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     

Conducting copolymers of polytetrahydrofuran and their electrochromic properties

Living polytetrahydrofuran (PTHF) was terminated with sodium thiophene methonate to yield a polymer with a thiophene group at one end. Copolymerizations of PTHF with pyrrole and thiophene were achieved in water‐p‐toluene sulfonic acid and acetonitrile‐tetrabutylammonium tetrafluoroborate (TBAFB) solvent‐electrolyte couples via constant potential electrolyses. Characterizations of the samples were performed by NMR, cyclic voltammetry, FT‐IR, thermal analyses, and scanning electron microscopy. Electrical conductivities were measured by the four‐probe technique. PTHF/PTh film that was deposited on ITO‐glass in a dichloromethane‐TBAFB solvent‐electrolyte couple was found to exhibit electrochromic behavior and it electrochemically switches between blue oxidized and red reduced states. Optical analyses were carried out to investigate the electronic structure of PTHF/PTh electrochromic copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1014–1023, 2005     

Tuning of electrochromic properties by copolymerization of monoalkoxythiophenes and dialkoxythiophenes

Monoalkoxysubstituted and dialkoxysubstitued thiophene monomers were synthesized by the nucleophilic substitution and transetherification reactions. Electrochemical homopolymerization of 3‐octyloxythiophene (OOT) and 3,4‐dioctyloxythiophene (DOOT), copolymerization of OOT with DOOT were performed via potentiodynamic and potentiostatic methods in the supporting electrolyte. Both the copolymer and homopolymers were characterized via cyclic voltammetry, scanning electron microscopy, gel permeation chromatography, and spectroelectrochemical analysis. In the redox process of the polymers, it was linear relationship between the peak current and the scanning rate in their cyclic voltammograms. The copolymer of P(OOT‐co‐DOOT) showed obvious change of color between red and bright blue in reduced and oxidized states, that has a great difference with the homopolymers. The morphology studies indicated that the electrochemical deposition of P(OOT‐co‐DOOT) proceeds via a mechanism of nucleation and two‐dimensional growth. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Copolymerization of N‐(4‐carboxyphenyl) itaconimide or N‐(4‐carboxyphenyl) itaconamic acid with methyl methacrylate

This paper describes the synthesis and characterization of N‐(4‐carboxyphenyl) itaconamic acid (CPA) and N‐(4‐carboxyphenyl) itaconimide (CPI) obtained by reacting itaconic anhydride with p‐aminobenzoic acid. Structural and thermal characterization of CPA and CPI was done using ¹H‐NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of CPA or CPI with methyl methacrylate (MMA) in solution was carried out at 60 °C using azobisisobutyronitrile as an initiator and dimethyl acetamide or THF as solvent. Feed compositions having varying mole fractions of CPA or CPI ranging from 0.05–0.20 or 0.1–0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by ¹H‐NMR and elemental analysis. Copolymer composition was determined using percentage nitrogen content. The reactivity ratios were r₁ (MMA) = 0.68 ± 0.06 and r₂ (CPI) = 0.46 ± 0.06. The intrinsic viscosity [η] was determined using an Ubbelohde suspension level viscometer. [η] decreased with increasing mole fraction of N‐(p‐carboxyphenyl) itaconimide or N‐(p‐carboxyphenyl) itaconamic acid in copolymers. Glass transition temperature and thermal stability of the copolymers were determined using DSC and thermogravimetric analysis, respectively. The glass transition temperature (T_g) as determined from DSC scans increased with increasing amounts of CPA or CPI in copolymers. A significant improvement in the char yield was observed upon copolymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1909–1915, 2005     

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     

Electrosynthesis and characterization of an electrochromic material from poly(1,6‐bis(2‐thienyl)pyrene) and its application in electrochromic device

Electrochemical polymerization of 1,6‐bis(2‐thienyl)pyrene (BTP) could be achieved in acetonitrile/dichloromethane (ACN/DCM) (1:1, by volume) solution containing sodium perchlorate (NaClO₄) as a supporting electrolyte. The resulting polymer poly(1,6‐bis(2‐thienyl)pyrene) (PBTP) were characterized by cyclic voltammetry, UV–vis spectroscopy, and scanning electron microscopy. The resulting polymeric film has distinct electrochromic properties and exhibits three different colors under various potentials. Moreover, the PBTP film showed reasonable optical contrast (DT %) at 700 nm is found to be 29% and satisfactory response time is measured as 1.3 s. An electrochromic device (ECD) based on PBTP and poly(3,4‐ethylenedioxythiophene) was also constructed and characterized. This ECD has these qualities: quick switching time, reasonable contrast, and good optical memories and redox stability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39770.     

Electrochromic properties of a novel low band gap conductive copolymer

A copolymer of 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole (DTTP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized. The resultant copolymer P(DTTP-co-EDOT) was characterized via cyclic voltammetry, FTIR, SEM, conductivity measurements and spectroelectrochemistry. Copolymer film has distinct electrochromic properties. It has four different colors (chestnut, khaki, camouflage green, and blue). At the neutral state λ_max due to the π-π^* transition was found to be 487 nm and E_g was calculated as 1.65 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (less than 1 s) and good optical contrast (20%).An electrochromic device based on P(DTTP-co-EDOT) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed and characterized. The device showed reddish brown color at −0.6 V when the P(DTTP-co-EDOT) layer was in its reduced state; whereas blue color at 2.0 V when PEDOT was in its reduced state and P(DTTP-co-EDOT) layer was in its oxidized state. At 0.2 V intermediate green state was observed. Maximum contrast (%ΔT) and switching time of the device were measured as 18% and 1 s at 615 nm. ECD has good environmental and redox stability.     

Low potential electrodeposition of high‐quality and freestanding poly(3‐(6‐bromohexyl)thiophene) films

High‐quality freestanding and conducting poly[3‐(6‐bromohexyl)thiophene] (PBHT) films with electrical conductivity of 20 S/cm were synthesized electrochemically by direct anodic oxidation of 3‐(6‐bromohexyl)thiophene (BHT) in boron trifluoride diethyl etherate (BFEE). The oxidation potential of BHT in pure BFEE was measured to be only 1.2 V versus saturated calomel electrode, SCE much lower than that determined in acetonitrile (ACN) (1.8 V vs SCE). The polymer films obtained from this media were very shiny and flexible and can be easily cut into various shapes. The structure and morphology of the polymer films were investigated by UV‐vis, infrared, ¹H‐NMR spectroscopy, thermal analysis, and scanning electron microscopy (SEM). All these results indicated that the terminal bromide did not have negative effect on the electrochemical polymerization of BHT. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of fluorescent methoxy poly(ethylene glycol)‐b‐Poly(ethyl cyanoacrylate)–2‐(N‐carbazolyl) ethyl methacrylate copolymer via living oxyanion‐initiated polymerization

The fluorescent amphiphilic block copolymer methoxy poly(ethylene glycol) (mPEG)‐b‐poly(ethyl cyanoacrylate) (PECA)–2‐(N‐carbazolyl) ethyl methacrylate (CzEMA) was synthesized via living oxyanion‐initiated polymerization. mPEG‐b‐PECA–CzEMA was characterized by gel permeation chromatography, ¹H‐NMR, and Fourier transform infrared spectroscopy. The results indicate that the polymerization was well controlled with a narrow molecular weight distribution. The mPEG‐b‐PECA–CzEMA nanoparticles prepared by nanoprecipitation techniques showed a narrow size distribution with an average diameter of less than 100 nm. The mPEG‐b‐PECA–CzEMA exhibited a strong carbazole fluorescence. Furthermore, it was found that the fluorescence intensity of mPEG‐b‐PECA–CzEMA was sensitive to a change in solvent. The results indicate that a subtle change in the state of the polymer micellar association may have altered the state of carbazole groups, which was responsible for the fluorescence emission. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of thiophene functionalized polystyrene copolymers and their electrochemical properties

Thiophene functionalized polystyrene samples (TFPS) were synthesized by atom transfer radical polymerization (ATRP) of styrene, followed by Suzuki coupling with 3‐thiophene (Th) boronic acid. Conducting graft polymer of TFPS with thiophene was achieved at 1.5 V in tetrabutylammonium tetrafluoroborate/dichloromethane (TBAFB/DM) by electrochemical methods. Spectroelectrochemical analysis of the resulting copolymers [P(TFPS‐co‐Th)] reflected electronic transitions at 449, 721 and 880 nm, revealing π ? π* transition, polaron and bipolaron band formation, respectively. We also successfully established the utilization of dual type complementary colored polymer electrochromic devices using P(TFPS‐co‐Th)/poly(3,4‐ethylenedioxythiophene (PEDOT) in sandwich configuration. The switching ability, stability and optical memory of the electrochromic device were investigated by UV–visible spectrophotometry and cyclic voltammetry. Device switches between brown and blue color with a switching time of 1.3 s were prepared with optical contrast (%ΔT) of 25 %. Copyright © 2005 Society of Chemical Industry     

Curing behaviors and thermal properties of benzoxazine and N,N′‐(2, 2, 4‐trimethylhexane‐1, 6‐diyl) dimaleimide blend

A blend of bisphenol‐A based benzoxazine (BA‐a)/N, N′‐(2, 2, 4‐Trimethylhexane‐1, 6‐diyl) dimaleimide (TBMI) with the ratio of 1:1 was prepared and its curing behaviors were studied by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR). The curing mechanism was proposed based on the semiquantitative analysis from FTIR spectra. The model compound was used to study the catalysis effect of BA‐a on the curing reaction of TBMI. It was found the curing reactions of BA‐a and TBMI not only proceeded simultaneously, but their coreactions also occurred. The research further indicated that negative oxygen ions from ring opening of benzoxazine mainly promoted the polymerization of maleimide groups, even though the amine group of benzoxazine had a positive effect on the reaction of maleimide groups. Besides, BA‐a and TBMI blends showed improved thermal properties based on the results from DMA and TGA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of N‐ and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]

Poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] was synthesized in an aqueous hydrochloric acid medium with a determined feed ratio by chemical oxidative polymerization. This polymer was used as a functional conducting polymer intermediate because of its side‐group reactivity. To synthesize the alkyl‐substituted copolymer, the initial copolymer was reacted with NaH to obtain the N‐ and O‐anionic copolymer after the reaction with octadecyl bromide to prepare the octadecyl‐substituted polymer. The microstructure of the obtained polymers was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray diffraction. The thermal behavior of the polymers was investigated by thermogravimetric analysis and differential scanning calorimetry. The morphology of obtained copolymers was studied by scanning electron microscopy. The cyclic voltammetry investigation showed the electroactivity of poly [aniline‐co‐N‐(2‐hydroxyethyl) aniline] and N and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]. The conductivities of the polymers were 5 × 10^?5 S/cm for poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] and 5 ×10^?7 S/cm for the octadecyl‐substituted copolymer. The conductivity measurements were performed with a four‐point probe method. The solubility of the initial copolymer in common organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylformamide was greater than polyaniline. The alkylated copolymer was mainly soluble in nonpolar solvents such as n‐hexane and cyclohexane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface modification of polythiophene and poly(3‐methyl thiophene) films by graft copolymerization

Polythiophene (PTH) and poly(3‐methyl thiophene) (PMT) films were electrochemically polymerized in an electrolyte solution of boron fluoride–ethyl ether. Ozone‐pretreated PTH and PMT films were subjected to UV‐light‐induced graft copolymerization with different monomers, including poly(ethylene glycol) monomethacrylate, acrylic acid, and glycidyl methacrylate. Surface grafting with the hydrophilic polymers gave rise to more hydrophilic PTH and PMT films. The structure and chemical composition of each copolymer surface were studied by X‐ray photoelectron spectroscopy. The surface grafting with the hydrophilic polymers resulted in a more hydrophilic PTH film. The dependence of the density of surface grafting and the conductivities of the grafted PTH and PMT films on the ozone pretreatment was also studied. A large amount of the grafted groups at the surface of the PTH and PMT films remained free for further surface modification and functionalization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Amphiphilic diblock copolymers poly(2‐hydroxyethylmethacrylate)‐b‐(N‐phenylmaleimide) and poly(2‐hydroxyethylmethacrylate)‐b‐(styrene) using the macroinitiator poly(HEMA)‐Cl by ATRP: Preparation,characterization, and thermal properties

In recent years, much attention has been given to the development of specialty polymers from useful materials. In this context, amphiphilic block copolymers were prepared by atom transfer radical polymerization (ATRP) of N‐phenylmaleimide (N‐PhMI) or styrene using a poly(2‐hydroxyethylmethacrylate)‐Cl macroinitiator/CuBr/bipyridine initiating system. The macroinitiator P(HEMA)‐Cl was directly prepared in toluene by reverse ATRP using BPO/FeCl₃ 6 H₂O/PPh₃ as initiating system. The microstructure of the block copolymers were characterized using FTIR, ¹H‐NMR, ¹³C‐NMR spectroscopic techniques and scanning electron microscopy (SEM). The thermal behavior was studied by differential scanning calorimetry (DSC), and thermogravimetry (TG). The theoretical number average molecular weight (M_n,th) was calculated from the feed capacity. The microphotographs of the film's surfaces show that the film's top surfaces were generally smooth. The TDT of the block copolymer P(HEMA)₈₀‐b‐P(N‐PhMI)₂₀ and P(HEMA)₉₀‐b‐P(St)₁₀ of about 290°C was also lower than that found for the macroi′nitiator poly(HEMA)‐Cl. The block copolymers exhibited only one T_g before thermal decomposition, which could be attributed to the low molar content of the N‐PhMI or St blocks respectively. This result also indicates that the phase behavior of the copolymers is predominately determined by the HEMA block. The curves reveal that the polymers show phase transition behavior of amorphous polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of poly(4‐diphenylaminostyrene)‐Poly(9‐vinylanthracene) binary block copolymer

Block copolymerization of plural types of monomers offers a new opportunity for the preparation of a variety of multifunctional polymers. Poly(4‐diphenylaminostyrene) (PDAS)‐poly(9‐vinylanthracene) (PVAN) binary block copolymer (PDAS‐PVAN) was synthesized by (living) anionic polymerization using the benzyllithium/N,N,N′,N′‐tetramethylethylenediamine system. The photoluminescence emission of PDAS‐PVAN was enhanced by the fluorescence resonance energy transfer from PDAS block to PVAN block in PDAS‐PVAN. The hole drift mobility of the copolymer was controllable by the amount of triphenylamino groups in the polymer chain. The optical and electrical properties of PDAS‐PVAN were adjustable through the polymer chain structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of the novel block copolymer poly(ε‐caprolactone)‐b‐poly(4‐vinyl pyridine) by the combination of coordination and controlled free‐radical polymerizations

A novel block copolymer, poly(ε‐caprolactone)‐b‐poly(4‐vinyl pyridine), was synthesized with a bifunctional initiator strategy. Poly(ε‐caprolactone) prepolymer with a 2,2,6,6‐tetramethylpiperidinyloxy (TEMPO) end group (PCL_T) was first obtained by coordination polymerization, which showed a controlled mechanism in the process. By means of ultraviolet spectroscopy and electron spin resonance spectroscopy, the TEMPO moiety was determined to be intact in the polymerization. The copolymers were then obtained by the controlled radical polymerization of 4‐vinyl pyridine in the presence of PCL_T. The desired block copolymers were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and NMR spectroscopy in detail. Also, the effects of the molecular weight and concentration of PCL_T on the copolymerization were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2280–2285, 2004     

Improvement of the conductivity,electroactivity, and redoxability of polythiophene by electropolymerization of thiophene in the presence of catalytic amount of 1‐(2‐pyrrolyl)‐2‐(2‐thienyl) ethylene (PTE)

The electropolymerization of thiophene in the presence of 1‐(2‐pyrrolyl)‐2‐(2‐thienyl) ethylene (PTE) was investigated. PTE was synthesized via Wittig reaction and by the addition of catalytic amount of PTE during the electropolymerization of thiophene, the conditions of electropolymerization of thiophene were modified. The cyclic votammograms of polythiophenes (PThs) in different conditions were obtained. The analysis of cyclic votammograms of PThs shows a considerable increase in the electroactivity and redoxability when the electropolymerization of thiophene in the presence of catalytic amount of PTE was performed. The presence of PTE during electropolymerization of thiophene leads to an increase in the rate of polymerization too. The cyclic voltammetry (CV) measurement of electron transfer ferro/ferricyanide redox system on different modified glassy carbon (GC) electrode has shown that the rate of charge transfer for PTh in the presence of PTE increased in comparison to pure PTh. The conductivity of obtained polymers was determined by electrochemical impedance spectroscopy (EIS) technique in 3.5% (w/v) NaCl solutions. The Zview(II) software was applied to the EIS to estimate the parameters of the proposed equivalent circuit, based on a physical model for the electrochemical behavior of coatings on GC. The R_ct value obtained for PTh is 7667 Ω cm². This value decreases in the presence of PTE to 4437 Ω cm². Thus, the new film has more conductivity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electropolymerization of a new 4‐(2,5‐Di‐2‐thiophen‐2‐yl‐pyrrol‐1‐yl)‐tetra substituted nickel phthalocyanine derivative

A new tetrakis 4‐(2,5‐di‐2‐thiophen‐2‐yl‐pyrrol‐1‐yl) substituted nickel phthalocyanine (NiPc‐SNS) was synthesized and characterized by elemental analysis, Fourier Transform Infrared (FT‐IR), and UV–vis spectroscopies. The electrochemical polymerization of this newly synthesized NiPc‐SNS was performed in dichloromethane (DCM)/tetrabutylammonium perchlorate (TBAP) solvent/electrolyte couple. An insoluble film was deposited on the electrode surface, both during repetitive cycling and constant potential electrolysis at 0.85 V. Resulting polymer film, P(NiPc‐SNS), was characterized utilizing UV–vis and FT‐IR spectroscopic techniques and its electrochemical behavior was investigated via cyclic voltammetry (CV). Spectroelectrochemical behavior of the polymer film on indium tin oxide (ITO) working electrode was investigated by recording the electronic absorption spectra, in situ, in monomer‐free electrolytic solution at different potentials and it is found that the P(NiPc‐SNS) film can be reversibly cycled between 0.0 and 1.1 V and exhibits electrochromic behavior; dark olive green in the neutral and dark blue in the oxidized states with a switching time of 1.98 s. Furthermore, the band gap of P(NiPc‐SNS) was calculated as 2.27 eV from the onset of π–π* transition of the conjugated backbone. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011