Electrosynthesis and characterization of an electrochromic material from poly(1,4-bis(2-thienyl)-benzene) and its application in electrochromic devices

1,4-Bis(2-thienyl)-benzene monomer is successfully synthesized via coupling reaction. Poly(1,4-bis(2-thienyl)-benzene) (PBTB) is electrochemically synthesized and characterized. Resulting polymer film has distinct electrochromic properties. Its application in electrochromic devices (ECDs) is discussed. PBTB is switched between yellow in the neutral state and green in the oxidized state. Electrochromic switching of PBTB film is performed and the polymer film shows a maximum optical contrast (ΔT %) of 44.8% at 610 nm in visible region with a response time of 1.6 s. The coloration efficiency (CE) of PBTB is calculated to be 162 cm² C⁻¹. Electrochromic device (ECD) based on PBTB and poly(3,4-ethylenedioxythiophene) (PEDOT) is also constructed and characterized. Maximum contrast (ΔT %) and switching time of the device are measured as 29.5% and 0.43 s at 628 nm. The CE of the device is calculated to be 408.9 cm² C⁻¹. Clear change from green (at neutral state) to blue color (at full oxidized state) of this ECD is demonstrated with reasonable cycle life.     

Synthesis and characterization of conducting copolymer of Trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene with EDOT

Ferrocene‐substituted conducting polymer namely poly(trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene‐co‐3,4‐ethylenedioxythiophene) [P(MTFE‐co‐EDOT)] was synthesized and its electrochromic properties were studied. Monomer, MTFE, was obtained using 2‐(ferrocenyl)ethene and 3‐methyl‐4‐bromothiophene. The structure of monomer was determined via Fourier transform infrared spectroscopy (FTIR), ¹H‐NMR, and ¹³C‐NMR techniques. The copolymer was synthesized using this monomer and EDOT. The resulting copolymer P(MTFE‐co‐EDOT) was characterized by cyclic voltammetry, FTIR, scanning electron microscopy, atomic force microscopy, and UV–vis spectroscopy. The conductivity measurements of copolymer and PEDOT were accomplished by the four‐probe technique. Although poly(trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene) [P(MTFE)] reveals no electrochromic activity, its copolymer with EDOT has two different colors (violet and gray). Band gap (E_g) and λ_max of P(MTFE‐co‐EDOT) were determined. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of poly(thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester‐co‐N‐methylpyrrole) and its application in an electrochromic device

Copolymer of thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester (TAPE) with N‐methylpyrrole (NMPy) was synthesized by potentiostatic electrochemical polymerization in acetonitrile–tetrabutylammonium tetrafluoroborate solvent–electrolyte couple. The chemical structures were confirmed via Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and UV–vis spectroscopy. Electrochromic and spectroelectrochemical properties of poly(TAPE‐co‐NMPy) [P(TAPE‐co‐NMPy)] were investigated. Results showed that the copolymer revealed color change between light yellow and green upon doping and dedoping of the copolymer, with a moderate switching time. Furthermore, as an application, dual‐type absorptive/transmissive polymer electrochromic device (ECD) based on poly(TAPE‐co‐NMPy) and poly(3,4‐ethylene dioxythiophene) (PEDOT) have been assembled, where spectroelectrochemistry, switching ability, stability, and optical memory of the ECD were investigated. Results showed that the device exhibited good optical memory and stability with moderate switching time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1988–1994, 2006     

Electrochromic properties and electrochromic device application of copolymer of N‐(4‐(3‐thienyl methylene)‐oxycarbonylphenyl)maleimide with thiophene

A new copolymer of N‐(4‐(3‐thienyl methylene)‐oxycarbonylphenyl)maleimide (MBThi) with thiophene [P(MBThi‐co‐Th)] was synthesized electrochemically in the presence of tetrabutylammonium tetrafluoroborate as the supporting electrolyte, in acetonitrile/borontrifluoride ethylether solvent mixture (80 : 20, v/v). Spectroelectrochemical analysis of the resulting copolymer reflected electronic transitions at 440, 730, and ～1000 nm, revealing π–π* transition, polaron, and bipolaron band formation, respectively. Switching ability was evaluated by a kinetic study via measuring the transmittance (%T) at the maximum contrast. Dual‐type polymer electrochromic devices (ECDs) based on P(MBThi‐co‐Th) and poly(ethylene dioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, switching ability, and stability of the devices were investigated by UV–vis spectroscopy and cyclic voltammetry. These devices exhibit low switching voltages (between 0.0 and +2.0 V) and short switching times with reasonable switching stability under atmospheric conditions. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 4500–4505, 2006     

Electrochromic properties of a copolymer of 1‐4‐di[2,5‐di(2‐thienyl)‐1H‐1‐pyrrolyl]benzene with EDOT

Homopolymer of 1‐4‐di[2,5‐di(2‐thienyl)‐1H‐1‐pyrrolyl]benzene and its copolymer with 3,4‐ethylenedioxythiophene (EDOT) were electrochemically synthesized and characterized. Resulting homopolymer and copolymer films have distinct electrochromic properties. At the neutral state, homopolymer has λ_max due to the π‐π* transition as 410 nm and E_g was calculated as 2.03 eV. The resultant copolymer revealed multichromism through the entire visible region, displaying red‐violet, brownish yellow green, and blue colors with the variation of the applied potential. For the copolymer, λ_max and E_g were found to be 450 nm and 1.66 eV, respectively. Double potential step chronoamperometry experiment shows that homopolymer and copolymer films have good stability, fast switching times, and high optical contrast in NIR region as 41 and 30%, respectively. Copolymerization with EDOT not only decreases the band gap, E_g, but also enhances the electrochromic properties. Hence, electrochemical copolymerization is considered to be a powerful tool to improve the electrochromic properties of N‐substituted 2,5‐di(2‐thienylpyrrole) derivatives. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Characteristics of dual‐type electrochromic devices based on poly(ethylene oxide) copolymers

Dual‐type polymer electrochromic devices based on [(3‐thienyl)methylmethacrylate]‐co‐[p‐vinyl benzyloxy poly(ethylene oxide)]/polythiophene and thiophene‐capped poly(ethylene oxide)/polythiophene and ethylene dioxythiophene were constructed via electropolymerization. Spectroelectrochemistry, switching ability and stability of the devices were investigated using UV‐visible spectrophotometry and cyclic voltammetry. These devices exhibit low switching voltages and short switching times with reasonable switching stability under atmospheric conditions. Copyright © 2006 Society of Chemical Industry     

Specroelectrochemical,switching kinetics,and chronoamperometric studies of dibenzyl derivative of poly(3,4‐propylenedioxythiophene) thin‐film‐based electrochromic device

The dibenzyl derivative of poly(3,4‐propylenedioxythiophene) (PProDOT‐Bz₂) thin film is deposited onto ITO‐coated glass substrate by electropolymerization technique. The electropolymerization of ProDOT‐Bz₂ is carried out by a three‐electrode electrochemical cell. The cyclic voltammogram shows the redox properties of electrochemically prepared films deposited at different scan rates. The thin films prepared were characterized for its morphological properties to study the homogeniety. Classic six‐layer structure of PProDOT‐Bz₂ electrochromic device using this material was fabricated and reported for the first and its characterizations such as spectroelectrochemical, switching kinetics, and chronoamperometric studies are performed. The color contrast of the thin film and the device achieved are 64 and 40%, respectively, at λ_max (628 nm). The switching time is recorded and the observed values are 5 s from the coloring state to the bleaching state and vice versa. The chronoamperometry shows that the device performed up to 400 cycles, and it is capable of working up to 35 cycles without any degradation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40717.     

Electrochromic properties of some bis‐chalcone derivatives‐based nanofibers

Two bis‐chalcone derivatives, (2E,6E)‐2,6‐bis[(thiophen‐2‐yl)methylene]cyclohexanone ( C1 ) and (2E,6E)‐2,6‐bis[(furan‐2‐yl)methylene]cyclohexanone ( C2 )‐based electrochromic (EC) nanofibers were produced in the presence of poly(methyl methacrylate) (PMMA) as supporting polymer using the electrospinning technique. The scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy were used to examine morphology and chemical compositions of nanofibers before and after stability test. SEM images of the obtained smooth and bead‐free nanofibers before the stability test showed that both bis‐chalcone derivatives were homogeneously dispersed on the surface of the electrospun nanofibers. Nanofibers of bis‐chalcone derivatives were characterized with Fourier‐transform infrared spectroscopy. The electrochemical and EC properties of these bis‐chalcone derivatives were investigated. The C1 ‐PMMA nanofiber‐based electrochromic device (ECD) showed higher ΔT_max (41.47%) than that of the C2 ‐PMMA nanofiber‐based ECD (4.67%) during coloration/bleaching at 715 nm. The switching times for coloration and bleaching of C1 ‐PMMA nanofiber‐based ECD were found to be 4.42 and 1.12 s, respectively, and the coloration efficiency was 136.18 cm²/C. Repeated cyclic voltammograms and 1000 cycles of chronoamperometric measurements of the bis‐chalcone derivatives indicated that ECDs have long‐term redox stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46010.     

Electrochromic properties of a novel low band gap conjugated copolymer based on 1,4-bis(2-thienyl)-naphthalene and 3,4-ethylenedioxythiophene

1,4-Bis(2-thienyl)-naphthalene (BTN) monomer is successfully synthesized via coupling reaction. A novel copolymer based on 1,4-bis(2-thienyl)-naphthalene (BTN) and 3,4-ethylenedioxythiophene (EDOT) is electrochemically synthesized and characterized. Characterizations of the resulting copolymer P(BTN-co-EDOT) are performed by cyclic voltammetry (CV), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetry (TG). At the neutral state of the copolymer, the π–π* transition absorption peak is located at 515 nm and the optical band gap (E_g) is calculated as 1.73 eV. Spectroelectrochemical analysis reveals that the copolymer film has distinct electrochromic properties from that of the BTN homopolymer film and shows six different colors under various potentials. The copolymer film shows a maximum optical contrast (ΔT%) of 48.4% at 504 nm with a response time of 0.88 s and of 45.2% at 770 nm with a response time of 0.84 s. An electrochromic device (ECD) based on P(BTN-co-EDOT) and poly(3,4-ethylenedioxythiophene) (PEDOT) is constructed and characterized. The optical contrast (ΔT%) at 645 nm is found to be 21.1% and response time is measured as 0.41 s. The coloration efficiency (CE) of the device is calculated to be 154 cm² C⁻¹ at 645 nm.     

Synthesis and characterization of new aromatic poly(amide–imide)s based on 4‐aryl‐2,6‐bis(4‐trimellitimidophenyl) pyridines

New diimide–dicarboxylic acids, ie 4‐phenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis‐(4‐trimellitimidophenyl)pyridine, were synthesized by the condensation reaction of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis(4‐aminophenyl)pyridine with trimellitic anhydride in glacial acetic acid or dimethylformamide. The monomers were fully characterized by FT‐IR and NMR spectroscopies, and elemental analyses. A series of novel poly(amide–imide)s with inherent viscosities of 0.68–0.87 dl g^?1 was prepared from the two diimide–diacids with various aromatic diamines by direct polycondensation. The poly(amide–imide)s were characterized by FT‐IR and NMR spectroscopies. The λ_max data for the resulting poly(amide–imide)s were in the range of 260–292 nm. These polymers exhibited good solubilities in polar aprotic solvents. The 10 % weight loss temperatures are above 485 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry     

Highly fluorinated poly(ether‐imide)s derived from 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether and aromatic dianhydrides

A new diamine, 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether (FPAPE) was synthesized through the Suzuki coupling reaction of 2,2′‐diiodo‐4,4′‐dinitrodiphenyl ether with 3,4,5‐trifluorophenylboronic acid to produce 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐dinitrodiphenyl ether (FPNPE), followed by palladium‐catalyzed hydrazine reduction of FPNPE. FPAPE was then utilized to prepare a novel class of highly fluorinated all‐aromatic poly(ether‐imide)s. The chemical structure of the resulting polymers is well confirmed by infrared and nuclear magnetic resonance spectroscopic methods. Limiting viscosity numbers of the polymer solutions at 25 °C were measured through the extrapolation of the concentrations used to zero. M_n and M_w of these polymers were about 10 000 and 25 000 g mol^?1, respectively. The polymers showed a good film‐forming ability, and some characteristics of their thin films including color and flexibility were investigated qualitatively. An excellent solubility in polar organic solvents was observed. X‐ray diffraction measurements showed that the fluoro‐containing polymers have a nearly amorphous nature. The resulting polymers had T_g values higher than 340 °C and were thermally stable, with 10% weight loss temperatures being recorded above 550 °C. Based on the results obtained, FPAPE can be considered as a promising design to prepare the related high performance polymeric materials. Copyright © 2011 Society of Chemical Industry     

Synthesis and spectroelectrochemistry of dithieno(3,2‐b:2′,3′‐d)pyrrole derivatives

New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH₂), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH₂), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (¹H‐NMR and ¹³C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH₂ and DTP–alkyl–NH₂ resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH₂)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.     

Synthesis and properties of new aromatic poly(ester‐imide)s derived from 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl) pyridine and various dihydroxy compounds

A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g^?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. The ultraviolet λ_max values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T_10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry     

Smart sunglasses based on electrochromic polymers

Smart sunglasses based on electrochromic polymers are proposed and developed in this study. This article discusses the design, processing, and the optical and electrical performance of a prototype smart sunglasses based on cathodic electrochromic (EC) polymers, which show several merits compared with traditional materials for sunglasses lens as well as other smart window materials. It is a multilayer design of device. The conjugated polymer, poly[3,3‐dimethyl‐3,4‐dihydro‐2H‐thieno [3,4‐b] [1,4]dioxepine] (PProDOT‐Me₂), is utilized as the electrochromic working layer. The counter layer of the device is vanadium oxide (V₂O₅) film, which serves as an ion storage layer. There is also a polymer gel electrolyte acting as the ionic transport layer, sandwiched between the working and counter layers. The characteristics of the prototype device are reported, including transmittance (%T), driving power, response time, open circuit memory, and lifetime. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Synthesis and characterization of novel aromatic poly(amide‐imide)s derived from 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl or 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl and various aromatic diamines

New aromatic diimide‐dicarboxylic acids having kinked and cranked structures, 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl (2a) and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl (2b), were synthesized by the reaction of trimellitic anhydride with 2,2′‐bis(4‐aminophenoxy)biphenyl (1a) and 2,2′‐bis(4‐aminophenoxy)‐1,1′‐binaphthyl (1b), respectively. Compounds 2a and 2b were characterized by FT‐IR and NMR spectroscopy and elemental analyses. Then, a series of novel aromatic poly(amide‐imide)s were prepared by the phosphorylation polycondensation of the synthesized monomers with various aromatic diamines. Owing to structural similarity, and a comparison of the characterization data, a model compound was synthesized by the reaction of 2b with aniline. The resulting polymers with inherent viscosities of 0.58–0.97 dl g^?1 were obtained in high yield. The polymers were fully characterized by FT‐IR and NMR spectroscopy. The ultraviolet λ_max values of the poly(amide‐imide)s were also determined. The polymers were readily soluble in polar aprotic solvents. They exhibited excellent thermal stabilities and had 10% weight loss at temperatures above 500 °C under a nitrogen atmosphere. Copyright © 2003 Society of Chemical Industry     

Synthesis and characterization of new optically active poly(amide‐imide‐urethane) thermoplastic elastomers,derived from 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine‐p‐aminobenzoic acid) and PEG‐MDI

A new class of optically active poly(amide‐imide‐urethane) was synthesized via two‐step reactions. In the first step, 4,4′‐methylene‐bis(4‐phenylisocyanate) (MDI) reacts with several poly(ethylene glycols) (PEGs) such as PEG‐400, PEG‐600, PEG‐2000, PEG‐4000, and PEG‐6000 to produce the soft segment parts. On the other hand, 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine‐p‐amidobenzoic acid) (2) was prepared from the reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine) diacid chloride with p‐aminobenzoic acid to produce hard segment part. The chain extension of the above soft segment with the amide‐imide 2 is the second step to give a homologue series of poly(amide‐imide‐urethanes). The resulting polymers with moderate inherent viscosity of 0.29–1.38 dL/g are optically active and thermally stable. All of the above polymers were fully characterized by IR spectroscopy, elemental analyses, and specific rotation. Some structural characterization and physical properties of this new optically active poly(amide‐imide‐urethanes) are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2288–2294, 2004     

Multicolor electrochromic and pH-sensitive nanocomposite thin film based on polyoxometalates and polyviologen

A multiple-colored electrochromic composite film of polyoxometalates (P₂W₁₈) and poly(hexyl viologen) (PXV) is fabricated by layer-by-layer (LbL) self-assembly method. The P₂W₁₈/PXV composite film exhibits a linear increase in film thickness with assembly processing, and undergoes a colorless to blue to violet transition over the potential range from +0.1 to −0.9 V. The optical contrast, response time and stability for the as-prepared films are carefully investigated. These results show the validation of an LbL method based intermixing strategy for the design of tunable-color electrochromic thin films. The composite film can also be used as a pH sensor because of the pH dependence of its electrochemical response.     

Synthesis and characterization of novel optically active poly(amide–imide)s containing N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) was reacted with L ‐valine in a mixture of acetic acid and pyridine (3:2) at room temperature, and then was refluxed at 90–100 °C, N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid was obtained in quantitative yield. The imide–acid was converted to N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride by reaction with thionyl chloride. Rapid and highly efficient synthesis of a number of poly(amide–imide)s was achieved under microwave irradiation using a domestic microwave oven by polycondensation of N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride with six different derivatives of 5,5‐disubstituted hydantoin compounds in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. A suitable organic medium was o‐cresol. The polycondensation proceeded rapidly, compared with conventional melt polycondensation and solution polycondensation and was almost completed within 8 min, giving a series of poly(amide–imide)s with inherent viscosities in the range 0.15–0.36 dl g^?1. The resulting poly(amide–imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, elemental analysis, inherent viscosity (η_inh) measurements, solubility testing and specific rotation measurements. The thermal properties of the poly(amide–imide)s were investigated by using thermogravimetric analysis. Copyright © 2004 Society of Chemical Industry     

High cycling stability and well printability poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)/multi‐walled carbon nanotube nanocomposites via in situ polymerization applied on electrochromic display

A high cycling stability material and an additive manufacturing method are reported for the fabrication of solid electrochromic devices. The poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)/multi‐walled carbon nanotube (PEDOT:PSS/MWCNT) nanocomposites were synthesized via in situ polymerization. A carboxymethyl cellulose gel was used as the ink vehicle for screen printing. The electrochromic (EC) performance of films patterned by screen printing was also examined. The results of characterization indicate that strong interfacial interactions occurred between PEDOT:PSS and the MWCNTs and the MWCNTs formed a network in these conducting polymers film, so the composite was more conductive than pure PEDOT:PSS. Devices containing PEDOT:PSS/MWCNTs were more stable after 1000 cycles, exhibited higher rate of ion exchange and faster increases in current. The composite containing 0.3 wt % MWCNTs also had a 23% higher color contrast (ΔE*) than pure PEDOT:PSS at 2.5 V applied voltages. The EC inks with well printability not only can be used to print large area films, but also can print fine lines and pixel‐type dots in displays. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45943.     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

A novel fluorinated bis(ether amine) monomer, 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy) naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,6‐dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel trifluoromethylated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two‐stage process with thermal imidization of poly(amic acid) films. Most of the resulting polyimides were highly soluble in a variety of organic solvents and could afford transparent and tough films via solution casting. These polyimides exhibited moderately high glass transition temperatures (T_gs) of 249–311 °C, high thermal stability and good mechanical properties. Low moisture (0.19–0.85 %), low dielectric constants (2.49–3.59 at 10 kHz), and low color intensity were also observed. For a comparative study, a series of analogous polyimides based on 2,6‐bis(4‐aminophenoxy)naphthalene were also prepared and characterized. Copyright © 2005 Society of Chemical Industry