facile fabrication of electrochromic poly(amineamide) and...

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Full PaperMacromolecularChemistry and Physics

wileyonlinelibrary.com DOI: 10.1002/macp.201400171

Facile Fabrication of Electrochromic Poly(amine-amide) and Poly(amine-imide) Films Via Carbazole-Based Oxidative Coupling Electropolymerization

Sheng-Huei Hsiao , * Jun-Wen Lin

The synthesis and electrochemical properties of four electropolymerizable monomers featuring an interior aromatic diamide or diimide segment bridged by p -phenylene units to terminal electroactive carbazole groups are described. Upon electrochemical oxidation, the coupling reactions between carbazole radical cations occur instantly, rendering an effi cient electropo-lymerization process feasible. The electrogenerated polymer fi lms exhibit reversible electrochemical processes and stable color changes upon electro-oxidation, which can be switched by potential modulation. The remarkable electrochromic behavior of the fi lm is clearly interpreted on the basis of spectroelectrochemical studies.

Prof. S.-H. Hsiao, J.-W. Lin Department of Chemical Engineering and Biotechnology , National Taipei University of Technology , Taipei , Taiwan E-mail: [email protected]

in the Reynolds group has been focused on the under-standing and the tailoring of electrochromic properties in conjugated polymers such as poly(3,4-alkylenedioxythio-phene)s (PEDOT) [ 6 ] and poly(3,4-alkylenedioxypyrrole)s (PEDOP). [ 7 ] Many other conjugated polymer systems exhib-iting attractive electrochromic performance have also been explored by other research groups. [ 8 ] The electroactive and conjugated polymers generally demonstrated superior electrochromic properties, such as a fast switching cap-ability, high contrast ratio, high coloration effi ciency (CE), and good long-term stability. These conjugated polymers can be synthesized by either chemical or electrochemical polymerization. Compared with the chemical routes, electrochemical polymerization can obtain conjugated polymer fi lms on conductive substrates directly. This not only enlarges the scope of candidate polymers but also avoids the procedure of the fi lm coating.

Carbazole-based derivatives simultaneously possess carrier-transport properties and suffi ciently high tri-plet energy levels, and therefore, oligocarbazoles via 3(6), 9-linkages have been used as effective host mate-rials for phosphorescent metal complexes. [ 9 ] Polymers

1. Introduction

Electrochromism is defi ned as a reversible and visible change in the transmittance and/or refl ectance of a mate-rial as the result of electrochemical oxidation or reduc-tion. [ 1 ] This is an intriguing phenomenon for which there might be a wide range of applications, including optical switching devices, color displays, smart windows, sensors, memory elements, and camoufl age materials. [ 2 ] The prop-erty of electrochromism is not unique to conducting poly-mers, but is found in a variety of organic and inorganic materials. [ 3 ] Signifi cant effort has been put forth on elec-trochromic devices based on inorganic electrochromic sys-tems such as tungsten oxide (WO 3 ) and nickel oxide (NiO or Ni 2 O 3 ). [ 4 ] π-Conjugated organic polymers present improved processability and better color tunability than their inor-ganic and molecular counterparts. [ 5 ] Considerable effort

Macromol. Chem. Phys. 2014, 215, 1525−1532

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MacromolecularChemistry and Physics

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new strategies for the easy fabrication of electroactive poly(amine-amide) and poly(amine-imide) fi lms for elec-trochromic applications.

2. Results and Discussion

The synthetic route and chemical structures of the diamide-dicarbazole and dimide-dicarbazole monomers are shown in Scheme 1 . According to a previously reported procedure, [ 14 ] N -(4-aminophenyl)carbazole ( Cz-NH2 ) was synthesized by the cesium fl uoride-mediated condensation of carbazole with p -fl uoronitrobenzene, followed by a Pd/C-catalyzed hydrazine reduction. Cz6F-DA and CzSO2-DA were synthesized from Cz-NH2 with 2,2-bis(4-carboxy-phenyl)hexafl uoropropane and bis(4-carboxyphenyl) sul-fone, respectively, using triphenyl phosphite (TPP) and pyridine as condensing agents. The diimide-dicarbazole monomers of Cz6F-DI and CzSO2-DI were prepared by the reactions of Cz-NH2 with aromatic dianhydrides 6FDA and DSDA, respectively, followed by cyclodehydration with acetic anhydride and pyridine. Details of synthesis and characterization data of typical Cz6F-DA and Cz6F-DI are shown in the Supporting Information.

Figure S1 (Supporting Information) shows the FTIR spectra of Cz-NH2 and all the synthesized monomers. The amino group of Cz-NH2 showed a typical N−H stretching absorption pair at 3468 and 3373 cm −1 , which disappeared after condensation with dicarboxylic acids or dianhy-drides. The IR spectra of Cz6F-DA and CzSO2-DA showed

containing carbazole moieties in the main chain or side chain have attracted much attention because of their unique properties, which allow various optoelectronic applications such as photoconductive, electrolumines-cent, electrochromic, and photorefractive materials. [ 10 ] As a class of excellent electrochromic materials, triar-ylamine-containing high-performance polymers such as aromatic polyamides, polyimides, poly(amide-imide)s, and poly(1,3,4-oxadiazole)s have various useful properties such as easily forming relatively stable polarons (radical cations), high carrier mobility, high thermal stability, and good mechanical properties. [ 11 ] It has been demonstrated that N -substituted carbazoles can form extremely stable biscarbazoles upon anodic oxidation. [ 12 ] Therefore, var-ious carbazole-containing electrochomic polymeric fi lms have been prepared via the electrochemical coupling of carbazole units. [ 13 ] However, to our best knowledge, there are still no reports about the electrosynthesis and electro-chromic properties of electroactive polymers from amide or imide-containing carbazole derivatives. In this study, two diamide-dicarbazole monomers (coded with CzR-DA , Scheme 1 ) and two diimide-dicarbazole monomers ( CzR-DI ) were synthesized and their polymer fi lms were directly prepared on electrodes by electrochemical poly-merization of the monomers. The electrochemical and electrochromic properties of the electrogenerated fi lms were also investigated. The experimental results sug-gested that the electrogenerated polymer fi lms revealed reversible electrochemical redox reactions and obvious color changes upon electro-oxidation. This study provides

Scheme 1. Synthesis and electropolymerization of the diamide-dicarbazole and diimide-dicarbazole monomers.



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Facile Fabrication of Electrochromic Poly(amine-amide) and Poly(amine-imide) Films . . .

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formed on the working electrode sur-face. The increase in the redox wave cur-rent densities implied that the amount of conducting polymers deposited on the electrode was increasing. The elec-trodeposited polymer fi lms showed two oxidation peaks, which are attributed to their polaronic and bipolaronic states, respectively.

After being immersed in water, a free-standing polymer fi lm could be removed from the ITO-glass substrate. All the electrogenerated polymer fi lms are insoluble in polar organic solvents, such as N -methylpyrrolidine (NMP), N,N -dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO), and even in concentrated sulfuric acid. The insolu-bility of the electrogenerated polymers may be attributed to the fact that a tight packing of the polymer chains or some crosslinking reactions occurred during the electropolymerization process. The

real reason is not clear, and it needs further in depth studies. Figure S3 (Supporting Information) shows the FTIR spectra of representative poly(amine-amide) Cz6F-PA and poly(amine-imide) Cz6F-PI . The bands around 3312 and 1671 cm −1 can be respectively ascribed to the N−H and carbonyl stretching vibration of the amide groups in Cz6F-PA . The Cz6F-PI fi lm showed characteristic absorp-tion peaks at 1785 and 1723 cm −1 due to imide ring car-bonyl stretching vibrations. The absorptions around 2800–2900 cm −1 indicates that some of the electrolyte (Bu 4 NClO 4 ) may be trapped in the polymer fi lms. The electropolymerized poly(amine-amide) and poly(amine-imide) samples were also subjected to differential scan-ning calorimetry (DSC) and thermogravimetry (TGA). All the polymer fi lm samples did not show clear glass transi-tions on their DSC curves, possibly due to close packing or some degree of crosslinking between polymer chains. Typ-ical TGA curves of the representative polymers Cz6F-PA and Cz6F-PI in air atmosphere are depicted in Figure S4 (Supporting Information). These polymers exhibited good thermal stability with no remarked weight loss up to 450 °C in air.

The representative UV–vis absorption spectra of mono-mers Cz6F-DA and Cz6F-DI in CH 2 Cl 2 and the polymer fi lms of Cz6F-PA and Cz6F-PI in solid state on an ITO elec-trode are illustrated in Figure S5 (Supporting Information). The spectra of the monomers showed absorption bands with maximum peaks at 293 nm and absorption onsets at 361 and 352 nm, respectively. The red-shift of absorption maxima and onsets of the polymer fi lms means higher conjugation backbone in comparison with the monomers.

the characteristic amide absorption bands at around 3300 cm −1 (N−H stretching) and 1660–1690 cm −1 (amide carbonyl stretching). The characteristic imide absorption bands near 1782 cm −1 (asymmetric C=O stretching) and 1724 cm −1 (symmetric C=O stretching) could be observed in the IR spectra of Cz6F-DI and CzSO2-DI . Figure S2 (Sup-porting Information) illustrates the 1 H NMR spectra of diamide-dicarbazole Cz6F-DA and diimide-dicarbazole Cz6F-DI , and the spectra agree well with their proposed molecular structures.

Figure 1 presents a typical CV of Cz6F-DI in 0.1 M Bu 4 NClO 4 /CH 2 Cl 2 . For the fi rst positive potential scan, an oxidation peak at ca. 1.75 V was observed. From the fi rst reverse negative potential scan, two cathodic peaks were detected. In the second scan, a new oxidation peak appeared at 1.11 V that was the complementary anodic process of the cathodic peak at a lower potential. The observation of a new oxidation couple in the second potential scan implies that the Cz6F-DI radical cations were involved in very fast electrochemical reactions that produced a substance that was easier to oxidize than was the parent Cz6F-DI . In addition, when the potential was continuously cycled, we observed a progressive growth in all peak currents (Figure 2 c). This behavior suggests that the oxidative coupling of the radical cations of Cz6F-DI produced a continuous buildup of an electroactive and conductive layer on the electrode.

Figure 2 displays the successive cyclic voltammograms (CV) of 0.003 M monomers in 0.1 M Bu 4 NClO 4 /CH 2 Cl 2 solu-tions between 0 and 2.1 V at a potential scan rate of 150 mV s −1 . As the CV scan continued, polymer fi lm was

Figure 1. First (in black) and second (in red) CV cycles of 0.003 M Cz6F-DI in 0.1 M Bu 4 NClO 4 /CH 2 Cl 2 at a scan rate of 150 mV s −1 .



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peaks attributed to their polaronic and bipolaronic states, respectively. The half-wave potentials ( E 1/2 ) of the fi rst oxidation process of poly(amine-amide)s Cz6F-PA and CzSO2-PA were recorded at 0.99 V (vs Ag/AgCl), and those of poly(amine-imide)s Cz6F-PI and CzSO2-PI were

The electrochemical behavior of the electrodeposited polymer fi lms was investigated by cyclic voltammetry in a monomer-free Bu 4 NClO 4 /CH 2 Cl 2 solution. The quan-titative details are summarized in Table 1 . As shown in Figure 3 , all the polymer fi lms exhibited two oxidation

Figure 2. Repetitive cyclic voltammograms of 0.003 M monomers: a) Cz6F-DA, b) CzSO2-DA, c) Cz6F-DI and d) CzSO2-DI in 0.1 M Bu 4 NClO 4 /CH 2 Cl 2 solutions at a scan rate of 150 mV s −1 . The fi rst CV curves are marked in red.

Table 1. Optical and electrochemical properties of the electrosynthesized polymers.

Polymer UV–vis absorption a) [nm]

Oxidation potential b) [V]

Reduction potential b) [V]

Optical bandgap d) [eV]

HOMO e) [eV]

LUMO e) [eV]

λ max λ onset E onset E 1/2 Ox E pc c) E g E onset E 1/2 E onset E 1/2

Cz6F-PA 304 398 0.89 0.99, 1.29 − 3.12 5.32 5.35 2.18 2.21

CzSO2-PA 316 392 0.86 0.99, 1.26 − 3.16 5.29 5.35 2.13 2.18

Cz6F-PI 304 375 0.91 1.06, 1.35 −1.72 3.31 5.34 5.42 2.01 2.09

CzSO2-PI 308 387 0.88 1.10, 1.29 −1.62 3.20 5.38 5.46 2.18 2.26

a) UV–vis absorption maximum and onset for the polymer fi lms; b) Calculated from single scan CVs, versus Ag/AgCl in acetonitrile at a scan rate of 50 mV s −1 ; c) Irreversible peak potential; d) Optical bandgaps calculated from absorption edge of the polymer fi lms: E g = 1240/λ onset ; e) E HOMO = −( E Ox1 + 4.8) (eV); E LUMO = E HOMO – E g .



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of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the corre-sponding polymers were estimated from the E 1/2 ox values. Assuming that the HOMO energy level for the ferrocene/ferrocenium (Fc/Fc + ) standard is 4.80 eV with respect to the zero vacuum level, the HOMO levels for these poly-mers were calculated to be between 5.29 and 5.38 eV (relative to the vacuum energy level), whereas the values for the LUMO levels lay between 2.01 and 2.18 eV. Figure S6 (Supporting Information) shows the electrochemical behavior of the CzSO2-PA and CzSO2-PI fi lms at different

scan rates between 50 and 250 mV s −1 in 0.1 M Bu 4 NClO 4 /CH 3 CN. A linear dependence of the peak currents as a function of scan rates indicated that the electrochemical processes of these poly-mers are reversible and not diffusion limited.

Spectroelectrochemistry was used to study the changes in the absorption spectra and the information about the electronic structures of the polymers as a function of the applied potential. The electrogenerated polymer fi lms on ITO glass were switched between 0 and 1.4 V (for the PA fi lms) or 1.5 V (for the PI fi lms). The spectral changes of all the polymer fi lms upon poten-tial variation are compiled in Figure 4 . Their spectroelectrochemical behav-iors are very similar. We use Cz6F-PA as an example to explain the spec-troelectrochemical behavior of these polymers. In the neutral form, polymer Cz6F-PA exhibited strong absorption at 308 nm, characteristic π–π* transi-tions of the biscarbazole, but it was almost transparent in the visible and near-IR regions. Consequently, the fi lm is almost colorless. The optical band gap of polymer Cz6F-PA was esti-mated to be 3.11 eV from the onset of the π–π* transition at 398 nm. When the applied potential was increased to about 1.1 V, the spectra displayed an absorption peak at ca. 423 nm and a broadband that extended to the near-IR range, which we assigned to the for-mation of biscarbazole radical cations. The absorption band in the near-IR region may be attributed to an inter-valance charge transfer (IVCT) between states in which the positive charge is centered at different amino centers

determined at 1.06 and 1.10 V, respectively. The slightly higher oxidation voltages of the latter ones may be caused by the stronger electron-attracting nature of the imide ring. Furthermore, irreversible reduction waves for the formation of radical anions and dianions of the imide units in Cz6F-PI and CzSO2-PI were observed in the nega-tive side of the voltammograms at peak potentials E pc = –1.62 and –1.72 V, respectively (Figure 3 ). The irreversible behavior may be caused by a little unwanted delami-nation or dissolution of the radical anion and dianion products in DMF/electrolyte solution. The energy levels

Figure 3. Cyclic voltammograms of the polymer fi lms (top: Cz6F-PA and CzSO2-PA; bottom: Cz6F-PI and CzSO2-PI)) on the ITO-coated glass slide in 0.1 M Bu 4 NClO 4 /CH 3 CN at a scan rate of 50 mV s −1 .



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The polymer fi lms were electrodeposited onto ITO-coated glass, thoroughly rinsed, and then dried. Afterward, the gel electrolyte was spread on the polymer-deposited side of the electrode and the electrodes were sandwiched under atmospheric condition. To prevent leakage, an epoxy resin was applied to seal the device. As a typical example, an electrochromic device based on polymer CzSO2-PA was fabricated. The spectral and color changes of the electrochromic device based on CzSO2-PA upon oxidation are illustrated in Figure 6 . By the application of voltage to 2.4 V, the absorption bands at 424 and 986 nm gradually increased in intensity. Upon further oxidation at applied voltages to 2.9 V, a new broadband at about 840 nm grew up. When the voltage applied was increased (to a maximum of 2.9 V), the color of the cell changed from colorless (neutral) to yellow-green (semi-oxidized)

(biscarbazole). The IVCT phenomenon of the family of triarylamines with multiple amino centers has been reported in literature. [ 15 ] Upon further oxidation at applied potential to 1.4 V, the dication (bipolaron) band at 821 nm appeared, and the absorption at 423 nm decreased in intensity. The observed spectral changes of the Cz6F-PA fi lm were fully reversible upon varying the applied potential. In addition, they were associated with signifi cant color changes (from colorless to yellow-green, to green, and to blue) that were homogeneous across the ITO electrode surface and easy to detect with the naked eye (Figure 5 ). The structures of the diamide and diimide segments seem to be unimportant for the electrochemical and electrochromic behaviors of these polymers because the redox reactions originate from the bicarbazyl centers.

Figure 4. Spectral changes of the polymer fi lms of a) Cz6F-PA, b) CzSO2-PA, c) Cz6F-PI, and d) CzSO2-PI on the ITO-coated glass substrate in 0.1 M Bu 4 NClO 4 /CH 3 CN at various applied potentials (vs Ag/AgCl).



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and green (fully oxidized). We believe that optimization could further improve the device performance and fully explore the potential of these electrochromic materials.

3. Conclusion

Two series of novel carbazole-endcapped aromatic diamide and diimide monomers were synthesized from the condensation of N -(4-aminophenyl)carbazole with the corresponding aromatic dicarboxylic acids and tetra-carboxylic dianhydrides. Polymer fi lms with biscarbazole groups were successfully electrodeposited onto the ITO electrode surface by electropolymerization of the mono-mers in Bu 4 NClO 4 /CH 3 CN. The electrochemically gener-ated polymer fi lms exhibited two reversible oxidation redox couples due to successive oxidations of the biscarba-zole unit. These polymer fi lms also revealed excellent elec-trochemical and electrochromic stability, with coloration change from a colorless neutral state to yellow–green-, green-, and blue-oxidized forms. This study provides new strategies for the easy fabrication of electroactive poly(amine-amide) and poly(amine-imide) fi lms for elec-trochromic applications.

Figure 6. a) Spectroelectrochemistry of the electrochromic device , b) color change of the device at various applied voltages, and c) cyclic voltammogram of the polymer fi lm of CzSO2-PA in the electrochromic device.

Figure 5. Chemical structure of the polymers and their electrochromism at the different applied potentials.



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Supporting Information

Supporting Information is available from the Wiley Online Library or from the author.

Acknowledgements: The authors thank the Ministry of Science and Technology, Taiwan for the fi nancial support.

Received: April 2, 2014 ; Revised: May 19, 2014 ; Published online: June 24, 2014 ; DOI: 10.1002/macp.201400171

Keywords: carbazole ; electrochemical polymerization ; electro-chromic properties ; polyamides and polyimides ; redox polymers

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for Macromol. Chem. Phys., DOI: 10.1002/macp.201400171

Facile Fabrication of Electrochromic Poly(amineamide) and Poly(amine-imide) Films Via Carbazole-Based Oxidative Coupling Electropolymerization Sheng-Huei Hsiao,* Jun-Wen Lin

1


Facile Fabrication of Electrochromic Poly(amine-amide) and

Poly(amine-imide) Films via Carbazole-based Oxidative Coupling

Electropolymerization

Sheng-Huei Hsiao,* Jun-Wen Lin

Materials. Carbazole (Acros), 4-fluoronitrobenzene (Acros), cesium fluoride (CsF)

(Acros), 10% palladium on charcoal (Pd/C, Fluka), triphenyl phosphite (TPP, Acros),

and pyridine (Py, Wako) were used as received. N,N-Dimethylacetamide (DMAc,

Fluka) and N-methyl-2-pyrrolidone (NMP, Tedia) were dried over calcium hydride for

24 h, distilled under reduced pressure, and stored over 4 Å molecular sieves in a

sealed bottle. The aromatic dicarboxylic acids such as bis(4-carboxyphenyl) sulfone

(New Japan Chemicals Co.) and 2,2-bis(4-carboxyphenyl)hexafluoropropane (TCI)

were used as received. Commercially available tetracarboxylic dianhydrides such as

2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA, Hoechst

Celanese) and 3,3’,4,4’-diphenylsulfonetetracarboxylic dianhydride (DSDA, New

Japan Chemical Co.) were heated at 250 oC in vacuo for 3 h before use.

Tetrabutylammonium perchlorate (Bu4NClO4, from Arcos) were recrystallized twice

by ethyl acetate under nitrogen atmosphere and then dried in vacuo prior to use. All

other reagents were used as received from commercial sources.

Instrumentation. Infrared (IR) spectra were recorded on a Horiba FT-720 FT-IR

spectrometer. Elemental analyses were run in a Heraeus VarioEL III CHNS

2

elemental analyzer. 1H NMR spectra were measured on a Bruker AVANCE 500

FT-NMR system with tetramethylsilane as an internal standard. Electrochemical

measurements were performed with a CH Instruments 750A electrochemical analyzer.

The polymers were electropolymerized from 0.003 M monomers and 0.1 M

Bu4NClO4 in dichloromethane solution via repetitive cycling at a scan rate of 150

mV/s. Voltammograms are presented with the positive potential pointing to the left

and with increasing anodic currents pointing downwards. Cyclic voltammetry was

conducted with the use of a three-electrode cell in which ITO (polymer films area

about 0.8 cm × 1.25 cm) was used as a working electrode. A platinum wire was used

as an auxiliary electrode. All cell potentials were taken with the use of a home-made

Ag/AgCl, KCl (sat.) reference electrode. Ferrocene was used as an external reference

for calibration (+0.48 V vs. Ag/AgCl). Spectroelectrochemistry analyses were carried

out with an electrolytic cell, which was composed of a 1 cm cuvette, ITO as a

working electrode, a platinum wire as an auxiliary electrode, and a Ag/AgCl reference

electrode. Absorption spectra in the spectroelectrochemical experiments were

measured with an Agilent 8453 UV-Visible spectrophotometer.

Monomer Synthesis. The synthesis of Cz6F-DA was used as an example to illustrate

the general synthetic route used to produce the diamide-dicarbazole monomers. In a

50 mL round-bottom flask equipped with a stirring bar, a mixture of 2.10 g (8.2 mmol)

of N-(4-aminophenyl)carbazole (Cz-NH2), 1.60 g (4.1 mmol) of

2,2-bis(4-carboxyphenyl)hexafluoropropane, 0.60 mL of triphenyl phosphite (TPP),

0.20 mL of pyridine, and 1 mL of NMP was heated with stirring at 120 °C for 3 h. The

solution was poured slowly with stirring into 150 mL of methanol to precipitate white

product. The precipitated product was collected by filtration, washed repeatedly with

3

methanol and hot water, and dried in vacuum at 80 oC to give 0.54 g of the desired

monomer (Cz6F-DA) as white powder in 33 % yield. Mp = 173 - 185 oC measured by

DSC at 10 oC/min.

IR (KBr) (Figure S1): 3315 cm-1

(amide N-H stretching); 1666 cm-1

(amide

C=O stretching). 1H NMR (500 MHz, CDCl3, δ, ppm) (Figure S2): 7.30 (t, J = 7.0 Hz,

4H, Hb), 7.40 (m, 8H, Hc + Hd), 7.56 (d, J = 8.5 Hz, 4H, Hh), 7.59 (d, J = 8.5 Hz, 4H,

He), 7.91 (d, J = 8.5 Hz, 4H, Hf), 7.96 (d, J = 8.5 Hz, 4H, Hf), 8.16 (d, J = 8.5 Hz, 4H,

Ha), 8.03 (d, J = 8.8 Hz, 2H, Hf), 8.32 (s, 2H, amide).

N N NN

H

C

O CF3

CF3

C

O H

a

b cd

e f g h

The synthesis of Cz6F-DI was used as an example to illustrate the general

synthetic route used to produce the diimide-dicarbazole monomers. A mixture of 2.58

g (10.0 mmol) of N-(4-aminophenyl)carbazole (Cz-NH2) and 2.22 g (5.0 mmol)

2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) was dissolved in

15 ml of anhydrous DMAc in a 50 mL round-bottom flask. The mixture was stirred 10

min at room temperature, and then added 4 ml of acetic anhydride and 2 mL of

pyridine. After stirring at room temperature for 1 h, the solution was poured slowly

with stirring into 150 mL of methanol, and then the precipitate pale yellow product

was collected by filtration, washed with water, and dried in vacuum at 80 oC to give

4.1 g (88% yield) of the desired monomer (Cz6F-DI) as pale yellow powder. Mp =

355 - 360 oC, measured by DSC at 10

oC/min.

IR (KBr) (Figure S1): 1782 cm-1

(asymmetric imide C=O stretching), 1724 cm-1

4

(symmetric imide C=O stretching). 1H NMR (500 MHz, CDCl3, δ, ppm) (Figure S2):

7.33 (t, J = 7.5 Hz, 4H, Hb), 7.45 (t, 4H, Hc), 7.53 (d, J = 8.5 Hz, 4H, Hd), 7.72 (d, J =

9.0 Hz, 4H, He), 7.77 (d, J = 9.0 Hz, 4H, Hf), 7.97 (d, J = 8.5 Hz, 2H, Hg), 8.05 (s, 2H,

Hi), 8.13 (d, J = 8.5 Hz, 2H, Hh), 8.32 (d, J = 8.0 Hz, 4H, Ha).

N N

O

O

O

O

CF3F3C

NN

a

b cd

e fg

h

i

Electrochemical Polymerization. Electrochemical polymerization was performed

with a CH Instruments 750A electrochemical analyzer. The polymers were

synthesized from 0.003 M monomers and 0.1 M Bu4NClO4 in dichloromethane

solution via cyclic voltammetry repetitive cycling between 0 and 2.1 V at a scan rate

of 150 mV/s for ten cycles. The polymer was deposited onto the surface of the

working electrode (platinum disc or ITO/glass surface, polymer films area about 0.8

cm × 1.25 cm), and the film was rinsed with plenty of acetone for the removal of

inorganic salts and other organic impurities formed during the process.

Fabrication of the Electrochromic Devices. Electrochromic polymer films were

electrodeposted on the ITO-coated glass substrate by the electrochpolymerization

method described above. A gel electrolyte based on PMMA (Mw: 120000) and

LiClO4 was plasticized with propylene carbonate to form a highly transparent and

conductive gel. PMMA (1 g) was dissolved in dry acetonitrile (4 mL), and LiClO4

(0.1 g) was added to the polymer solution as supporting electrolyte. Then propylene

carbonate (1.5 g) was added as plasticizer. The mixture was then gently heated until

5

gelation. The gel electrolyte was spread on the polymer-coated side of the electrode,

and the electrodes were sandwiched. Finally, an epoxy resin was used to seal the

device.

6

Figure S1. IR spectra of Cz-NH2 and all the synthesized compounds.

7

Figure S2. 1H NMR spectra of diamide-dicarbazole Cz6F-DA and

diimide-dicarbazole Cz6F-DI in CDCl3.

8

Figure S3. IR spectra of the electrosynthesized films of diamide-dicarbazole

Cz6F-DA and diimide-dicarbazole Cz6F-DI.

Figure S4. TGA thermograms of the electrogenerated films of Cz6F-PA and Cz6F-PI

at a heating rate of 20 oC/min under an air flow.

9

Figure S5. UV–vis absorption spectra of Cz6F-DA and Cz6F-DI in CH2Cl2 and

Cz6F-PA and Cz6F-PI polymer films on ITO-glass.

10

Figure S6. Scan rate dependence of CzSO2-PA and CzSO2-PI films on the ITO-coated glass slide in CH3CN containing 0.1 M Bu4NClO4 at

different scan rates between 50 and 250 mV/s.

facile fabrication of electrochromic poly(amineamide) and...

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