acceptor Polymer via Palladium-Catalyzed Direct Arylation Polymerization (DArP)

Article abstract of DOI:10.3390/molecules23040981

This paper reports the synthesis of D-A polymers containing 1,2-dithienylethene (DTE) units via palladium-catalyzed direct arylation polymerization (DArP). The reaction of dibromoisoindigo (1-Br) and DTE (2-H), in the presence of Pd₂(dba)₃·CHCl₃ (0.5 mol%), P(2-MeOC₆H₄)₃ (L1) (2 mol%), pivalic acid (1 equiv) as catalyst precursors, and Cs₂CO₃ (3 equiv) as a base affords poly(1-alt-2) with a high molecular weight (M_n up to 44,900). Although, it has been known that monomers, with plural C–H bonds, tend to form insoluble materials via direct arylation at undesirable C–H positions; the reaction of 1-Br and 2-H cleanly proceeds without insolubilization. The resulting polymer has a well-controlled structure and exhibits good charge transfer characteristics in an organic field-effect transistor (OFET), compared to the polymer produced by Migita–Kosugi–Stille cross-coupling polymerization. The DArP product displays an ideal linear relationship in the current–voltage curve, whereas the Migita–Kosugi–Stille product shows a V_G-dependent change in the charge mobility.

Full text of DOI:10.3390/molecules23040981

molecules
Article
Synthesis of a 1,2-Dithienylethene-Containing
Donor-Acceptor Polymer via Palladium-Catalyzed
Direct Arylation Polymerization (DArP)
Masayuki Wakioka 1, ID , Natsumi Yamashita 1, Hiroki Mori 2, Yasushi Nishihara 2 and
*
Fumiyuki Ozawa 1,
*
ID
1
International Research Center for Elements Science (IRCELS), Institute for Chemical Research,
Kyoto University, Uji, Kyoto 611-0011, Japan; yamashita.natsumi.22v@st.kyoto-u.ac.jp
Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushimanaka, Kita-ku,
Okayama 700-8530, Japan; h-mor@okayama-u.ac.jp (H.M.); ynishiha@okayama-u.ac.jp (Y.N.)
Correspondence: wakioka@scl.kyoto-u.ac.jp (M.W.); ozawa@scl.kyoto-u.ac.jp (F.O.)
2
*
ꢀꢁꢂꢀꢃꢄꢅꢆꢇ
ꢀꢁꢂꢃꢄꢅꢆ
Received: 10 April 2018; Accepted: 20 April 2018; Published: 23 April 2018
Abstract: This paper reports the synthesis of D-A polymers containing 1,2-dithienylethene (DTE) units
via palladium-catalyzed direct arylation polymerization (DArP). The reaction of dibromoisoindigo
(
1
-
Br) and DTE (
2
-
H
), in the presence of Pd2(dba)3
·
CHCl3 (0.5 mol%), P(2-MeOC6H4)3 (L1) (2 mol%),
-alt-
pivalic acid (1 equiv) as catalyst precursors, and Cs2CO3 (3 equiv) as a base affords poly(
1
2)
with a high molecular weight (Mn up to 44,900). Although, it has been known that monomers,
with plural C–H bonds, tend to form insoluble materials via direct arylation at undesirable C–H
positions; the reaction of 1-Br and 2-H cleanly proceeds without insolubilization. The resulting
polymer has a well-controlled structure and exhibits good charge transfer characteristics in an
organic field-effect transistor (OFET), compared to the polymer produced by Migita–Kosugi–Stille
cross-coupling polymerization. The DArP product displays an ideal linear relationship in the
current–voltage curve, whereas the Migita–Kosugi–Stille product shows a VG-dependent change in
the charge mobility.
Keywords: direct arylation; polycondensation; palladium catalyst; conjugated polymer
1. Introduction
π
-Conjugated polymers with donor–acceptor combinations of repeated units (D-A polymers)
often exhibit a high device performance in organic field-effect transistors (OFETs) and thin-film solar
cells [ ]. Thus far, such polymers have been prepared by Migita–Kosugi–Stille cross-coupling
polymerization. However, this method needs toxic tin reagents for the monomer preparation, and the
polymerization forms a highly toxic side product such as Me3SnBr [ ]. It has also been implicated
that the residual impurities that arise from tin reagents may deteriorate the device performance [ ].
In this context, the palladium-catalyzed direct arylation polymerization (DArP), that proceeds via C–H
bond activation, has recently emerged as a simple yet fundamental solution for these problems [10 12].
We have developed a highly efficient DArP catalyst using P(2-MeOC6H4)3 (L1) as a ligand to produce
D-A polymers with a high molecular weight [13 20]. The resulting polymers have well-controlled
1–4
5
6–9
–
–
structures without tin impurities, thereby leading to good material properties [16].
In this study, we examined the synthesis of a D-A polymer with 1,2-dithienylethene (DTE) as donor
units; poly(
by Migita–Kosugi–Stille cross-coupling polymerization and have proven to be competent compounds
in OFETs [21 23]; however, their synthesis via DArP has been poorly successful [24]. This is probably
1-alt-2) in Scheme 1. DTE-based D-A polymers, such as poly(1-alt-2), have been prepared
–
Molecules 2018, 23, 981; doi:10.3390/molecules23040981
www.mdpi.com/journal/molecules

Molecules 2018, 23, 981
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due to the existence of plural C–H bonds in DTE. Direct arylation at undesirable C–H positions forms
branching and cross-linking polymers, which eventually change to insoluble materials [25 28]. On the
other hand, we found that the L1-based catalyst successfully produces the desired poly( -alt- ) without
–
1
2
formation of insoluble materials. The resulting polymer has a well-controlled structure and shows
better charge transfer properties in OFET than Migita–Kosugi–Stille cross-coupling products.
Scheme 1. Synthesis of poly(1-alt-2) via DArP.
2. Results and Discussion
2.1. Synthesis of Poly(1-alt-2)
First, we examined the DArP of dibromoisoindigo (1-Br) and DTE (2-H) in several types
of solvents (Scheme 1). Table 1 summarizes the results. The reaction was conducted with
Pd2(dba)3
·
CHCl3 (0.5 mol%), L1 (2 mol%), pivalic acid (1 equiv) as catalyst◦precursors, and Cs2CO3
(3 equiv) as a base. When the reaction was carried out in toluene at 100 C, the reaction mixture
turned into a dark red mass in 5 h; however, Soxhlet extraction with o-Cl2C6H4 afforded poly(1-alt-2)
(Mn = 17,000) in almost quantitative yield and no colored substance remained in the extraction thimble
(run 1). THF was less effective as a solvent, giving a low-molecular weight polymer (Mn = 7400) (run 2).
On the other hand, the molecular weight increased in 2-MeTHF (Mn = 22,700) (run 3), and when
a low-molecular weight portion was removed by Soxhlet extraction with CHCl3, poly(1-alt-2) with
Mn = 44,900 was obtained in a recovery rate of 63% (run 3a). Unlike the reaction in toluene, the reaction
system retained liquidity in 2-MeTHF.
Table 1. DArP of 1-Br and 2-H.
3
3
Run 1
Solvent
Time (h)
Yield (%) 2
Mn
Mw/Mn
1
2
3
3a
4 5
5 5
toluene
THF
2-MeTHF
5
99
80
>99
(63) 4
93
17,000
7,400
22,700
(44,900) 4
15,700
14,100
2.6
2.0
48
24
-
24
96
3.9
(2.2) 4
2.3
-
toluene
2-MeTHF
>99
2.5
1
Reactions were run at 100 ◦C using 1-Br (0.20 mmol) and 2-H (0.20 mmol), Pd2(dba)3
CHCl3 (0.5 mol%),
·
L1 (2 mol%), Cs2CO3 (0.60 mmol), and pivalic acid (0.20 mmol) in toluene (0.40 mL) unless otherwise stated.
2
3
Isolated yield after Soxhlet extraction with hexane, acetone, and o-Cl2C6H4. Determined by GPC calibration
based on polystyrene standards (140 ◦C, o-Cl2C6H4). After removal of a low molecular weight portion from
the product in run 3 by Soxhlet extraction with CHCl3. The reaction was carried out in the presence of TMEDA
4
5
(10 mol%).
Next, we examined the synthesis of poly(
tetramethylethylenediamine (TMEDA). We have documented that, while the reaction becomes slow,
1-alt-2)
in the presence of N,N,N0,N0-

Molecules 2018, 23, 981
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the combined use of L1 and TMEDA effectively prevents the formation of structural defects, including
homocoupling, branching, and cross-linking defects leading to insolubilization [18 19]. The reaction
in toluene proceeded without the formation of a solid mass, and poly( -alt- ) with Mn = 15,700 was
,
1
2
produced in a high yield, in 24 h (run 4). On the other hand, the DArP in the presence of TMEDA was
significantly slow in 2-MeTHF, and the molecular weight remained moderate, even after 96 h (run 5).
For comparison, poly(
polymerization (Scheme 2). Referring to the literature [22
1
-alt-
2
)
was prepared by Migita–Kosugi–Stille cross-coupling
23], the reactions of Br and SnMe3 were
,
1-
2-
examined in toluene under two catalytic conditions. The reaction in the presence of Pd2(dba)3
·
CHCl3
◦
(2 mol%) and P(o-tolyl)3 (8 mol%) at 90 C for 24 h yielded poly(
1
-alt-
2) with moderate molecular
weight (Mn = 17,700, PDI = 1.7) in quantitative yield [22]. Although the GPC molecular weight of the
polymer prepared under those reactions conditions has been reported to be Mn = 98,800 (PDI = 3.1),
◦
this value has been estimated at 40 C, using CHCl3 as the column eluate [22]. In contrast, we
performed GPC calibration at 140 ◦C, using o-Cl2C6H4. Thus, we re-examined the polymer under
the same GPC conditions using CHCl3 and confirmed that our product (Mn = 93,400, PDI = 4.6) has
comparable molecular weight to that of the literature.
Scheme 2. Synthesis of poly(1-alt-2) via Migita–Kosugi–Stille cross-coupling polymerization.
The synthesis of poly(
1
-alt-
2
) via Migita–Kosugi–Stille cross-coupling was also carried out◦under
dilute conditions (monomers: 8 mM) using a large amount of P(o-tolyl)3 (16 mol%) at 115 C for
48 h [23]. In this case, the resulting polymer was sparingly soluble and unable to be examined by
GPC using o-Cl2C6H4 at 140 ◦C, whereas the molecular weight could be estimated at 150 ◦C using
1,2,4-Cl3C6H3 as the column eluate (Mn = 53,800, PDI = 2.8). The NMR analysis described below was
performed for a soluble part of the product, prepared by Soxhlet extraction with CHCl3 (18% recovery,
Mn = 24,400, PDI = 2.5).
1
2.2. H-NMR Analysis of Poly(1-alt-2)
Figure 1 compares 1H-NMR spectra of the four types of poly(
1-alt-2)s prepared by DArP (a and b)
and Migita–Kosugi–Stille cross-coupling polymerization (c and d). The signal assignments are based
on the spectra of model compounds of substructures and structural defects (see the Supplementary
Material). In Figure 1a—for the polymer of run 4, Table 1 (Mn = 15,700)—the spectrum consists of the
main signals due to cross-coupling units (A1
groups (a1 a3 b1 b4, and c1 c7). Although the signal due to
its ratio is less than 0.1%. On the other hand, signals assignable to
–
A6) and small signals arise from three kinds of terminal
homocoupling defects ( ) is observed,
homocoupling, branching, and
–
,
–
–
1-
1
B
2-2
cross-linking defects are not observed. Figure 1b, which corresponds to the polymer of run 3 in Table 1
(Mn = 22,700), displays the same signals as Figure 1a, although the relative intensity of each unit is
changed, and the signals are broadened reflecting the increase in molecular weight. The number of 1-1

Molecules 2018, 23, 981
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homocoupling defects (B) is estimated to be less than 0.1%, whereas other structural defects are not
observed. Hence, the highly controlled structures of the DArP polymers have been confirmed.
Figure 1. 1H-NMR spectra of poly(
1-alt-2) prepared via DArP (Mn = 15,700 (
a) and Mn = 22,700 (
b)) and
Migita–Kosugi–Stille cross-coupling polymerization (Mn = 17,700 (
at 130 C (600 MHz). *: unidentified signals.
c
) and Mn = 24,400 ( )) in C2D2Cl4
d
◦
On the other hand, Figure 1c,d for the Migita–Kosugi–Stille cross-coupling products (Mn = 17,700
and 24,400) contain many unidentified peaks in addition to the signals assigned to the core and
terminal groups of poly(1-alt-2). Moreover, the signals are somewhat broadened as compared to the
DArP products of comparable molecular weight.
2.3. Electronic Properties of Poly(1-alt-2)
Table 2 summarizes the optical and electrochemical properties of poly(1-alt-2)s, in thin film,
which were evaluated by UV–vis spectroscopy and cyclic voltammetry. The absorption spectra of
poly( -alt- )s, listed in Table 2, are shown in Figure 2. All spectra consist of two absorption bands
1
2
around 600–700 (band I) and 650–750 nm (band II). The band I arises from the intramolecular charge
transfer (ICT) transitions in the donor–acceptor units, whereas the band II is induced for the aggregation

Molecules 2018, 23, 981
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of polymer chains through strong intermolecular interactions [29]. In Figure 2, the changes in the
relative intensity, from band II to band I, are small. The maximum absorption wavelengths of polymers
are approximately the same (
λ
max
= 638(3) and 700(2) nm). Moreover, the absorption onsets (
λ
)
onset
are within the range of 746–753 nm, showing that the optical band gaps are little affected by the
polymerization methods, as well as the molecular weight (Egopt = 1.66(1) eV). Indeed, the electronic
properties evaluated by cyclic voltammetry are consistent for all polymers: EHOMO
ELUMO = −3.60(3) eV, Eg = 1.74(2) eV.
=
−
5.34(2) eV,
CV
1.5
entry 1
entry 2
entry 3
entry 4
entry 5
entry 6
1.0
0.5
0
400
500
600
700
800
wavelength (nm)
Figure 2. UV-vis spectra of poly(1-alt-2) in thin film. The entry number follows Table 2.
Table 2. Electronic properties of poly(1-alt-2).
2
2
4
5
4
5
Method Mn (PDI) 1
λ
λ
Eox
EHOMO
Ered
ELUMO
(opt/CV) 3
Entry
Eg
max
onset
1
2
3
4
5
DArP
DArP
DArP
DArP
Stille
15,700 (2.3)
17,000 (2.6)
22,700 (3.9)
44,900 (2.2)
17,700 (1.7)
53,800 (2.8)
637, 699
638, 700
638, 700
639, 701
636, 699
641, 702
747
746
747
753
748
747
1.66/1.73
1.66/1.74
1.66/1.75
1.65/1.74
1.66/1.76
1.66/1.73
0.53
0.54
0.54
0.54
0.54
0.56
−5.33
−5.34
−5.34
−5.34
−5.34
−5.36
−1.20
−1.20
−1.21
−1.20
−1.22
−1.17
−3.60
−3.60
−3.59
−3.60
−3.58
−3.63
6
Stille
Determined by GPC calibration based on polystyrene standards (entries 1–5: 140 ◦C, o-Cl2C6H4; entry 6: 150 ◦C,
1
2
3
1,2,4-Cl3C6H3). Values in nm; observed by UV-vis spectroscopy in thin films spin-coated on quartz plates. Values
in eV, estimated from the absorption onset (Eg = 1240/λonset) and cyclic voltammetry (EgCV). Onset potentials
opt
4
in V (vs. Fc/Fc+) for oxidation (Eox) and reduction (Ered). Values in eV, according to the following equation:
5
EHOMO = −4.80 − Eox; ELUMO = −4.80 − Ered
.
2.4. OFET Characteristics of Poly(1-alt-2)
OFET characteristics of the DArP polymers were compared with those of the Migita–Kosugi–Stille
cross-coupling products. OFET devices were fabricated on an n+-Si/SiO2 substrate treated with
n-octyltriethoxysilane (OTS) as a self-assembled monolayer (SAM). The active layer of poly(1-alt-2)
was formed by spin-coating from a CHCl3 or o-Cl2C6H4 solution, and sequential thermal annealing
was carried out at 240 ◦C for 30 min under an inert atmosphere. The solvents for spin-coating were
changed according to the solubility of polymers. We confirmed that the solvents little affected the
carrier mobility (Table S1).
Poly(1-alt-2) exhibited typical p-type characteristics under ambient conditions in the dark. Table 3
lists the hole mobility observed for the polymers shown in Table 2. The highest hole mobility was
observed for the DArP polymer in entry 1 (Mn = 15,700, µh = 0.31 cm2 V−1 s−1), and this value was
comparable to that for the Migita–Kosugi–Stille cross-coupling product with similar molecular weight
s
in entry 5 (Mn = 17,700, µh = 0.28 cm2 V−1 −1). On the other hand, the hole mobility for the other
polymers was low (entries 2–4 and 6). It emerges that the hole mobility depends on the weight average
molecular weight (Mw), not on the number average molecular weight (Mn). Indeed, the hole mobility
decreases significantly with increasing the Mw values.

Molecules 2018, 23, 981
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To understand the reasons behind the large variation in device performance depending on
molecular weight, polymer thin films formed on an OTS-treated substrate were investigated by
grazing incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM). These
investigations indicated that the hole mobility changes with the surface morphology rather than with
the crystallinity (Figures S4–S6). The GIWAXS analysis revealed the predominant edge-on orientation
on the substrate for all films. Moreover, in Table 3, the lamellar d-spacings (dl) and π–π stacking
distances (dπ) were very similar to each other, regardless of the Mw values and the polymerization
methods dl = 21.4(7) Å and dπ = 3.75(4) Å. On the other hand, in the AFM images, the surface
morphology clearly changed with Mw, and the polymer with a lower Mw value tended to form a
smoother surface. The polymers with a high Mw value in entries 4 and 6 showed several clear grain
boundaries, suppressing the carrier transport efficiency.
Table 3. OFET characteristics and ordering parameters for poly(1-alt-2).
Distance (Å) 5
Transistor Properties
1
1
−1 −1
2
4
6
7
Entry
Method
DArP
DArP
DArP
DArP
Stille
Mn
Mw
µh (cm2 V
s
)
Vth (V) 3
Ion/Ioff
dl
dπ
0.31
(0.21–0.37)
0.020
(0.013–0.030)
0.016
(0.012–0.022)
0.0030
−16 to
−5
102–108
102–108
103–106
104–107
102–107
>105
1
2
3
4
5
15,700
17,000
22,700
44,900
17,700
53,800 8
35,800
44,000
21.1
22.0
20.7
22.0
22.0
22.0
3.76
3.76
3.74
3.74
3.79
3.72
−15 to
−5
−21 to
−2
88,200
−29 to
−4
97,000
(0.0024–0.0033)
0.28
−29 to
−3
30,300
(0.15–0.51)
0.004
151,000 8
6
Stille
−6
(–) 9
1
Determined by GPC calibration based on polystyrene standards (140 ◦C, o-Cl2C6H4), unless otherwise stated.
2
3
4
Average mobilities for over 5 devices tested unless otherwise stated. The threshold voltage. The on/off current
5
6
ratio. Determined by GIWAXS analysis. d-Spacing to the lamellar structure of the edge-on crystallite, (100)
along the qz axis. d-Spacing to the
by GPC calibration and based on polystyrene standards (150 ◦C, 1,2,4-Cl3C6H3). Only one device showed FET
7
8
π
–π
stacking of the edge-on crystallites, (010) along the qxy axis. Determined
9
characteristics among the 12 devices fabricated.
While the hole mobility was little affected by the polymerization methods, the charge transfer
characteristics were clearly different for the DArP and Migita–Kosugi–Stille cross-coupling products.
In Figure 3a, the DArP polymer (entry 1, Table 3) has the ideal transfer characteristics, showing a
linear correlation in the current–voltage curve. Thus, this polymer exhibited a VG-independent change
in the hole mobility. A similar trend was observed for all DArP products (see Figure S2). On the
other hand, in Figure 3b, the Migita–Kosugi–Stille cross-coupling product (entry 5, Table 3) exhibited
non-ideal double slope characteristics [30], which are often related to the contact resistance and/or the
presence of carrier traps due to defects or impurities in the polymer transistors. The same phenomenon
has already been documented for the poly(
polymerization [22].
1-alt-2) prepared by Migita–Kosugi–Stille cross-coupling

Molecules 2018, 23, 981
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Figure 3. Charge transfer characteristics of the OFETs using poly(
Table 3 (VD = −60 V).
1-alt-2) of entries 1 (a) and 5 (b) in
3. Conclusions
We have described the synthesis of D-A polymers containing 1,2-dithienylethene (DTE) units via
palladium-catalyzed direct arylation polymerization (DArP). The reaction of dibromoisoindigo ( Br
and DTE ( ) using the catalytic system with P(2-MeOC6H4)3 (L1) as a ligand afforded the desired
poly( -alt-
) with a high molecular weight (Mn up to 44,900) and yield. The 1H-NMR analysis revealed
1-
)
2-H
1
2
a highly controlled structure for the resulting polymer. On the other hand, the 1H-NHR spectrum
of the Migita–Kosugi–Stille cross-coupling polymerization product indicated the contamination of
unknown structural defects. These polymers showed almost the same optical properties, independently
of the polymerization methods. Moreover, they exhibited comparable charge mobility when the
weight average molecular weight (Mw) was similar. However, the charge transfer characteristics
of the DArP product in OFET were superior to those of the Migita–Kosugi–Stille cross-coupling
product. The DArP product displayed an ideal linear relationship in the current–voltage curve,
whereas the Migita–Kosugi–Stille product showed a non-ideal double-slope curve. The so-called
double-slope characteristics have been recognized to be a crucial problem in the practical applications of
polymer-based OFETs [30]. Since the physical properties observed by spectroscopic and electrochemical
methods were almost the same, the difference in charge transfer characteristics of these products is
possibly due to the difference in structural defects. Moreover, there is a possibility that impurities
arising from tin reagents cause the deterioration in device performance. Thus, the present study
indicates that the highly selective synthesis of D-A polymers via DArP using P(2-MeOC6H4)3 (L1) as a
ligand provides a simple but powerful approach for developing OFETs with good properties.
4. Materials and Methods
4.1. General Considerations
All manipulations were performed under a nitrogen atmosphere using Schlenk techniques or
a glove box. Toluene, THF, and 2-MeTHF were dried over Na/Ph2CO, distilled, and stored over
activated MS4A. Cs2CO3 was dried overnight at 120 ◦C under vacuum and handled in a glove box.
PivOH was distilled and handled in a glove box. TMEDA was dried over CaH2 and distilled.
1-Br [31],
2
-
H
[
32], SnMe3 33], and Pd2(dba)3 CHCl3 [34] were prepared according to the literature. The other
2
-
[
·
chemicals were obtained from commercial sources and used without purification.
4.2. Direct Arylation Polymerization of 1-Br and 1-H
A typical procedure is reported for run 3 in Table 1. The compounds Cs2CO3 (195 mg, 0.60 mmol)
and pivalic acid (20.4 mg, 0.20 mmol) were placed in a 10 mL Schlenk tube equipped with a Teflon
screw cock in a glove box. Then,
1
-
Br (219 mg, 0.20 mmol),
2
-
H
(38.5 mg, 0.20 mmol), Pd2(dba)3
·
CHCl3
(1.0 mg, 1.0 mol), L1 (1.4 mg, 4.0
µ
µmol), and 2-MeTHF (0.4 mL) were added. The mixture was

Molecules 2018, 23, 981
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stirred at room temperature for 0.5 h, and next at 100 ◦C for 24 h. The mixture was cooled up to room
temperature, diluted with CHCl3 (100 mL), and washed with water (3 10 mL). The organic phase
×
was poured into a vigorously stirred MeOH (400 mL). A dark red precipitate was collected by filtration,
washed with MeOH, and dried under vacuum overnight. The product was subjected to Soxhlet
extraction with acetone and hexane, and next with o-Cl2C6H4 (100 mL) containing diethylammonium
diethyldithiocarbamate (10 mg). No colored substance remained in the extraction thimble. The
o-Cl2C6H4 extract was poured into a vigorously stirred MeOH (400 mL), to produce a dark red solid of
poly(1-alt-2), in >99% yield (231 mg, Mn = 22,700, Mw/Mn = 3.9).
1H-NMR (C2D2Cl4, 130 C, 600 MHz):
δ 9.26 (d, J = 8.1 Hz, 2H), 7.35 (d, J = 3.3 Hz, 2H), 7.32 (d,
◦
J = 8.5 Hz, 2H), 7.14–7.08 (m, 4H), 7.04 (s, 2H), 3.77 (br, 4H), 2.11–2.01 (br, 2H), 1.54–1.22 (m, 80H),
0.94–0.86 (m, 12H).
Supplementary Materials:
Supplementary materials including detailed experimental procedures,
characterizations of all new compounds and polymers, as well as additional figures and tables are available online.
Acknowledgments: This work was supported by KAKENHI (JP17H03055, JP15K17855, JP17K05883) from
Japan Society for the Promotion of Science and the ACT-C program of Japan Science and Technology Agency.
The GIWAXS experiments were performed on beamline BL46XU of SPring-8 with the approval of the Japan
Synchrotron Radiation Research Institute (JASRI) (Proposal 2017B1831). We are grateful to Atsushi Wakamiya
(ICR, Kyoto University) for analytical GPC assistance, Takeshi Hasegawa and Takafumi Shimoaka (ICR, Kyoto
University) for AFM assistance, and Itaru Osaka (Hiroshima University) and Tomoyuki Koganezawa (JASRI) for
the measurement of GIWAXS images. The NMR measurements (600 MHz spectrometer) were supported by the
Joint Usage/Research Center (JURC) at ICR, Kyoto University.
Author Contributions: M.W. and F.O. conceived and designed the experiments; M.W., N.Y., and H.M. performed
the experiments; M.W., N.Y., and F.O. prepared the manuscript; all authors discussed and commented on
the manuscript.
Conflicts of Interest: The authors declare no conflict of interest.
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