Influence of donor–acceptor conjugation between thiophene-phthalazinone structures containing Sp3 C?N bond on the frontier orbital levels and optic–electronic properties

Article abstract of DOI:10.1002/pola.28237

Herein, an electron-deficient phthalazinone unit containing a unique Sp³ hybrid nitrogen atom as an acceptor to cut off the ether bond was presented and three Donor–Acceptor (D–A) conjugated fluoropolymers via Classical Aromatic Nucleophilic Displacement Polymerization (CANDP) method were successfully synthesized. These polymers exhibit excellent thermostability. The 5% weight loss temperature of PDT2TF under nitrogen atmosphere is high, up to 470 °C. This is due to that the D–A conjugation between thiophene-phthalazinone units affects its resonance energy and stabilizes the thiophene-phthalazinone structures. These three fluoropolymers show strong absorptions and fluorescence in visible light region both in solution and thin film states. The band gaps (E_g) of these polymers are narrower than that of their corresponding di-NH capped monomers, owing to the good electronic communication properties of the Sp³ nitrogen atom in the phthalazinone unit. The E_g value of PDT3TF is decreased to 2.03 eV. These results indicate that phthalazinone unit is an efficient acceptor and could exhibit strong D–A effect with thiophene unit. Also, the Sp³ nitrogen atom in the phthalazinone shows good electronic wave function and charge transport properties. This facile CANDP synthetic method combined with Sp³ C?N bond linked electron-deficient phthalazinone unit affords polymers with controllable photoelectric properties.

Full text of DOI:10.1002/pola.28237

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Influence of Donor–Acceptor Conjugation Between
Thiophene-Phthalazinone Structures Containing Sp3 CAN Bond
on the Frontier Orbital Levels and Optic–Electronic Properties
Jianhua Han,1 ShengLi Cheng,1 Cheng Liu,1 Jinyan Wang,2 Xigao Jian2
1Polymer Science & Materials, Chemical Engineering College, Dalian University of Technology, Dalian, 116024, China
2State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China
Correspondence to: J. Wang (E-mail: wangjinyan@dlut.edu.cn)
Received 3 May 2016; accepted 14 July 2016; published online 00 Month 2016
DOI: 10.1002/pola.28237
ABSTRACT: Herein, an electron-deficient phthalazinone unit con-
taining a unique Sp3 hybrid nitrogen atom as an acceptor to
cut off the ether bond was presented and three Donor–Accep-
tor (D–A) conjugated fluoropolymers via Classical Aromatic
Nucleophilic Displacement Polymerization (CANDP) method
were successfully synthesized. These polymers exhibit excel-
lent thermostability. The 5% weight loss temperature of
PDT2TF under nitrogen atmosphere is high, up to 470 8C. This
is due to that the D–A conjugation between thiophene-
phthalazinone units affects its resonance energy and stabilizes
the thiophene-phthalazinone structures. These three fluoropol-
ymers show strong absorptions and fluorescence in visible
light region both in solution and thin film states. The band
gaps (Eg) of these polymers are narrower than that of their cor-
responding di-NH capped monomers, owing to the good
electronic communication properties of the Sp3 nitrogen atom
in the phthalazinone unit. The Eg value of PDT3TF is decreased
to 2.03 eV. These results indicate that phthalazinone unit is an
efficient acceptor and could exhibit strong D–A effect with thio-
phene unit. Also, the Sp3 nitrogen atom in the phthalazinone
shows good electronic wave function and charge transport
properties. This facile CANDP synthetic method combined with
Sp3 CAN bond linked electron-deficient phthalazinone unit
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affords polymers with controllable photoelectric properties.
2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym.
Chem. 2016, 00, 000–000
KEYWORDS: classical aromatic nucleophilic displacement poly-
merization; phthalazinone; thiophene; UV-vis spectroscopy;
thermal properties; structure-property relations
of non-doped polyaniline. Incorporating triphenylamine into
polymer backbones with p-conjugated system could obtain
excellent charge-transport, hole-transporting, and electrolu-
minescence properties with controllable band gaps.8–10,14
For the conjugated poly(4-cyanotriphenylamine), the optical
band gap is determined to be approximately 2.91 eV.12 How-
ever owing to the ammonia with three hydrogen atoms all
replaced by aryl groups, the three phenyl substituents are
non-coplanar.15,16 These Sp3 hybridized CAN bond could
partly weaken the electron delocalization along the polymer
backbone.9 Besides, as a family of Sp3 CAN bond linked
units, the Sp3 hybrid nitrogen atom in phthalazinone unit is
combined into a naphthalene ring, resulting in better planari-
ty than classical triangular pyramidal triphenylamine struc-
ture.17 Furthermore, the electron-drawing C@N and C@O
bond linked with electron-rich Sp3 nitrogen atom exhibits
better electron delocalization and charge transport proper-
ties. Generally, the conjugated effect is related to the bond
INTRODUCTION In the past decades, the intrinsic characteris-
tics of donor–acceptor (D–A) conjugated polymers containing
Sp3 CAN bond have been widely studied as important organ-
ic semiconductor materials for optoelectronic applications,
such as light-emitting diodes, polymer solar cells, and organ-
ic field effect transistors.1–13 The classical structures, such as
polyaniline and triphenylamine, are shown in Figure 1. Due
to its low-cost commercial available monomer, straightfor-
ward and high-yield synthetic method, polyaniline is a star
material since the very beginning in the optoelectronic
research field.1–7 However, the non-doped state of polyani-
line, which a saturated amine is linked with two conjugated
benzene rings and one hydrogen atom (Fig. 1), inhibits con-
jugation with large band gaps (3.6 eV).13 Also, polymeric
materials based on triphenylamine units have been widely
used as semiconductor materials for electro-optics applica-
8–12
tions.
The structure feature of triphenylamine is that the
electron-rich nitrogen atom links with three p-conjugated
length alternation (BLA) that
a geometrical parameter
phenyl groups, resulting in its narrower band gaps than that
Additional Supporting Information may be found in the online version of this article.
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FIGURE 2 Polymers synthesized by classical aromatic nucleo-
philic displacement polymerization. [Color figure can be
viewed in the online issue, which is available at wileyonlineli-
brary.com.]
FIGURE 1 The classical polymer structures containing Sp3
CAN bond. [Color figure can be viewed in the online issue,
which is available at wileyonlinelibrary.com.]
ion batteries and vanadium redox flow battery fields,22,23
etc. But a common drawback with the use of CANDP method
is to incorporate the ether bond in the polymer main chain.
This could lead to the interruption of electron delocalization
in the polymer backbone.26,45–48 Therefore, quite a few
CANDP polymers have exhibited excellent optoelectronic
properties. Developing new structure that can prolong the
conjugated effect along the polymer backbone via CANDP is
highly desirable for broadening the application of CANDP
method into optoelectronic materials field. To address this
problem, di-NH end-capped monomer containing phthalazi-
none structure was designed and synthesized.17 This strate-
gy is to eliminate the ether bond and enhance the electronic
communication through the Sp3 CAN bond. In the previous
report, these CAN coupling CANDP was unique and demon-
strated that the NAH group exhibited like a phenolic OAH
group in the phthalazinone structure.24,25,49 Although these
polymers, synthesized by CAN coupling CANDP, have been
reported.21,26,37,38 The optoelectronic properties, to our
knowledge, have never been investigated systematically in
the class of CANDP polymers containing D–A conjugated
system.
defined from the difference between the average lengths of
adjacent carbon–carbon bonds in D–A polymers.18 As can
been seen in Figure 1, the BLA influenced by the partial
charge redistribution from the conjugated effect is deter-
mined by DFT calculations.18,19 The BLA of benzene ring
linked with phthalazinone unit is 0.00382 Å, which is much
shorter than that of benzene ring in the polyaniline (0.00961
Å) and poly(triphenylamine) (0.00751 Å). This suggests that
phthalazinone could possess higher electron delocalization
within the molecule compared with phenylamine and poly(-
triphenylamine).18,19 As previously reported, the phthalazi-
none moiety is widely used to develop polymeric materials
for high temperature-resistant resins and fibers.20–26 These
high-performance phthalazinone-containing polymers have
exhibited good solubility and rigidity, even excellent thermal-
stability and mechanical properties.27–30 However, there has
been seldom focusing on the optoelectronic properties of the
phthalazinone structure. Thus, novel building D–A conjugat-
ed polymers with phthalazinone moiety is highly desirable
for investigating its optoelectronic properties deeply.
Based on above considerations, two new di-NH capped
monomers were successfully designed and synthesized. In
order to improve D–A conjugated effect and p–p stack inten-
sity of the phthalazinone-based polymers, more thiophene
units were introduced into the di-NH monomers (DT2 and
DT3 in Fig. 3), not limited to our previous reported mono-
mer (DT1). On the same principle as above, we introduced
more rigid structure (decafluorobiphenyl) than that of di-
From the polymer chemistry view point, phthalazinone-
based polymers are mainly synthesized by Classical Aromatic
Nucleophilic Displacement Polymerization (CANDP) through
the Sp3 hybridized NAH reactive site. The aromatic nucleo-
philic displacement reactions have received considerable
attention in polymer chemistry science as a promising classi-
cal polymerization method for achieving high molecular
weight polymers (see Fig. 2).31–33 Various kinds of polymers
have been developed based on CANDP.21,34–41 The CANDP is
rapid, less side reactions, low-cost base catalysis (K2CO3,
Cs2CO3, etc.), and yielded polymers of excellent rigid thermo-
plastics with high glass transitions.31 Generally, the polymer
synthesized by CANDP could be classified as shown in Figure
2. Polyarylether is the most important material in the family
of CANDP polymers via C-O coupling polymeriza-
tion.31,32,36,42 And the phthalazinone-based polyarylether has
been extensively studied and widely used as structural mate-
rial in the aerospace and automotive industries,30,40 func-
tional membranes for the optical waveguide applications,43,44
anion and proton exchange membrane materials in lithium-
FIGURE 3 The structures of designed and synthesized di-NH
capped D–A monomers.
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halogenated monomers containing ketone/di-ketone/sulfone
groups into the polymer main chains.17 Decafluorobiphenyl
has been widely used in the CANDP as a halide monomer
polymerized with various bisphenol monomer to achieve
high molecular polymers.27,43,44,50,51 This is the first time
that di-NH monomer polymerized with decafluorobiphenyl.
Thus, the polymerization conditions were optimized to avoid
a great degree of cross-linking and branching side reactions
and obtain high molecular polymers. The structures of D–A
polymers were fully characterized by relevant methods. Fur-
thermore, the thermal stability, photophysical properties,
electrochemical properties, DFT quantum chemical calcula-
tions, and morphology properties of monomers and poly-
mers were investigated in details. Since few researchers
investigated the optoelectronic properties of the CANDP pol-
ymers and phthalazinone-based polymers, a detailed study
on the structure–property relationship of monomers and pol-
ymers is fundamental to understand the optoelectronic prop-
erties of the Sp3 hybrid nitrogen atom in phthalazinone
moiety.
scanning calorimetry (DSC) analyzer with a heating rate of
10 8C/min from 30 8C to 300 8C under an inert N2 atmo-
sphere. The Tg value was taken from the mid-point. Cyclic
voltammetry measurements (CV) were performed on an
electrochemistry (BAS100W) workstation using a three elec-
trode cell. The polymer thin films were coated on the plati-
num stick working electrode. Platinum were used as the
counter electrode. An Ag/Ag1 electrode (containing 0.01 M
silver nitrate in CH3CN) was used as a reference electrode
analyzer. An anhydrous and N2-saturated dichloromethane
containing 0.1 M tetrabutylammonium hexafluorophosphate
was used as electrolyte. The ferrocene/ferrocenium (Fc/Fc1)
redox couple was used as an internal standard which occurs
at 10.07 V under these conditions. The Lowest Unoccupied
Molecular Orbital (LUMO) and Highest Occupied Molecular
Orbital (HOMO) energies were determined from the onset of
the first reduction peak assuming a formal potential of Fc/
Fc1 of 24.80 eV relative to vacuum level (scan rate 100
mV/s). Fluorescence studies were record using a Hitachi F-
4500 spectrofluorometer with a xenon lamp and 1.0 cm
quartz cells. Element analysis was carried out on a Vario
ELIII CHNOS Elementaranalysator from Elementaranalysesy-
teme GmbH. X-ray diffraction(XRD) experiments of polymer
thin films were determined on the a Bruker D8 using Cu-K
radiation source in the range of 2 Theta (18–408) with a
scanning rate of 28. The contact angle of polymer thin films
was measured on an optical contact angle measuring device
DSA100. Theoretical calculation was performed by using the
density functional theory (DFT) with the B3LYP/6-31G(d, p)
and LC-wPBE/6-31(d, p) basis set (Gaussian 09W).53
EXPERIMENTAL
Materials and Characterization
Unless otherwise stated, the starting materials were com-
mercially available and used without any further purification.
Solvent and other common reagents were obtained from
Shanghai Energy Chemical. Compounds 2 and DT1 were syn-
thesized as the previous reported.17 The solvents (THF, ether,
and toluene) was dried from benzophenone and sodium
under an inert N2 atmosphere, then distilled prior to use.
The NMP and DMAc were dried from CaH2 and distilled
before using. Compounds 4 were obtained from Dalian Poly-
mer New Material Co., LTD. 1H-NMR (400 MHz), 19F-NMR
(470 MHz), and 13C-NMR (100 MHz) spectra were recorded
on a Bruker spectrometer at 25 8C. And the NMR chemical
shifts were determined relative to the residual CDCl3 (7.26
ppm in 1H-NMR), DMSO-D6 (2.50 ppm in 1H-NMR), the 13C
resonance shift of CDCl3 (77.16 ppm), and the 19F resonance
shift of trifluoroacetic acid at 276.55 ppm.52 The number
average molecular weight and polydispersity index (PDI)
were determined on Agilent PL gel permeation chromatogra-
phy (GPC) 50 by using CHCl3 as eluent at 40 8C and polysty-
rene as standard, equipped with two Agilent PL gel 7.5 lm
MIXED-D column and one guard column. Matrix-assisted
laser desorption ionization time-of-fight mass spectroscopy
(MALDI-TOF-MS) analyses were collected on a Micro-mass
GC-TOF CA 156 MALDI-TOF-MS. Fourier Transform Infrared
Spectrometry (FT-IR) were performed on the Thermo-Nicolet
Nexus 470 (KBr pellet method). Ultraviolet–visible (UV–vis)
absorption spectra of polymers were determined in diluted
N-methyl-2-pyrrolidinone (NMP) solutions and thin films
coated on the glass slide using a PerkinElmer Lambda 700
spectrometer. Thermogravimetric analysis (TGA) was mea-
sured on a METTLER TGA/SDTA851 analyzer with a heating
rate of 20 8C/min from 30 8C to 800 8C under an inert N2
atmosphere. Measurements of the glass transition tempera-
ture (Tg) was performed on a METTLER DSC822 differential
Synthesis of Monomers
2,2’-Bithiophene(1)
A mixture of 2-bromothiophene (1) (10 mmol, 1.63 g) and
2 mol % equivalents of NiCl2(dppp) (0.5 mmol, 271 mg) in
10 mL anhydrous THF was brought under N2 atmosphere
before thiophen-2-ylmagnesium bromide (12 mmol, 2.25 g)
in 10 mL THF solution was dropwise during 20 min at 0 8C.
After string at 0 8C for 2 h, the mixture was then refluxed
and stirred during 24 hours. After cooling to room tempera-
ture (15 min), the mixture was quenched with 1 M HCl.
Then, the organic phase was extracted three more times
with CH2Cl2 (4 3 10 mL), dried over MgSO4, filtered, and
concentrated under vacuum. After purification by flash chro-
matography on silica gel in petroleum ether (Rf 5 0.7). The
desired product 1 was obtained in 89% yield. Light yellow
1
liquid. H NMR (400 MHz, CDCl3): d 7.31–7.19 (m, 2H), 7.07
(dt, J 5 4.9, 4.5 Hz, 1H). 13C NMR (101 MHz, CDCl3): d
137.43 (s), 127.84 (s), 124.39 (s), 123.81 (s).
4-(5’-(4-Oxo-3,4,4a,8a-tetrahydrophthalazin-1-yl)-[2,2’-
bithiophen] 25-yl)phthalazin-1(2H)-one (DT2)
DT2 were synthesized according to the reported procedure
by the Friedel–Crafts reaction of isobenzofuran-1,3-dione
with 2,2’-bithiophene(1) in the presence of anhydrous alumi-
num chloride.21 The crude product recrystallized from acetic
acid. After washed with ethanol, red solid was obtained in
1
81% yield. Red solid. H NMR (400 MHz, DMSO): d 12.99 (s,
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TABLE 1 The Synthetic Data of Fluorinated and Pi-Conjugated
2H), 8.36 (d, J5 7.5 Hz, 2H), 8.28 (d, J5 8.2 Hz, 2H), 8.02 (t,
J 5 7.6 Hz, 2H), 7.95 (t, J 5 7.5 Hz, 2H), 7.68 (d, J 5 3.9 Hz, 2H),
7.57 (d, J 5 3.9 Hz, 2H). HRMS-EI: M1 Calcd. For
C24H16N4O2S2: 454.0558; found: 454.0558. FTMS-Tof: [M 1 H]1
Calcd. For C24H17N4O2S2: 455.0631; Found: 455.0631. Elemen-
tal analysis: Calcd. For C24H16N4O2S2: C, 63.14; H, 3.53; N,
12.27%. Found: C, 62.61; H, 3.05; N, 11.68%. Melting Point:
not detected from 30 8C to 400 8C by DSC.
Polymers
a
Temp.
Mn
Yield
(%)b
Entry
Polymers
(8C)
(kDa)
PDIa
1
2
3
4
5
6
7
8
PDT1TF
110
90
11.4
6.8
16.8
–
1.68
2.02
4.22
–
88
64
87
44
32
–
PDT2TF-1
PDT2TF-2
PDT2TF-3
PDT2TF-4
PDT2TF-5
PDT3TF-1
PDT3TF-2
110
130
150
170
90
(3-Dodecylthiophene-2,5-diyl)bis(tributylstannane) (3)
To a stirred solution of 2,5-dibromo-3-dodecylthiophene (2)
(20 mmol, 4.85 g) in dried ether (40 mL) at 215 8C under
N2 atmosphere was dropwise added n-BuLi (2.4 M, 6.07 g,
8.4 mL). The mixture was stirred for 2 h at 0 8C and subse-
quently tri-n-butyltin chloride (1.2 equiv, 24.0 mmol, 2.75 g,
1.9 mL) in 20 mL ether was dropwise added. The mixture
was allowed to stir for 2 h at 0 8C before it was reached
room temperature for 6 h. The reaction mixture was diluted
with saturated sodium bicarbonate solution (40 mL) and
extracted with hexanes (5 3 10 mL). The combined organic
layers were washed dried over MgSO4. The solvent was
removed under reduced pressure. The light yellow liquid (3-
–
–
–
–
20.6
10.9
1.86
1.43
91
87
110
a
Determined by GPC using CHCl3 as eluent at 40 8C and polystyrene for
calibration.
b
After Soxhlet extraction and precipitation.
Synthesis of the Polymers
General Method for CANDP
About 1.0 equiv. di-NH monomer and 1.0 equiv. decafluorobi-
phenyl monomer was dissolved in anhydrous DMAc. About
0.2 equiv KF and 2.0 equvi CaH2 were added. Then the mix-
ture was allowed to stir at reaction temperature. Additional
solvent (DMAc) was necessary to be added when the viscosi-
ty of the mixture solution was increased to a high level. After
the viscosity of the mixture solution remained almost
unchanged during stirring at reaction temperature for 12 h.
The reaction mixture was poured into diluted HCl solution.
Then the collected solid was washed by Soxhlet extraction
with acetone (12 h), ethanol (12 h), and hexane (12 h). The
solid was dissolved in hot NMP and precipitated in excess
ethanol to obtain resulting polymer. Then calculate the yields
(Table 1). The images of final product are shown in Support-
ing Information Figure S9. The structures of polymers are
dodecylthiophene-2,5-diyl)bis(tributylstannane)
(3)
was
obtained with a yield of 96%. Used immediately without fur-
ther purification. Light brown liquid. 1H NMR (400 MHz,
CDCl3): d 7.31 (s, 1H), 2.86–2.78 (m, 2H), 1.86–1.01 (m,
77H). 13C NMR (101 MHz, CDCl3): d 151.51 (s), 141.99 (s),
137.38 (s), 136.77 (s), 33.10–10.50 (m).
4-(3’-Dodecyl-5’’-(4-oxo-3,4,4a,8a-tetrahydrophthalazin-
1-yl)-[2,2’:5’,2’’-terthiophen]-5-yl) phthalazin-1(2H)-one
(DT3)
A mixture of (3-dodecylthiophene-2,5-diyl)bis(tributylstan-
nane) (3) (0.2 mmol) and 2.5 equivalents of 4-(5-bromothio-
phen-2-yl)phthalazin-1(2H)-one (4) (0.5 mmol, 229 mg) in
10 mL anhydrous toluene/NMP(1:4) was brought under
argon atmosphere before 20 mol % of PdCl2(PPh3) (0.04
mmol, 46 mg) was added in one portion. The mixture was
then stirred at 110 8C during 24 h. After cooling to room
temperature (45 min), the mixture was poured into cold
methanol. Then the crude product was collected and dried
under vacuum. The desired product was recrystallized from
chloroform twice and washed with ethanol. Red yellowish
solid DT3 was obtained in 23% yield. Red yellowish solid.
1H NMR (400 MHz, DMSO): d 12.95 (d, J 5 3.9 Hz, 2H), 8.34
(d, J 5 7.8 Hz, 2H), 8.22 (d, J 5 8.0 Hz, 2H), 7.98 (t, J 5 7.5
Hz, 2H), 7.91 (t, J 5 7.5 Hz, 2H), 7.63 (d, J 5 3.8 Hz, 1H), 7.60
(d, J 5 3.8 Hz, 1H), 7.42 (d, J 5 3.7 Hz, 1H), 7.42 (d, J 5 3.7
Hz, 1H), 7.35 (s, 1H), 7.31 (d, J 5 3.7 Hz, 1H), 2.76 (t, J 5 7.6
Hz, 2H), 1.62 (dd, J 5 14.6, 7.2 Hz, 2H), 1.42–1.02 (m, 18H),
0.76 (t, J 5 6.8 Hz, 3H). 13C NMR (101 MHz, DMSO) d 158.85
(s), 140.78 (s), 139.62 (s), 137.12 (d, J 5 4.9 Hz), 136.44 (s),
136.06 (s), 134.10 (s), 133.84 (s), 131.77 (s), 129.33 (s),
128.99 (d, J 5 9.6 Hz), 127.85 (dd, J 5 19.5, 3.9 Hz), 126.32
(s), 125.79 (s), 124.54 (s), 79.20 (s), 31.28 (s), 29.67 (s),
29.39–28.55 (m), 22.07 (s), 13.87 (s). MALDI-TOF-MS: Calcd.
For C40H41N4O2S3: 705.24; Found: 705.08. Melting Point:
211 8C by DSC.
1
confirmed by H-NMR, 19F-NMR, GPC, and FT-IR.
RESULTS AND DISCUSSION
Monomer Structures and Synthesis
The di-NH monomers, namely, DT2 and DT3, were synthe-
sized as illustrated in Scheme 1. DT1 were synthesized as
the previous reported.17 2,2’-Bithiophene (1) were synthe-
sized via Kumada coupling reaction of 2-bromothiophene
with thiophen-2-ylmagnesium bromide. The desired product
1 was purified by flash chromatography. As 2,2’-bithiophene
is an electron-rich unit, di-acid intermediate was obtained
via the di-Friedel–Crafts reaction of the high activity 2,2’-
bithiophene with isobenzofuran-1,3-dione in the presence of
anhydrous aluminum chloride.21 The di-acid compound was
then converted to the di-NH product DT2 by directly reacted
with hydrazine hydrate in DMAc in excellent 81% yield. The
2,5-dibromo-3-dodecylthiophene (2) was distannylated and
Stille coupled with 4-(5-bromothiophen-2-yl)phthalazin-
1(2H)-one (4) in NMP/Toluene mixed solvent to form di-NH
compound DT3. The DT2 was purified by recrystallized in
NMP and washed with hot ethanol. The DT3 was purified by
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SCHEME 1 Synthesis of di-NH monomers containing phthalazinone-thiophene moiety.
recrystallized in CHCl3 twice and washed with methanol. As
shown in Figure 4, the assignments of proton in 1H-NMR
spectra are well agreement with the proposed structures.
Also, the chemical structures of the synthesized di-NH mono-
mers DT2 and DT3 were confirmed by other related technol-
ogies (see “Experimental” section).
Monomer Optical Properties
The normalized UV–vis absorption and emission spectra of
di-NH monomers in NMP solution are shown in Figure 6.
The maximum absorption wavelength of DT1, DT2, and DT3
are 349, 377, and 398 nm, respectively. The DT1 shows larg-
er conjugated backbone than DT2, but the maximum absorp-
tion wavelength of DT2 is red shifted relative to that of DT1.
That is attributed to the stronger donor ability and better
planarity (the h1 and h2 in Fig. 5) of thiophene units in DT2
(than benzene rings in DT1). As three thiophene rings are
To provide deep insight into the structural features of three
di-NH monomers, Figure 5 shows their details of molecular
geometries and frontier molecular orbital by DFT calcula-
tions, using the Gaussian 09w program at the B3LYP/6-
31G(d, p) level.53 As depicted in Figure 5, DT2 and DT3
exhibit the smaller h2 dihedral angle of 40.68 and 38.68 than
that of 44.78 in DT1 units, respectively. The result indicates
that thiophene unit exhibits better coplanarity with phthala-
zinone unit than that of benzene ring. Furthermore, the
smallest dihedral angle (h1 5 15.08), much smaller than that
of DT1 (h1 5 24.58) and DT3 (h1 5 16.88 and 28.18), is dis-
tinguished. Such small backbone torsion is resulted from
the small steric hindrance between two unalkyl substituents
thiophene rings. This better backbone coplanarity is benefi-
cial for improving the charge transport along the polymer
chains, increasing the intermolecular interaction, decreasing
the band gaps and expanding absorption.54,55 Additional,
the LUMO level is mainly distributed on the electron-
drawing phthalazinone unit. The HOMO level is mainly dis-
tributed on the electron–donor thiophene unit. The HOMO
and LUMO orbitals are also calculated using long-range Har-
tree–Fock (HF) corrections to the DFT functionals as imple-
mented in LC-wPBE (0%–100%) to characterize the
localized charged excitations of three di-NH monomers.56,57
As shown in Figure 5, the charged excitations along the
chain exhibited the similar location manners and trends,
compared with calculation results at B3LYP (20% HF
exchange) 6-31G(d, p) levels. The solvent effect on the local-
ized charged excitations of di-NH monomers are investigat-
ed. As depicted in Supporting Information Figure S21,
further addition of a polarizable solvent (acetonitrile) into
calculation could slightly reduce the band gaps and has no
substantial change in the HOMO and LUMO orbitals of di-
NH monomers. Overall, the design principles of di-NH
monomers should be beneficial to increasing the conjugated
effect and their optoelectronic applications.
FIGURE 4 The 1H-NMR spectra of DT2 and DT3 in DMSO-D6.
[Color figure can be viewed in the online issue, which is avail-
able at wileyonlinelibrary.com.]
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FIGURE 5 The calculated molecular geometries and HOMO/LUMO orbitals (vacuum) of di-NH monomers. [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.com.]
incorporated into the di-phthalazinone monomers, DT3
exhibits the largest red shift in UV–vis absorption in NMP
solution among three di-NH monomers. These suggest that
the phthalazinone unit, as a new acceptor, could combine
with thiophene unit (donor) to enhance the intramolecular
charge transfer and expand the absorption wavelength.
That’s all associated with yielded the low band gap polymers
for application in the optoelectronics field.58,59 Additional,
the maximum emission wavelength of DT1, DT2, and DT3
are 420, 477, and 498 nm, respectively. As shown in Figure
6(b), the fluorescent colors are blue, green, and yellow with
high fluorescence quantum yield (53%, 84%, and 69%,
respectively).17,60 These results indicate that more thiophene
units incorporated with phthalazinone unit could enhance
the D–A effects.
linking. The lower temperature could result in a linear poly-
mer with low degree of polymerization, owing to the highest
selectivity of the para-position fluorine atoms. In our previ-
ous report, the reactivity of NAH in phthalazinone unit is
lower than the common phenolic hydroxyl group (ArAOH),
the NAH reaction site could polymerize with the CAF bond
in decafluorobiphenyl at 908.44 In this article, the polymeri-
zation condition between DT2 with decafluorobiphenyl is
performed to obtain the high molecular weight polymer.
First, the polymerization proceeds under the conditions
before (KF/CaH2 in DMAc at 90 8C). However, the viscosity
of reaction solution did not increase dramatically after 60 h.
The molecular weight of PDT2TF-1 is only 6.8 kDa. We can
infer that di-NH monomers show lower reactivity than 4-(40-
Hydroxyphenyl)phthalazin-1(2H)-one (both ArAOH and NH
reaction sites) in the polymerization.28,44 Thus, the tempera-
ture of polymerization is increased to 110 8C. The viscosity
of reaction solution gradually increases after stirring 2 h at
110 8C. After adding DMAc three times, the viscosity of solu-
tion did not increase dramatically after stirring 12 h. The
molecular weight of PDT2TF-2 is 16.8 kDa. When the poly-
merization temperature increased to 130 8C, 150 8C, or 170
8C, the product precipitate from the reaction mixture before
the viscosity of solution reach to a certain extent. This is
because of forming a large degree of cross-linked product.
As shown in Figure 7, due to the asymmetrical phthalazi-
none unit, the fluorine signal at 137 ppm split into two
peaks in the 19F-NMR spectra of these fluoropolymers (the
Polymer Synthesis and Characterization
The polymerization of bisphenol monomers with decafluoro-
biphenyl has been previously reported in many literatures,
in
which
they
obtained
linear
polymer
prod-
ucts.28,29,43,44,50,51,61–63 However, this is the first time that di-
NH monomers are polymerized with decafluorobiphenyl
(Scheme 2). In order to avoid forming a large degree of
branched and cross-linked structures, the optimized poly-
merization conditions are investigated and shown in Table 1.
Generally because of the high reactivity of all fluorine atoms
in decafluorobiphenyl structure, the high temperature could
lead to more side reactions such as branching and cross-
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similar results can be observed in ref. 27).27 And the 19F-
NMR spectra of PDT2TF (different entries) indicate that the
most appropriate polymerization temperature is 110 8C
(entry 3). The lower temperature (90 8C, entry 2) results in
the low molecular weight product with unreacted terminal
groups. The higher temperature (130 8C or 150 8C) results in
more branched and crosslinked products with lower yield
after general purification steps. When the polymerization
temperature reached 170 8C, the product is precipitated
from the solution in 2 h. Also, Figure 8 shows the 1H-NMR
spectra of PDT2TF in different entries. The proton signals
are well consistent with the proposed structures. That sug-
gests that the side reaction is occurred at the CAF bond in
decafluorobiphenyl unit. Above all, even though this condi-
tion needs a long reaction time (>60 h), the optimized tem-
perature of polymerization of DT2 and decafluorobiphenyl is
110 8C (entry 3).The polymerization of DT1 and decafluoro-
biphenyl is conducted under the optimized condition (entry
1, 110 8C). The molecular weight of PDT1TF is 11.4 kDa
(PDI 5 1.68). The 1H-NMR and 19F-NMR spectra are shown
in Supporting Information Figure S6 and S7.
Furthermore, the PDT3TF was synthesized under two differ-
ent polymerization conditions (90 8C, entry 7 and 110 8C,
entry 8). As shown in Figure 9, unlike PDT2TF, the lower
polymerization temperature of PDT3TF tends to achieve
higher molecular weight polymers and more linear struc-
tures. As the Tg of PDT2TF and PDT1TF are not detected
from 30 8C to 300 8C, the Tg of PDT3TF is 120 8C. We sus-
pect that the more flexibility polymer backbone of PDT3TF
lead to higher reactive end group than that of PDT2TF. Thus,
the chain-propagating step could occur in low temperature
(in entry 7, 90 8C). The molecular weight of PDT3TF-1 is
20.6 kDa, higher than that of PDT3TF-2 (10.9 kDa). The 1H-
NMR spectra is shown in Supporting Information Figure S8.
Also, the images of obtained polymers in different entries
are shown in Supporting Information Figure S9. Due to the
large conjugated effect of polymer backbones, we can
FIGURE 6 The normalized UV–vis absorption (a) and emission
(b) spectra of di-NH monomers in NMP solution. [Color figure
can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
SCHEME 2 Polycondensation of decafluorobiphenyl with di-NH monomers.
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and PDT3TF-1(simply “PDT3TF” for short) are used for the
subsequent studies.
Thermal Properties of Polymers
The thermal decomposition property and glass transition
temperature of polymers are investigated by TGA and DSC
measurements under N2 atmosphere. The results are sum-
marized in Table 2 (details in Supporting Information Figs.
S10 and S11). The 5% weight-loss temperature (Td5%) of
PDT1TF, PDT2TF, and PDT3TF are 460 8C, 470 8C, and 468
8C, respectively. The char yield (Cy: the weight loss at 800
8C) of polymers is PDT1TF > PDT2TF > PDT3TF. That is
exactly consistent with the content of heteroatoms in poly-
mer chains. As shown in Table 2, for PDT1TF, no glass transi-
tion behavior is observed. The Tg of PDT2TF and PDT3TF is
288 8C and 120 8C. The results suggest that incorporating
thiophene units into phthalazinone-containing polymers
could decrease the glass transition temperature. Further-
more, lower Tg indicates the polymer end groups could
exhibit higher reactivity during polymerization. Not like
PDT2TF, the PDT3TF in Entry 7 (synthesized at 908) shows
higher enough molecular weight than that of Entry 8. That’s
owing to its low Tg value and more flexibility of the PDT3TF
backbones. The polymerization condition depends on not
only the activation energy of reaction functional group, but
also the mobility and flexibility of the polymer chains.
FIGURE 7 The 19F-NMR spectra of PDT2TF in CDCl3.
observe that the more linear structure and higher molecular
weight results in deeper color of product.
FT-IR Characterization of Polymers
The chemical structures of synthesized polymers in different
entries are also verified by FT-IR (Fig. 10). The stretching
FT-IR absorbing in around 1492 cm21 is detected for all
obtained polymers, on the account of the stretching vibration
of C@C in benzene ring (decafluorobiphenyl). The absorption
peak near 978 cm21 obviously appears after polymerization.
This signal is attributed to the stretching vibration of CAF in
decafluorobiphenyl unit. As shown in Figure 10(c), the signal
near 2800 cm21 is contributed by the stretching vibration of
the alkyl side-chains in DT3 units. Hereafter, it is worth men-
tioning that PDT1TF, PDT2TF-2 (simply “PDT2TF” for short),
The thermal decomposition property and melting point are
depicted in Table 2. With incorporating more thiophene units
into DT3 monomer, the melting point of DT3 (211 8C) is low-
er than that of DT1 and DT2 (>350 8C). The weak bond in
the structures could decrease the Td5% values. Thus the poly-
mers containing thiophene units (CAS bond) exhibit lower
Td5% value than that of polymers containing fully-phenyl
structure.64 Also, the Td5% value of polymers containing
phthalazinone moiety is higher than that of polymers con-
taining thiophene units.29,30,38 However, with incorporating
more poor thermostability thiophene units (compared with
benzene and phthalazinone units) into monomers, the order
FIGURE 9 The 19F-NMR spectra of PDT3TF in CDCl3. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
FIGURE 8 The 1H-NMR spectra of PDT2TF in CDCl3. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
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TABLE 2 The Thermal Data of Synthesized Polymers
Polymers
Td5% (8C)
Cy (%)a
Tg (8C)
PDT1TF
PDT2TF
PDT3TF
DT1b
460
470
468
403
407
419
69
67
66
33
58
42
>300
288
120
>350c
>400c
211c
DT2
DT3
The char yield at 800 8C in N2 atmosphere.
The data of DT1 is from ref. 17.
The melting point of di-NH monomers (details see Supporting Informa-
tion Figs. S12 and S13).
of Td5% values is DT3 > DT2 > DT1. We deduce that thio-
phene units combined with phthalazinone units could show
better conjugation effect than benzene ring. This will endow
the di-NH monomers with the higher resonance energy along
the structures.20 Although, PDT3TF contains three thiophene
units and alkyl side chains, the Td5% of PDT3TF is high as
419 8C. Besides, the Cy value of monomers at 800 8C is in
the range of 33%–58%, lower than that of their correspond-
ing polymers. This result could confirm that the decafluoro-
biphenyl is successfully polymerized with di-NH monomers.
Contact Angles Measurements
The water contact angle tests are carried out to investigate
the surface tensions of obtained polymers containing decaf-
luorobiphenyl units. The polymer thin films were casted on
glass slides from NMP solutions. As shown in Figure 11, the
water contact angles of synthesized polymers films are
92.928 (PDT1TF), 91.568 (PDT2TF), and 94.808 (PDT3TF).
These values are higher than that of PDS (56.198),17
FIGURE 10 The FT-IR spectra of polymers. [Color figure can be
viewed in the online issue, which is available at wileyonlineli-
brary.com.]
FIGURE 11 Contact angles of synthesized polymers. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
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FIGURE 12 The optimized structures and front molecular orbitals (vacuum) of synthesized polymers. [Color figure can be viewed
in the online issue, which is available at wileyonlinelibrary.com.]
indicating that hydrophobic decafluorobiphenyl unit is suc-
cessfully introduced into the polymer backbones.
calculated results show that the D–A effect of phthalazinone
units and thiophene units in PDT1TF is rarely observed. The
solvent effect on the localized charged excitations along the
polymer backbones are also investigated. As shown in Sup-
porting Information Figure S22, addition of a polarizable
medium (acetonitrile) into calculation exhibits no substantial
change in the HOMO and LUMO orbitals of polymers back-
bone and slightly reduce the band gaps corresponding with
the calculation results of di-NH monomers (in Supporting
Information Fig. S21).
DFT Calculations of Polymers
To gain deep insight into the structure-electronic relationship
of synthesized polymers, DFT calculations are performed
using B3LYP/6-31G(d, p) and LC-wPBE/6-31(d, p) meth-
od.53,56,57 The optimized geometrical structures and front
molecular orbitals of three polymers are shown in Figure 12.
It is clearly observed that all LUMOs are delocalized on the
strong electron deficiency phthalazinone units. As discussed
in later parts, the PDT2TF and PDT3TF show boarder
absorption range, larger emission wavelength and narrower
band gaps. The HOMOs of PDT2TF and PDT3TF are delocal-
ized on the electron-rich thiophene units. Thus the strong D–
A effect could occur.54,59 However, due to the distorted struc-
ture between benzene and phthalazinone units, the HOMOs
of PDT1TF are mainly delocalized on the decafluorobiphenyl
units. As shown in Figure 12, the electron transfer of
PDT1TF is limited into one segment. In this case the DFT
Figure 13 shows the calculated BLA of decafluorobiphenyl
units along the polymer backbones. The B3YLP exhibits the
higher overall BLA compared with LC-wPBE (0%–100%).
Even though, the calculation model is consisting of two
repeat units. As results calculated by LC-wPBE functional
model and previously reported by Nayyar,57 the BLA at the
middle of the chain(repeat unit size is 2, 3, 4) is lower than
that at the end of the chain(repeat unit size is 1). This trend
could also be observed by the inclusion of a solvent effect
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Sp3 CAN bond in the phthalazinone could expand the conju-
gated length and increase the intramolecular charge transfer
effect. Also, the maximum emission wavelength of polymers
in thin films states are moving toward long wave region, rel-
ative to that of polymers in NMP solution. Furthermore, the
maximum emission wavelength of PDT2TF in film states is
543 nm, consistent with the values of PDT3TF. This is sug-
gested that PDT2TF could form strong p–p stacking and
intermolecular interaction among the polymer backbone in
film states.
Electrochemical Property of Polymers
To evaluate the LUMO and HOMO levels of synthesized poly-
mer thin films, the reduction and oxidation potentials are
determined by cyclic voltammetry. The CV curves are shown
FIGURE 13 The BLA of decafluorobiphenyl units along the
polymer chains computed using B3LYP/6-31G(d, p) and LC-
wPBE/6-31G(d, p) basis set. The solvent effect studies are cal-
culated at LC-wPBE/6-31G(d, P) optimized levels. [Color figure
can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
(acetonitrile) through calculations. These results could
emphasize on the location of the trapping of charged excita-
tions along the chain.57,65
Optical Property of Polymers
The UV–vis absorption and photoluminescence spectra of
synthesized polymers are shown in Figure 14. The maximum
absorption wavelength of polymers in NMP solutions are
360 (PDT1TF), 380 (PDT2TF), and 396 nm (PDT3TF). The
order of these values corresponds well with the order of the
absorption values of their di-NH monomers. This is strongly
suggested that the conjugated length could be expanded by
the strong D–A effect between thiophene and phthalazinone
units. Due to the p–p stacking and the intermolecular charge
transfer effect, comparing with polymers in NMP solutions,
the thin films of PDT1TF and PDT2TF show bathochromic in
the optical absorption spectra [Fig. 14(a)]. However, the
PDT3TF film shows a hypochromatic effect. That can be
attributed to the long alkyl chain weaken the p–p stacking
and the intermolecular aggregation in film states.
The photoluminescence spectra of obtained polymers are
presented in Figure 14(b). The maximum emission wave-
length of polymers in NMP solutions are 435 (PDT1TF), 470
(PDT2TF), and 525 nm (PDT3TF), with enough fluorescence
quantum yield (50%, 14%, and 8%, respectively). The order
of these values corresponds well with the order of the emis-
sion values of their di-NH monomers. These data also indi-
cate the conjugated length could be efficiently extended by
the strong D–A effect between thiophene and phthalazinone
units. In another fact, the maximum emission wavelengths in
NMP solution are both largely redshifted than that of corre-
sponding di-NH monomers. These results demonstrate that
FIGURE 14 UV–vis absorption (a) and photoluminescence (b)
spectra of polymers in NMP solution and thin film states. [Col-
or figure can be viewed in the online issue, which is available
at wileyonlinelibrary.com.]
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CONCLUSIONS
TABLE 3 The Electrochemical Characteristics of Synthesized
Monomers and Polymers
We have incorporated electron-deficient phthalazinone moi-
ety into alternating D–A conjugated polymers containing
thiophene and decafluorobiphenyl units via classical aro-
matic nucleophilic displacement CAN coupling polymeriza-
tion. Remarkably, the molecular weight depends on not
only the NAH activities for polymerization but also the
mobility and flexibility of the polymer backbones. By opti-
mum polymerization conditions, the Mn of three hydropho-
bicity linear D–A conjugated polymers are 11.4, 16.8, and
20.6 kDa. The thermostability of di-NH monomers and poly-
mers are increased with the increase of the resonance ener-
gy along thiophene-phthalazinone (D–A) structures.
Improving coplanarity of di-NH monomers by introducing
thiophene unit directly connected to electron-deficient
phthalazinone unit could enhance the D–A conjugated
effect. Furthermore, removing ether bond in CANDP poly-
mers affords finely mixed D–A conjugated networks, result-
ing in broader absorption, longer emission wavelength and
narrower band gaps. The PDT2TF exhibits strong batho-
chromic shift effect both in UV–vis absorption and PL spec-
tra. However, the PDT3TF shows the blue shift from
solution states to film states in UV–vis absorption spectrum.
The XRD results suggest that introducing the long alky side
chain could significantly change the morphology of poly-
mers in film states.
Polymers
HOMO (eV)a
LUMO (eV)a
Eg (eV)a
Eg (eV)b
PDT1TF
PDT2TF
PDT3TF
DT1c
25.76
25.70
25.61
25.87
26.06
25.83
23.50
23.54
23.58
22.79
23.66
23.55
2.26
2.16
2.03
3.08
2.40
2.28
2.50
2.46
2.36
2.63
2.47
2.37
DT2
DT3
a
Determined by cyclic voltammetry (CV).
b
c
Estimated by DFT calculation at LC-wPBE/6-31G(d, p) levels.
Ref. 17.
in Supporting Information Figures S14 and S15. The corre-
sponding data are presented in Table 3. As can be seen from
Figure 12, the LUMO orbitals of three polymers are mainly
localized on the phthalazinone moiety. Thus the LUMO levels
are very similar for three polymers (23.50 to 23.58 eV). With
incorporating more thiophene units into polymer backbones,
the HOMO levels of polymers are increasing that the order is
25.76 eV(PDT1TF)< 25.70 eV(PDT2TF)< 25.61 eV
(PDT3TF). Accordingly coplanar structure and strong D–A
effect of thiophene-phthalazinone units are beneficial to inter-
molecular interaction, p–p stacking, and charge-transfer prop-
erties. Therefore the Eg values of polymers are 2.26 (PDT1TF),
2.16 (PDT2TF), and 2.03 eV (PDT3TF). Also, the calculated
band gaps are listed in Table 3. As previous reported, the
band gaps calculated by LC-wPBE/6-31G(d, p) basis set are
more approach the experiment results than those calculated
by B3LYP/6-31G(d, p) basis set.56 The results, predicted by
DFT theory, are basically consistent with the experiment ones.
In another hand, the experimental and calculated Eg values of
polymers are basically reduced relative to its corresponding
monomers, confirming the Sp3 CAN bond in the phthalazinone
units could prolong the conjugated length via CANDP method.
Summarizing, most of classical aromatic nucleophilic dis-
placement polymerization contains CAO linkage along the
polymer backbones. In general, ether bond limits the delocal-
ization of the electronic wave function and charge transport
properties. Herein, the di-NH monomers, derived from phtha-
lazinone structure, exhibit outstanding D–A conjugated effect.
The Sp3 CAN linkage shows fine delocalization of the elec-
tronic wave function along the chains. Future works mainly
progress with phthalazinone-based new materials (not just
decafluorobiphenyl as di-halide monomer) and its applica-
tions in the organic electronic fields.
Thin Film Morphology of Polymers
To investigate the relationship between electrical-optical prop-
erties and film microstructure, the XRD measurement is car-
ried out on thin films. No sharp crystalline signal could be
observed for the three polymers in Figure 15. However, the
difference of peak intensities (2h 5 208ꢀ308) can be distin-
guished, suggesting the various morphologies of polymers in
thin film states. And the strength of p–p stacking are
PDT2TF> PDT1TF> PDT3TF. Thus, the thin film of PDT2TF
shows broad absorption in UV–vis spectra (Figure 14). As we
known, strong D–A effect, good coplanar structure, and better
p–p stacking manner could provide benefit effect on intermo-
lecular charge transfer, widening absorption ranges, extension
emission wavelength and narrowing the band gap.66–68 Fur-
thermore, the difference of the maximum emission wavelength
in thin films and in NMP solutions Dk (kemfilm 2 kemsolution) for
PDT1TF, PDT2TF, and PDT3TF are 58, 73, and 18 nm. These
optical data coincide well with the XRD results.
FIGURE 15 XRD patterns of polymer thin films coated from
NMP solution. [Color figure can be viewed in the online issue,
which is available at wileyonlinelibrary.com.]
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ACKNOWLEDGMENTS
29 G. H. Li, J. Y. Wang, G. P. Yu, X. G. Jian, L. H. Wang, M. S.
Zhao, Polymer 2010, 51, 1524–1529.
The present study was financially supported by the National
Natural Science Foundation of China (no. 21074017 and
51273029). The authors acknowledge the Supercomputer Cen-
ter of Dalian University of Technology for providing computing
resources.
30 G. P. Yu, C. Liu, H. X. Zhou, J. Y. Wang, E. C. Lin, X. G.
Jian, Polymer 2009, 50, 4520–4528.
31 W. F. Hale, A. G. Farnham, R. N. Johnson, R. Clendinn, J.
Polym. Sci. Part A1 1967, 5, 2399–2399.
32 A. Hay, In Fortschritte der Hochpolymeren-Forschung;
Springer: New York, 1967; pp 496–527.
33 J. F. Burnett, R. E. Zahler, Chem. Rev. 1951, 49, 273–412.
REFERENCES AND NOTES
34 I. S. Chung, S. Y. Kim, J. Am. Chem. Soc. 2001, 123, 11071–
11072.
1 O. Kwon, M. L. McKee, J. Phys. Chem. B 2000, 104, 1686–
1694.
35 J. Hedrick, R. Twieg, T. Matray, K. Carter, Macromolecules
1993, 26, 4833–4839.
2 A. J. Heeger, Angew. Chem. Int. Ed. 2001, 40, 2591–2611.
3 A. J. Heeger, Rev. Mod. Phys. 2001, 73, 681–700.
36 T. Takekoshi, J. G. Wirth, D. R. Heath, J. E. Kochanowski, J.
S. Manello, M. J. Webber, J. Polym. Sci. Part A: Polym. Chem.
1980, 18, 3069–3080.
4 S. Stafstrom, J. L. Bredas, A. J. Epstein, H. S. Woo, D. B.
Tanner, W. S. Huang, A. G. Macdiarmid, Phys. Rev. Lett. 1987,
59, 1464–1467.
37 A. A. Mir, S. Matsumura, A. R. Hlil, A. S. Hay, Acs Macro
Lett. 2012, 1, 194–197.
5 S. Saravanan, M. R. Anantharaman, S. Venkatachalam, D. K.
Avasthi, Vacuum 2007, 82, 56–60.
38 S. Yoshida, A. S. Hay, Macromolecules 1995, 28, 2579–2581.
39 C. R. Mason, L. Maynard-Atem, K. W. Heard, B. Satilmis, P.
M. Budd, K. Friess, M. Lanc, P. Bernardo, G. Clarizia, J. C.
Jansen, Macromolecules 2014, 47, 1021–1029.
6 B. Wessling, Synth. Met. 1998, 93, 143–154.
7 A. G. MacDiarmid, Synth. Met. 1997, 84, 27–34.
8 H. Y. Lin, G. S. Liou, J. Polym. Sci. Part A: Polym. Chem.
2009, 47, 285–294.
40 Y. Shi, R. A. Weiss, Macromolecules 2014, 47, 1732–1740.
41 A. R. Hlil, S. Matsumura, A. S. Hay, Macromolecules 2008,
41, 1912–1914.
9 S. Roquet, A. Cravino, P. Leriche, O. Aleveque, P. Frere, J.
Roncali, J. Am. Chem. Soc. 2006, 128, 3459–3466.
42 T. Takekoshi, J. Wirth, D. Heath, J. Kochanowski, J.
Manello, J. Webber, Abstr. Pap. Am. Chem. Soc. 1979, 127–
127.
10 M. H. Sun, J. Li, B. S. Li, Y. Q. Fu, Z. S. Bo, Macromolecules
2005, 38, 2651–2658.
11 T. Manifar, S. Rohani, Can. J. Chem. Eng. 2004, 82, 323–334.
12 J. H. Wu, G. S. Liou, Adv. Funct. Mater. 2014, 24, 6422–6429.
43 Y. Song, J. Y. Wang, G. H. Li, Q. M. Sun, X. G. Jian, J.
Teng, H. B. Zhang, Polymer 2008, 49, 724–731.
13 R. P. Mccall, J. M. Ginder, J. M. Leng, H. J. Ye, S. K.
Manohar, J. G. Masters, G. E. Asturias, A. G. Macdiarmid, A. J.
Epstein, Phys. Rev. B 1990, 41, 5202–5213.
44 Y. Song, J. Wang, G. Li, Q. Sun, X. Jian, J. Teng, H. Zhang,
Polymer 2008, 49, 4995–5001.
45 H. Vonseggern, P. Schmidtwinkel, C. Zhang, H. W. Schmidt,
Macromol. Chem. Phys. 1994, 195, 2023–2037.
14 J. H. Wu, W. C. Chen, G. S. Liou, Polym. Chem. 2016, 7,
1569–1576.
46 A. A. G. Shaikh, A. R. Hlil, P. A. Shaikh, A. S. Hay, Macromo-
lecules 2002, 35, 8728–8737.
15 V. A. Naumov, S. Samdal, A. V. Naumov, S. Gundersen, H.
V. Volden, Russ. J. Gen. Chem. 2005, 75, 1956–1961.
47 Y. Meng, A. Yousef, A. R. Hlil, A. S. Hay, Macromolecules
2000, 33, 9185–9191.
16 Y. Shirota, J. Mater. Chem. 2000, 10, 1–25.
17 J. H. Han, K. Y. Yuan, C. Liu, J. Y. Wang, X. G. Jian, Rsc
Adv. 2015, 5, 30445–30455.
48 Y. Liu, Y. Qi, A. R. Hlil, Y. Meng, A. S. Hay, J. Polym. Sci.
Part a: Polym. Chem. 2009, 47, 4326–4331.
18 S. R. Marder, Chem. Commun. 2006, 131–134.
49 J. Y. Wang, Y. Gao, A. R. Hlil, A. S. Hay, Macromolecules
2008, 41, 298–300.
19 Y. Liu, M. Kong, Q. Zhang, Z. Zhang, H. Zhou, S. Zhang, S.
Li, J. Wu, Y. Tian, J. Mater. Chem. B 2014, 2, 5430.
50 K. Endo, T. Yamade, Polym. J. 2008, 40, 212–216.
20 G. Yu, C. Liu, J. Wang, X. Li, X. Jian, Polym. Degrad. Stab.
2010, 95, 2445–2452.
51 J. F. Ding, M. Day, G. P. Robertson, J. Roovers, Macromol.
Chem. Phys. 2004, 205, 1070–1079.
21 S. Yoshida, A. S. Hay, Macromolecules 1997, 30, 2254–2261.
52 P. A. Luchette, R. S. Prosser, C. R. Sanders, J. Am. Chem.
Soc. 2002, 124, 1778–1781.
22 S. H. Zhang, B. G. Zhang, D. B. Xing, X. G. Jian, J. Mater.
Chem. a 2013, 1, 12246–12254.
53 M. Frisch, G. Trucks, H. Schlegel, G. Scuseria, M. Robb, J.
Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.
Petersson. Gaussian Inc., Wallingford, CT, 2009.
23 S. H. Zhang, B. G. Zhang, G. F. Zhao, X. G. Jian, J. Mater.
Chem. a 2014, 2, 3083–3091.
24 N. Berard, A. S. Hay, Abstr. Pap. Am. Chem. Soc. 1993, 205,
281.
54 C. Li, Z. Mao, H. Chen, L. Zheng, J. Huang, B. Zhao, S. Tan,
G. Yu, Macromolecules 2015, 48, 2444–2453.
25 N. Berard, M. Paventi, K. P. Chan, A. S. Hay, Macromol.
Symp. 1994, 77, 379–388.
55 L. Han, W. Chen, T. Hu, J. Ren, M. Qiu, Y. Zhou, D. Zhu, N.
Wang, M. Sun, R. Yang, ACS Macro Lett. 2015, 361–366.
26 S. J. Wang, Y. Z. Meng, A. R. Hlil, A. S. Hay, Macromole-
cules 2004, 37, 60–65.
56 I. H. Nayyar, E. R. Batista, S. Tretiak, A. Saxena, D. L. Smith,
R. L. Martin, J. Chem. Theory Comput. 2013, 9, 1144–1154.
27 X. H. Li, Y. Gao, Q. Long, A. S. Hay, J. Polym. Sci. Part A
Polym. Chem. 2014, 52, 1761–1770.
57 I. H. Nayyar, E. R. Batista, S. Tretiak, A. Saxena, D. L. Smith,
R. L. Martin, J. Phys. Chem. Lett. 2011, 2, 566–571.
28 J. Y. Wang, G. H. Li, X. G. Jian, M. S. Zhao, Polym. Int.
2012, 61, 711–718.
58 J. Yao, Z. Cai, Z. Liu, C. Yu, H. Luo, Y. Yang, S. Yang, G.
Zhang, D. Zhang, Macromolecules 2015, 48, 2039–2047.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 00, 000–000
13

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
59 J. Z. Ren, X. C. Bao, L. L. Han, J. X. Wang, M. Qiu, Q. Q.
Zhu, T. Hu, R. Y. Sheng, M. L. Sun, R. Q. Yang, Polym. Chem.
2015, 6, 4415–4423.
64 C. Y. Yu, C. P. Chen, S. H. Chan, G. W. Hwang, C. Ting,
Chem. Mater. 2009, 21, 3262–3269.
65 S. Tretiak, A. Saxena, R. L. Martin, A. R. Bishop, Phys. Rev.
Lett. 2002, 89,
60 C. A. Heller, R. A. Henry, B. A. Mclaughlin, E. B. Dan, J.
Chem. Eng. Data 1973, 19, 214–219.
66 H. F. Yao, H. Zhang, L. Ye, W. C. Zhao, S. Q. Zhang, J. H.
Hou, Macromolecules 2015, 48, 3493–3499.
61 K. Miyatake, K. Oyaizu, E. Tsuchida, A. S. Hay, Macromole-
cules 2001, 34, 2065–2071.
67 C. Li, N. H. Zheng, H. J. Chen, J. Y. Huang, Z. P. Mao, L. P.
Zheng, C. Weng, S. T. Tan, G. Yu, Polym. Chem. 2015, 6, 5393–
5404.
62 Y. Song, G. H. Li, J. Y. Wang, Q. M. Sun, X. G. Jian, J.
Teng, H. B. Zhang, Polym. J. 2008, 40, 92–93.
63 G. H. Li, J. Y. Wang, G. X. Su, X. G. Jian, L. H. Wang, M. S.
Zhao, Polym. J. 2010, 42, 880–886.
68 L. Yang, Y. Y. Yu, Y. L. Gong, J. R. Li, F. J. Ge, L. Jiang, F.
Gao, Y. Dan, Polym. Chem. 2015, 6, 7005–7014.
14
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 00, 000–000