Two novel fluorinated poly(arylene ether)s with pendant chromophores for second-order nonlinear optical application

Article abstract of DOI:10.1021/ma048889h

Two fluorinated poly(arylene ether)s, P1 and P2, containing perfluorophenyl moieties in the main chains and second-order nonlinear optical (NLO) chromophores in the side chains have been conveniently prepared by Knoevenagel condensation reaction between perfluorophenyl-containing poly-(arylene ether) P and cyanoacetylated NLO chromophores 2 and 3 for the first time. The molar percentages of the pendant chromophores were estimated to be 162% and 138% for P1 and P2, respectively, and their weight percentages were both 42.3%. Both of the two polymers are thermally stable and readily soluble in common organic solvents. The glass transition temperatures (T_g's) of P1 and P2 were determined to be 186 and 192°C, respectively. The in-situ second harmonic generation (SHG) measurement revealed the resonant NLO coefficient (d ₃₃) values of 60 and 31 pm/V for the poled films of PI and P2, respectively. The thermal stability of the SHG signals of the polymer films was studied by the depoling experiment in air using PI as the typical polymer, in which the decay onset of the SHG signal occurred at around 160°C.

Full text of DOI:10.1021/ma048889h

Macromolecules 2004, 37, 7089-7096
7089
Articles
Two Novel Fluorinated Poly(arylene ether)s with Pendant
Chromophores for Second-Order Nonlinear Optical Application
Zh a oqia n g Lu ,† P in Sh a o,† J u n Li,† J ia n li Hu a ,† J in gu i Qin ,*,† An ju n Qin ,‡ a n d
Ch en g Ye*,‡
Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China, and Institute of Chemistry,
Chinese Academy of Science, Beijing 100080, P. R. China
Received J une 6, 2004; Revised Manuscript Received J uly 11, 2004
ABSTRACT: Two fluorinated poly(arylene ether)s, P 1 and P 2, containing perfluorophenyl moieties in
the main chains and second-order nonlinear optical (NLO) chromophores in the side chains have been
conveniently prepared by Knoevenagel condensation reaction between perfluorophenyl-containing poly-
(arylene ether) P and cyanoacetylated NLO chromophores 2 and 3 for the first time. The molar percentages
of the pendant chromophores were estimated to be 162% and 138% for P 1 and P 2, respectively, and
their weight percentages were both 42.3%. Both of the two polymers are thermally stable and readily
soluble in common organic solvents. The glass transition temperatures (Tg’s) of P 1 and P 2 were determined
to be 186 and 192 °C, respectively. The in-situ second harmonic generation (SHG) measurement revealed
the resonant NLO coefficient (d33) values of 60 and 31 pm/V for the poled films of P 1 and P 2, respectively.
The thermal stability of the SHG signals of the polymer films was studied by the depoling experiment in
air using P 1 as the typical polymer, in which the decay onset of the SHG signal occurred at around 160
°C.
In tr od u ction
glass transition temperatures (Tg’s), such as polyim-
ides22 and polyquinolines,23 have been employed as
excellent NLO polymers. Lately, J en et al. also intro-
duced fluorinated moieties into NLO active dendrim-
ers24,25 and dendronized polymers,5,26,27 and they found
that the fluorinated moieties could also bring many
outstanding properties, such as low optical loss, low
birefringence, good processability, and high thermal
stability to these materials, and retain their extraordi-
narily large macroscopic NLO activities simultaneously.
All of the above studies have demonstrated that the
fluorinated polymeric materials may fulfill many of the
requirements of the NLO materials.
Considerable effort has been devoted to the develop-
ment of organic nonlinear optical (NLO) polymeric
materials since two decades ago due to their potential
photonics applications and many advantages over single
crystals.1-3 Recently, the new discoveries by Dalton4 and
J en5 of the enhancement of NLO activities of the
polymers and the minimization of the halfwave voltage
of electrooptic (E-O) modulators reattracted much new
attention to them. For practical applications, the device-
quality NLO polymers must retain high optical quality
thin films, high optical damage thresholds, low optical
propagation loss, and feasibility of device fabrication,
besides the sufficiently large and stable NLO suscepti-
bilities.3,6 Although it is extremely difficult to solve all
the problems, they have been ameliorated by different
research groups.7-10 Fluorinated polymers are of grow-
ing interest in the investigation of NLO materials in
recent years.11-15 Their unique properties16-21 including
low dielectric constant, refractive index, optical loss and
moisture absorption, high thermal and chemical stabil-
ity, and good processability are all necessary for NLO
applications. Furthermore, the fluorinated moieties can
improve the properties of the NLO polymeric materials
without weakening their NLO activities.10-15,21,22 Thus,
many fluorinated polymers, especially those with high
On the other hand, fluorinated poly(arylene ether)s
containing perfluorophenyl moieties in the polymer
backbones have been evaluated for optical waveguide
components in recent years because they enable the
balance of the properties such as birefringence, Tg, and
adhesion by adjusting the structures and fluorine
contents.16,28-31 In addition, the perfluorophenyl moi-
eties give the polymers good thermal stability and
mechanical properties similar to those of polyimides,
while the flexibilizing ether groups make them exhibit
better solubility than polyimides.29,32,33 So they are more
accessible for optical utilization.
In this paper, two fluorinated poly(arylene ether)s P 1
and P 2 containing perfluorophenyl moieties in the
backbones and NLO chromophores in the side chains
were successfully prepared for NLO application. Thus,
a fluorinated poly(arylene ether) P with aldehyde
groups in the side chains was first prepared by the
nucleophilic aromatic substitution polycondensation
† Wuhan University.
‡ Chinese Academy of Science.
* To whom correspondence should be addressed. J ingui Qin: Tel
+86-27-87684117, Fax +86-27-87686757, e-mail jgqin@whu.edu.cn.
Cheng Ye: Tel +86-10-62588928, e-mail yec@iccac.ac.cn.
10.1021/ma048889h CCC: $27.50 © 2004 American Chemical Society
Published on Web 08/25/2004

7090 Lu et al.
Macromolecules, Vol. 37, No. 19, 2004
Sch em e 1. Syn th etic Rou te to P , P 1, a n d P 2
reaction between perfluorobiphenyl and double aldehyde
groups containing bisphenol 1, and then the cyanoacety-
lated NLO chromophores 2 and 3 were attached to P
as pendant groups by Knoevenagel condensation reac-
tion under mild conditions (Scheme 1). To the best of
our knowledge, P 1 and P 2 are the first two examples
of fluorinated poly(arylene ether)s for NLO applications.
In addition, the postfunctionalization reaction condition
in this study is mild enough to tolerate other sensitive
high µâ chromophores, which can also be conveniently
introduced into P as pendant groups by this synthetic
route. We hope that this study can promote much
research interest to the fluorinated poly(arylene ether)s
for NLO applications.
In the IR spectrum of P , the absorption bands at 1225
and 1693 cm-1 were attributed to the stretching vibra-
tion of the aromatic ether group and the carbonyl of the
aromatic aldehyde group, respectively, which confirmed
the formation of P . In the IR spectra of P 1 and P 2, the
absorption band at 1225 cm-1 exhibited no significant
change, while the absorption band at 1693 cm-1 was
weakened significantly, and two new absorption bands
at 1734 and 2220 cm-1 appeared, contributed by the
carbonyl stretching vibration of the conjugated carboxy-
lic esters and the nitrile stretching vibration. In addi-
Resu lts a n d Discu ssion
Syn th esis. The synthetic route to P , P 1, and P 2 is
shown in Scheme 1. To introduce the perfluorophenyl
moieties and the NLO chromophores, a very active
monomer, perfluorobiphenyl, first reacted with a double
aldehyde group containing bisphenol 1 under the nu-
cleophilic aromatic substitution polycondensation condi-
tion to afford fluorinated poly(arylene ether) P with
pendant aldehyde groups. Knoevenagel condensation
reaction was chosen as the postfunctionalization reac-
tion to synthesize P 1 and P 2 due to its mild synthetic
conditions and the high reactivity of the aldehyde
groups toward this reaction, and the cyanoacetates were
selected as the active hydrogen species because of their
high reactivity and minimized byproduct in this reac-
tion.34 In this study, pyridine was utilized as the solvent
instead of dimethylformamide (DMF) which had ever
been used by our group in Knoevenagel condensation
reaction to prepare a NLO chromophore functionalized
poly(N-vinylcarbazole) (PVK).35 As a result, we found
that in this reaction pyridine was more favorable than
DMF, in which the reaction time was shortened from
48 h (in DMF35) to only 6 h. Furthermore, the high
molar percentages of the chromophores of P 1 and P 2
also demonstrated that this synthetic method was very
effective.
St r u ct u r a l Ch a r a ct er iza t ion of P , P 1, a n d P 2.
The IR spectra of P , P 1 and P 2 are shown in Figure 1.
F igu r e 1. IR spectra of P , P 1, and P 2.

Macromolecules, Vol. 37, No. 19, 2004
NLO Active Fluorinated Poly(arylene ether)s 7091
F igu r e 2. 1H NMR spectra of P , P 1, and P 2 (in CDCl3, with TMS as a reference; *, solvent; #, water).
1
tion, a new absorption band at 1339 cm-1 emerged in
the IR spectrum of P 1, contributed by the nitro stretch-
ing vibration of chromophore 2. The above results
confirmed that cyanoacetylated chromophores 2 and 3
were successfully introduced into the side chains of the
polymers.
bisphenol 1. While in the H NMR spectra of P 1 and
P 2, some new peaks appeared distinctly. These new
peaks were in good agreement with the chemical shifts
of the protons of the chromophores 2 and 3, respectively.
From the comparison of the integration of the methylene
in the backbones and the aldehyde groups in the side
chains in the H NMR spectra of P 1 and P 2, the molar
ratios of the double-substituted, monosubstituted, and
nonsubstituted aldehyde groups were estimated to be
1
1
Figure 2 exhibits the H NMR spectra of P , P 1, and
P 2. In the 1H NMR spectrum of P , all of the peaks
accorded with the chemical shifts of the protons of

7092 Lu et al.
Macromolecules, Vol. 37, No. 19, 2004
F igu r e 3. 19F NMR spectra of P , P 1, and P 2 (in CDCl3, with CF3COOH as a reference).
0.625:0.370:0.005 and 0.39:0.60:0.01 for P 1 and P 2,
respectively. Thus, the molar percentages of the chro-
mophores were calculated to be 162% and 138% for P 1
and P 2, respectively, and the weight percentages of the
chromophores were calculated to be 42.3% for both P 1
and P 2. These percentages of the chromophores were
consistent with the results of elemental analysis.
19F NMR study was also conducted using trifluoro-
acetic acid (CF3COOH) as a reference to confirm the
structures of P , P 1, and P 2, which are presented in
Figure 3. In the nucleophilic substitution reactions,
perfluorobiphenyl is very active, and the reactions
usually take place at 4,4′-sites of perfluorobiphenyl first;
however, the fluorines at other sites will also react
under appropriate conditions and produce cross-linking
products.36 In the 19F NMR spectrum of P , only two
peaks at the chemical shifts of -137.34 and -152.87
ppm appeared, attributed to the fluorines meta and

Macromolecules, Vol. 37, No. 19, 2004
NLO Active Fluorinated Poly(arylene ether)s 7093
F igu r e 4. UV-vis spectra of P , P 1, and P 2 (in THF).
ortho to the ether linkage, respectively. This result
demonstrated that the nucleophilic substitution reaction
only took place at 4,4′-sites of perfluorobiphenyl under
our polymerization conditions. After being functional-
ized with cyanoacetylated chromophores 2 and 3, these
two peaks exhibited no significant changes in the 19F
NMR spectra of P 1 and P 2, which indicated that there
were no changes of the perfluorophenyl moiety in the
polymer backbones in Knoevenagel condensation reac-
tion. In addition, three new peaks at the chemical shifts
of -152.23, -153.70, and -163.67 ppm emerged dis-
tinctively in the 19F NMR spectrum of P 2. These new
peaks were in good agreement with the chemical shifts
of the fluorines in chromophore 3, which confirmed the
successful attachment of the chromophores to P as the
pendent groups.
F igu r e 5. UV-vis spectra of the films of P 1 and P 2 before
and after poling.
could be seen from the spectra that, after poling, the
absorbance bands with the λmax at about 473 and 445
nm for P 1 and P 2, corresponding to the intramolecular
charge transfer of chromophore 2 and 3, decreased
significantly. The order parameters (Φ)37 of the poled
films (Φ ) 1 - A1/A0, where A0 and A1 are the maximum
absorbance before and after poling, respectively) were
calculated to be 0.14 and 0.18 for P 1 and P 2, respec-
tively. Calculation of the resonant NLO coefficient (d33
)
values for the poled films of P 1 and P 2 was based upon
the following equation:38
d33,s
d11,q
Is Ic,q
Perfluorophenyl moieties make P , P 1, and P 2 exhibit
excellent solubility. At room temperature, they are
readily soluble in common organic solvents, such as
chloroform, methylene dichloride, tetrahydrofuran (THF),
pyridine, m-cresol, cyclopentanone, dimethyl sulfoxide
(DMSO), dimethylformamide (DMF), N-methylpyrroli-
done (NMP), etc. Figure 4 shows the UV-vis spectra of
P , P 1, and P 2 in the solution of THF. After Knoevenagel
condensation reaction, a new strong absorption maxima
(λmax) corresponding to the intramolecular charge trans-
fer of chromophore 2 at about 473 nm appeared in the
UV-vis spectrum of P 1, while that of chromophore 3
at about 432 nm emerged in the UV-vis spectrum of
P 2. Compared with the λmax of P 1, the λmax of P 2 was
blue-shifted about 41 nm due to the enhancement of the
transparency of chromophore 3 by the perfluorophenyl
moiety.
Gel permeation chromatography with multiangle
static light scattering (GPC-MASLS) measurement in
THF indicated that the absolute weight-average molec-
ular weights (Mw) of P , P 1, and P 2 were 48 700,
212 700, and 248 500, respectively, with the polydis-
persities (Mw/Mn) of 2.31, 3.22, and 2.68, respectively.
Perfluorophenyl moieties also give excellent thermal
properties to P , P 1, and P 2. Observed from DSC
experiments, the Tg’s of P , P 1, and P 2 were 198, 186,
and 192 °C, respectively. The TGA thermograms of P ,
P 1, and P 2 indicated that their 5% weight loss tem-
peratures were all above 260 °C in both air and argon.
NLO P r op er ties of P 1 a n d P 2. To evaluate the
NLO activities of P 1 and P 2, uniform and transparent
thin films of these two polymers were prepared by spin-
coating their cyclopentanone solution onto ITO sub-
strates for second harmonic generation (SHG) measure-
ments. The noncentrosymmetric alignment of the
chromophores, which was essential for second-order
optical nonlinearity, was achieved by corona poling, and
the optimum poling temperatures for the films of P 1
and P 2 in the SHG measurements were 170-180 and
150-160 °C, respectively. Figure 5 shows the UV-vis
spectra of the polymer films before and after poling. It
)
F
I
Is
x
q
where the d11,q was d11 of the quartz crystals, which was
0.45 pm/V, Is and Iq were the SHG intensities of the
sample and the quartz, respectively, lc,q was the coher-
ent length of the quartz, ls was the thickness of the
polymer films, and F was the correction factor of the
apparatus and equaled 1.2 when lc . ls. The d33 values
of the poled films of P 1 and P 2 were calculated to be
60 and 31 pm/V, respectively, at 1064 nm fundamental
wavelength, and the nonresonant NLO coefficient (d33
-
(∞)) values were estimated to be 10 and 8 pm/V for P 1
and P 2, respectively, by using the approximate two-level
model.39 Yu et al.40 have reported a series of polyimides
containing chromophore 2 with very high d33 values of
59, 69, and 169 pm/V (the relevant d33(∞) values were
7, 9, and 18 pm/V). To the best our knowledge, the d33
value of 169 pm/V is the highest one so far among the
d33 values of the polymers containing 2 as the NLO
chromophore. On the other hand, until now, there is
only one paper41 reporting the d33 value of 11.5 pm/V
for the polymer containing 3 as the NLO chromophore.
Compared with the above results, the d33 and d33(∞)
values of P 1 and P 2 were relatively high.
The dynamic thermal stability of the SHG signals of
the poled polymer films was investigated through de-
poling experiment in which the real-time decay of the
SHG signals was monitored when the poled films were
heated at a rate of 4-5 °C/min in the range 20-200 °C
in air. P 1 was selected as the typical polymer, and its
plot of d33(t)/d33(0) vs temperature is shown in Figure
6. It can be seen that the decay onset of the SHG signal
occurred at around 160 °C, and its half-decay temper-
ature of the SHG signals was at about 180 °C. Progresses
in identifying the NLO chromophores with large hyper-
polarizabilities, high thermal stability, and low optical
loss have already taken place.1,42-47 These chromophores
could be exploited with the fluorinated poly(arylene
ether)s considered here to prepare more excellent

7094 Lu et al.
Macromolecules, Vol. 37, No. 19, 2004
gas flow of 20 mL/min. Thermogravimetric analysis (TGA) was
performed with a Shimadzu-DT 40 instrument at a heating
rate of 20 °C/min under static air and argon with gas flow of
50 mL/min. The molecular weights were determined by gel
permeation chromatography with multiangle static light scat-
tering (GPC-MASLS). GPC-MALLS measurements were per-
formed on a DAWN DSP multiangle laser photometer with a
pump P100 (Thermo Separation Products, San J ose, CA)
equipped with a TSK-GEL G4000 HHR and a differential
refractive index detector (RI-150) at 25 °C. The eluent was
THF, and its flow rate was 1.00 mL/min. All solutions were
filtered with sand filter and 0.45 µm filter (PTFE, Puradisc
13 mm Syringe Filters, Whattman, England). Astra software
was utilized for data acquisition and analysis. The thickness
of the poled films of the polymers was determined by a
Talysurf-S4C surface profiler.
Ch r om op h or e Syn t h esis. Syn t h esis of N-E t h yl-N-(2-
h ydr oxyeth yl)-4-(pen taflu or oph en ylazo)an ilin e. This new
chromophore was prepared from N-ethyl-N-(2-hydroxyethyl)-
aniline and pentafluoroaniline in a similar way reported in
the literature.49 After recrystallization from toluene/petroleum
(60-90 °C), pure product was obtained as an orange crystalline
F igu r e 6. Decay of the SHG coefficient signals as a function
of temperature for P 1.
1
solid; yield 53%. H NMR (CDCl3, TMS int) δ (ppm): 1.23 (t,
candidates for electrooptic (E-O) applications in the
future.
J ) 7.2 Hz, 3H, -CH3), 3.73 (q, 4H, -NCH2), 4.41 (t, J ) 7.2
Hz, 2H, -CH2OH), 6.69 (d, J ) 9.0 Hz, 2H, ArH), 7.51 (d, J )
9.0, 2H, ArH).
Con clu sion s
Syn th esis of Cya n oa cetyla ted N-Eth yl-N-(2-h yd r oxy-
eth yl)-4-(p en ta flu or o-p h en yla zo)a n ilin e (3). Chromophore
3 was prepared from the above new chromophore and cy-
anoacetic acid in a similar way reported in the literature.35
The crude product was purified by column chromatography
using chloroform/ethyl acetate (6/1, v/v), and pure chromophore
3 was obtained as an orange powder; yield 78%, mp 93-94
°C. FT-IR (KBr pellet, cm-1): 2262 (νCN), 1745 (νCdO). 1H NMR
(CDCl3, TMS int) δ (ppm): 1.25 (t, J ) 7.2 Hz, 3H, -CH3),
3.47 (s, 2H, CNCH2COO-), 3.75 (q, J ) 7.0 Hz, 2H, -NCH2-
CH3), 4.43 (t, 2H, -COOCH2-), 6.78 (d, J ) 9.0 Hz, 2H, ArH),
7.86 (d, J ) 9.0 Hz, 2H, ArH). MS (FAB), m/z [M+]: 426. Calcd
for C19H15N4O2F5: C, 53.52; H, 3.52; N, 13.14. Found: C, 53.45;
H, 3.47; N, 13.15.
The first two examples of NLO active fluorinated poly-
(arylene ether)s P 1 and P 2 have been conveniently
prepared under mild postfunctionalization reaction
condition in this study. The molar percentages of the
chromophores are 162% and 138% for P 1 and P 2,
respectively, and their weight percentages are both
42.3%. The introduction of the perfluorophenyl moieties
provides the polymers with excellent solubility and good
thermal properties. SHG measurement indicated that
the resonant NLO coefficient (d33) values of P 1 and P 2
were 60 and 31 pm/V, respectively, and the nonresonant
NLO coefficient (d33(∞)) values were respectively esti-
mated to be 10 and 8 pm/V for P 1 and P 2. P 1 and P 2
exhibit high Tg’s (186 °C for P 1 and 192 °C for P 2), and
the SHG signal of the typical polymer P 1 was thermally
stable below 160 °C after poling. These two polymers
represent a promising NLO polymeric system.
P olym er Syn th esis. Syn th esis of P . A dry, 50 mL three-
necked flask equipped with an oil bath, a mechanical stirrer,
a Dean-Stark trap, a cold water condenser, an argon inlet/
outlet, and a thermometer was charged with 3 (0.2563 g, 1
mmol), anhydrous potassium carbonate (0.1935 g, 1.4 mmol),
5 mL of N,N-dimethylacetamide (DMAc), and 10 mL of
toluene. The reaction mixture was heated under an argon
atmosphere at 130-140 °C to remove the water by means of
azotropic distillation with toluene. After about 3 h, all the
water was removed and toluene was distilled. Then, the
solution was cooled to room temperature, and perfluorobiphen-
yl (0.3341 g, 1 mmol) was added into the flask. The solution
was then heated to 165-170 °C and stirred vigorously at this
temperature until a very viscous solution was obtained. After
cooling to room temperature, 3 mL of DMAc was added into
the solution, which was then poured into 200 mL of methanol
containing a few drops of glacial acetic acid to precipitate the
polymer. The precipitate was collected, dried, and dissolved
in chloroform, filtered to remove insoluble solid, and repre-
cipitated by adding the solution dropwise into methanol. After
being dissolved/precipitated from chloroform/methanol twice
and dried in vacuo at 60 °C overnight, 0.38 g of white fibrous
Exp er im en ta l Section
Mater ials. Perfluorobiphenyl, pentafluoroaniline, and 4-(N,N-
dimethylamino)pyridine (DMAP) were purchased from Acros
and used as received. Cyanoacetic acid and 1,3,5-trioxane were
purchased from Fluka and used as received. 1,3-Dicyclohexyl-
carbodiimide (DCC) and 2-hydroxybenzaldehyde were distilled
under reduced pressure before use. Pyridine, piperidine,
tetrahydrofuran (THF), and cyclopentanone were dried and
distilled over potassium hydroxide (KOH), calcium hydride
(CaH2), sodium, and pentaphosphine oxide (P2O5), respectively,
before use. 5,5′-Methylenebis(salicylaldehyde) (1) was prepared
from 1,3,5-trioxane and 2-hydroxybenzaldehyde according to
the method of the literature48 and recrystallized twice from
acetone before use. Cyanoacetylated dispersed red 1 (DR-1)
(2) was prepared from DR-1 and cyanoacetic acid following the
method in the literature.35 Other chemicals were used as
received without further purification.
1
solid was obtained; yield 69.1%. H NMR (CDCl3, TMS int) δ
(ppm): 4.04 (s, 2H, -CH2-), 6.83 (d, 2H, ArH), 7.35 (d, 2H,
ArH), 7.77 (s, 2H, ArH), 10.57 (s, 1H, -CHO). 19F NMR (CDCl3,
CF3COOH int) δ (ppm): -137.34, -152.87.
Mea su r em en ts. 1H NMR and 19F NMR spectra were
recorded on a Varian-Mercury VX300 spectrophotometer using
chloroform-d (CDCl3) as a solvent and tetramethylsilane (TMS)
(1H) or trifluoroacetic acid (CF3COOH) (19F) as a reference. The
IR spectra were recorded on a NICOLET 170SKFT-IR spec-
Syn th esis of P 1. A dry, 20 mL two-necked flask equipped
with an oil bath, a magnetic stirrer, a cold water condenser,
and an argon inlet/outlet was charged with P (0.2 g, 0.364
mmol), chromophore 2 (0.28 g, 0.727 mmol), 15 mL of pyridine,
and piperidine (10 µL). After the reaction mixture was dis-
solved, the solution was heated to 55-60 °C for 6 h under an
argon atmosphere. Then the solution was cooled to room
temperature and poured into 400 mL of methanol to precipi-
tate the polymer. The polymer was collected by filtration and
trophotometer with KBr pellets in the region 4000-400 cm-1
.
Elemental analysis (EA) was performed on
a Calo-Erba
elemental analyzer (model 1106). The FAB-MS spectrum was
conducted with a VJ -ZAB-3F mass spectrometer. Differential
scanning calorimetry (DSC) was performed with a Pyris 1 DSC
instrument under nitrogen at a heating rate of 15 °C/min with

Macromolecules, Vol. 37, No. 19, 2004
NLO Active Fluorinated Poly(arylene ether)s 7095
Ta ble 1. P er cen ta ges of Ch r om op h or es a n d Com p osition s of P 1 a n d P 2
elemental analysis [%]: found (calcd)
a
b
polymer
x
y
z
dm (%)
dw (%)
C
H
N
P 1
P 2
0.625
0.39
0.37
0.60
0.005
0.01
162
138
42.3
42.3
61.26 (60.93)
56.89 (57.28)
3.32 (3.33)
3.06 (2.72)
9.25 (9.96)
6.15 (6.93)
a
b
Molar percentages of the chromophores. Weight percentages of the chromophores.
Ta ble 2. Molecu la r Weigh ts a n d Th er m a l P r op er ties of P ,
P 1 a n d P 2
crystal served as a reference. The NLO coefficients d33 were
deduced by comparing the intensities of the SHG signals of
the poled film with those of the quartz crystal.
Td (°C)
a
Mw
polydispersity
polymer (×104)
(Mw/Mn)
Tg (°C) in airc in argond
b
Ack n ow led gm en t. We are grateful to the National
Key Fundamental Research Program of China and the
National Science Foundation of China for the financial
support.
P
P 1
P 2
4.87
21.27
24.85
2.31
3.22
2.68
198
186
192
347
288
263
347
291
269
a
Molecular weights were determined by GPC-MASLS at 25 °C
b
with THF as the eluent. Tg’s were determined by DSC at a
heating rate of 15 °C/min under nitrogen with a gas flow of 20
mL/min. c 5% weight loss temperatures were detected at a heating
Refer en ces a n d Notes
(1) Marder, S. R.; Kippelen, B.; J en, A. K.-Y.; Peyghambarian,
N. Nature (London) 1997, 388, 845.
d
rate of 20 °C/min under static air. 5% weight loss temperatures
were detected at a heating rate of 20 °C/min under argon with a
gas flow of 50 mL/min.
(2) Moerner, W. E.; J epsen, A. G.; Thompson, C. L. Annu. Rev.
Mater. Sci. 1997, 32, 585.
(3) Burland, D. M.; Miller, R. D.; Walsh, C. A. Chem. Rev. 1994,
94, 31.
Ta ble 3. NLO P r op er ties of P 1 a n d P 2
(4) Shi, Y.; Zhang, C.; Zhang, H.; Bechtel, J . H.; Dalton, L. R.;
Robinson, B. H.; Steier, W. H. Science 2000, 288, 119.
(5) Luo, J .; Liu, S.; Haller, M.; Liu, L.; Ma, H.; J en, A. K.-Y. Adv.
Mater. 2002, 14, 1763.
a
b
d
polymer Topt (°C) ls (µm) Φc d33 (pm/V) d33(∞)e (pm/V)
P 1
P 2
170-180
150-160
0.44
0.72
0.14
0.18
60
31
10
8
(6) Marks, T. J .; Ratner, M. A. Angew. Chem., Int. Ed. Engl.
Optimal poling temperatures of the polymer films. b Thickness
a
1995, 34, 155.
of the polymer films. c Order parameters of the poled films.
(7) Zhang, C.; Wang, C.; Dalton, L. R.; Zhang, H.; Steier, W. H.
Macromolecules 2001, 34, 253.
(8) Ma, H.; Wu, J .; Herguth, P.; Chen, B.; J en, A. K.-Y. Chem.
d
Resonant NLO coefficient values determined by SHG measure-
ments. e Nonresonant NLO coefficient values estimated by the
approximate two-level model.
Mater. 2000, 12, 1187.
(9) Li, Z.; Qin, J .; Li, S.; Ye, C.; Luo, J .; Cao, Y. Macromolecules
2002, 35, 9232.
(10) Taylor, D. K.; Samulski, E. T. Macromolecules 2000, 33, 2355.
(11) Ma, H.; Wu, J .; Herguth, P.; Chen, B.; J en, A. K.-Y. Chem.
Mater. 2000, 12, 1187.
purified by being dissolved/precipitated from chloroform/
methanol twice. After being dried in vacuo at 60 °C overnight,
0.29 g of red fibrous solid was obtained; yield 61.7%. 1H NMR
(CDCl3, TMS int) δ (ppm): 1.25 (m, 3H, -CH3), 3.55 (m, 2H,
-NCH2CH3), 3.80 (m, 2H, -NCH2CH2-), 4.03 (m, 2H, -CH2-),
4.53 (m, 2H, -NCH2CH2-), 6.79 (m, 4H, ArH), 7.37 (m, 2H,
ArH), 7.83 (m, 4H, ArH), 8.23 (m, 4H, ArH), 8.76 (s, 1H, -CH
) C(CN)-), 10.56 (s, 1H, -CHO). 19F NMR (CDCl3, CF3COOH
int) δ (ppm): -137.08, -152.55.
P 2 was prepared in the similar way of P 1 and was obtained
as an orange fibrous solid; yield 86.3%. 1H NMR (CDCl3, TMS
int) δ (ppm): 1.19 (m, 3H, -CH3), 3.50 (m, 2H, -NCH2CH3),
3.73 (m, 2H, -NCH2CH2-), 4.45 (m, 2H, -CH2-), 6.72 (m,
4H, ArH), 7.33 (m, 2H, ArH), 7.74 (m, 4H, ArH), 8.70 (s, 1H,
-CHdC(CN)-), 10.50 (s, 1H, -CHO). 19F NMR (CDCl3, CF3-
COOH int) δ (ppm): -137.28, -152.23, -152.78, -153.70,
-163.67.
P olym er F ilm P r ep a r a tion . P 1 and P 2 were dissolved
in cyclopentanone, and the solution (10 wt %) was filtered
through syringe filters. Polymer films were obtained by spin-
coating the polymer solution onto indium tin oxide (ITO)-
coated glass substrates (which were cleaned in the ultrasonic
bath with DMF, THF, ethanol, and distilled water subse-
quently). The residual solvent was removed by heating the
films in a vacuum oven at 70 °C for 3 days. The thickness of
the films of P 1 and P 2 was estimated to be 0.44 and 0.72 µm,
respectively, as listed in Table 3.
Ch a r a cter iza tion of P oled F ilm s. The second-order opti-
cal nonlinearities of P 1 and P 2 were determined by the in-
situ second-harmonic generation (SHG) measurement tech-
nique. Thus, a closed temperature-controlled oven having
optical windows and equipped with three needle electrodes was
used. The films, which were kept at 45 ° to the incident beam,
were poled inside the oven, and the SHG intensity was
monitored simultaneously. The poling condition was as fol-
lows: voltage, 7.6 kV at the needle point; gap distance, 0.8
cm. The SHG measurements were carried out with a Nd:YAG
laser operating with a 10 Hz repetition rate and an 8 ns pulse
width at 1064 nm fundemental wavelength. A Y-cut quartz
(12) Mcculloch, I.; Yoon, H. J . Polym. Sci., Part A: Polym. Chem.
1995, 33, 1177.
(13) Verbiest, T.; Burland, D. M.; J urich, M. C.; Lee, V. Y.; Miller,
R. D.; Volksen, W. Science 1995, 268, 1604.
(14) Zhang, C.; Wang, C.; Zhou, C.; Lee, M.; Chen, M.; Dalton, L.
R. Polym. Prepr. 1999, 40, 912.
(15) Ma, H.; Wang, X.; Wu, X.; Liu, S.; J en, A. K.-Y. Macromol-
ecules 1998, 31, 4049.
(16) Ma, H.; J en, A. K.-Y.; Dalton, L. R. Adv. Mater. 2002, 14,
1339.
(17) Goodwin, A. A.; Mercer, F. W.; McKenzie, M. T. Macromol-
ecules 1997, 30, 2767.
(18) Nagal, J . K. J . Am. Chem. Soc. 1990, 112, 4740.
(19) Hudliky, M. Chemistry of Organic Fluorine Compounds, 2nd
ed.; Ellis Horwood: Chichester, 1992; p 531.
(20) Lu, J .; Miyatake, K.; Hill, A. R.; Hay, A. S. Macromolecules
2001, 34, 5860.
(21) Miyatake, K.; Hay, A. S. J . Polym. Sci., Part A: Polym. Chem.
2001, 39, 3770.
(22) Do, J . Y.; Park, S. K.; Park, S.; J u, J .-J .; Lee, M.-H. Polym.
Prepr. 2003, 44 (1), 821.
(23) Ma, H.; Wang, X.; Qu, X.; Liu, S.; J en, A. K.-Y. Macromol-
ecules 1998, 31, 4049.
(24) Ma, H.; Chen, B.; Sassa, T.; Dalton, L. R.; J en, A. K.-Y. J .
Am. Chem. Soc. 2001, 123, 986.
(25) Ma, H.; Liu, S.; Luo, J .; Suresh, S.; Liu, L.; Kang, S. H.;
Haller, M.; Sassa, T.; Dalton, L. R.; J en, A. K.-Y. Adv. Funct.
Mater. 2002, 12, 565.
(26) Luo, J .; Haller, M.; Li, H.; Tang, H.-Z.; J en, A. K.-Y.; J akka,
K.; Chou, C.-H.; Shu, C.-F. Macromolecules 2004, 37, 248.
(27) Luo, J .; Haller, M.; Li, H.; Kim, T.-D.; J en, A. K.-Y. Adv.
Mater. 2003, 15, 1635.
(28) Lee, H.-J .; Lee, E.-M.; Lee, M.-H.; Oh, M.-C.; Ahn, J .-H.; Han,
S. G.; Kim, H. G. J . Polym. Sci., Part A: Polym. Chem. 1998,
36, 2881.
(29) Lee, H.-J .; Lee, M.-H.; Oh, M.-C.; Ahn, J .-H.; Han, S. G. J .
Polym. Sci., Part A: Polym. Chem. 1999, 37, 2355.
(30) Kim, J .-P.; Lee, W.-Y.; Kang, J .-W.; Kwon, S.-K.; Kim, J .-J .;
Lee, J .-S. Macromolecules 2001, 34, 7817.

7096 Lu et al.
Macromolecules, Vol. 37, No. 19, 2004
(31) Pitois, C.; Wiesmann, D.; Lindgren, M.; Hult, A. Adv. Mater.
2001, 13, 1483.
(41) Hua, J .; Luo, J .; Long, K.; Qin, J .; Li, S.; Ye, C.; Lu, Z. Eur.
Polym. J . 2004, 40, 1193.
(32) Hendricks, N. H.; Lau, K. S. Y. Polym. Prepr. 1996, 37 (1),
150.
(33) Miyatake, K.; Hay, A. S. J . Polym. Sci., Part A: Polym. Chem.
2001, 39, 3211.
(42) Marder, S. R.; Perry, J . W.; Bourhill, G.; Gorman, C. B.;
Tiemann, B. G.; Mansour, K. Science 1993, 261, 186.
(43) Luo, J .; Hua, J .; Qin, J .; Cheng, J .; Shen, Y.; Lu, Z.; Wang,
P.; Ye, C. Chem. Commun. 2001, 171.
(34) Tietze, L. F.; Beifuss, U. The Knoevenagel Condensation. In
Comprehensive Organic Synthesis; Trost, B. M., Fleming, I.,
Eds.; Pergamon Press: Oxford, England, 1991; Vol. 2, p 341.
(35) Luo, J .; Qin, J .; Kang, H.; Ye, C. Chem. Mater. 2001, 13, 927.
(36) Lu, Z.; Cheng, L.; Li, J .; Zhang, K.; Yi, S.; Qin, J . J . Polym.
Sci., Part A: Polym. Chem. 2004, 42, 925.
(37) Mortazavi, M. A.; Knoesen, A.; Kowel, S. T.; Higgins, B. G.;
Dienes, A. J . Opt. Soc. Am. B 1989, 6, 733.
(38) Dalton, L. R.; Xu, C.; Harper, A. W.; Ghosn, R.; Wu, B.; Liang,
Z.; Montgomery, R.; J en, A. K.-Y. Nonlinear Opt. 1995, 10,
383.
(44) Luo, J . D.; Ma, H.; Haller, M.; J en, A. K.-Y.; Barto, R. R.
Chem. Commun. 2002, 888.
(45) He, M.; Leslie, T. M.; Sinicropi, J . A. Chem. Mater. 2002, 14,
2393.
(46) Liu, S.; Haller, M.; Ma, H.; Dalton, L. R.; J ang, S.-H.; J en,
A. K.-Y. Adv. Mater. 2003, 15, 603.
(47) Moylan, C. R.; Twieg, R. J .; Lee, V. Y.; Swanson, S. A.;
Betterton, K. M.; Miller, R. D. J . Am. Chem. Soc. 1993, 115,
12599.
(48) Marvel, C. S.; Tarkoy, N. J . Am. Chem. Soc. 1957, 79, 6000.
(49) Brooke, G. M.; Forbes, E. J .; Richardson, R. D.; Stacey, M.;
Tatlow, J . C. J . Chem. Soc. 1965, 2088.
(39) Kauranen, M.; Verbiest, T.; Boutton, C.; Teeren, M. N.; Clay,
K.; Schouten, A. J .; Nolte, R. J . M.; Persoons, A. Science 1995,
270, 966.
(40) Yu, D.; Gharavi, A.; Yu, L. J . Am. Chem. Soc. 1995, 117,
11680.
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