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.     

A soluble conducting polymer: 1-Phenyl-2,5-di(2-thienyl)-1H-pyrrole and its electrochromic application

A thiophene-functionalized monomer 1-phenyl-2,5-di(2-thienyl)-1H-pyrrole (PTP) was synthesized. The chemical polymerization of PTP (CPTP) was realized by using FeCl₃ as the oxidant. The structures of both the monomer and the soluble polymer (CPTP) were investigated by Nuclear Magnetic Resonance (¹H and ¹³C NMR) and Fourier Transform Infrared (FTIR). The average molecular weight of the chemically synthesized polymer was determined by gel permeation chromatography (GPC) as Mn = 7.2 × 10³. The electrochemical oxidative polymerization of PTP was carried out via constant-potential electrolysis. Characterizations of the resulting polymer were done by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-vis Spectroscopy. The conductivity of sample was measured by four-probe technique. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. Spectroelectrochemical analysis of P(PTP) revealed electronic transitions at 413, 577 and 884 nm corresponding to π-π^* transition, polaron, and bipolaron band formations, respectively. Kinetic studies evaluated the switching ability of the P(PTP); the percent transmittance T% was found as 27%. The homopolymer of PTP was used to construct dual-type polymer electrochromic devices (ECDs) against poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated.     

Orange to black electrochromic behaviour in poly(2-(2-thienyl)-1H-pyrrole) thin films

We have studied an electrochromic precursor, 2-(2-thienyl)-1H-pyrrole (1), using two improved procedures of the Trofimov reaction. Optimised stereochemical calculations at the B3LYP/6-311G* level showed almost equal s-cis and s-trans conformational populations in 1 with marked out-of-plane deviations of ca. 30°. Model calculations suggest that the predominant rotational conformation in undoped poly(1) would be s-trans with the essential out-of-plane deviations around the all three interheterocyclic bonds of ca. 25-30°. Monomer 1 exhibited two irreversible oxidation processes at +0.86 and +1.3 V corresponding to the oxidation of the pyrrole and thiophene rings, respectively. Orange to black electrochromic behaviour was found in ClO₄⁻ doped poly(1) thin films with colouring and bleaching times of 1.8 and 1.3 s, respectively. The colouration efficiency during the bleaching process was 233 cm²/C. The optical contrast at 450 nm was 19% and in the near-IR was 36%. The band-gap of poly(1) (1.6-1.7 eV) was found to be significantly lower than that of polypyrrole (2.85 eV) and polythiophene (2.3 eV) as a consequence of increased electron delocalisation in the system. Important differences in the morphology of doped and dedoped poly(1) films were observed by atomic-force microscopy (AFM). Doped poly(1) films showed a granular morphology with primary particles of 45-60 nm in size and an average surface roughness of 3.5 nm. On the other hand, dedoped poly(1) films showed interconnected aggregates of 65-90 nm in size as a consequence of particle fusion, with a surface roughness of 9.2 nm. In summary, poly(1) is a promising material for emerging flexible electrochromic devices such as displays and variable optical attenuators.     

The reactivity towards the benzoyloxy radical of 1,4-bis(2-methylstyryl)benzene

It has been found that 1,4-bis(2-methylstyryl)benzene (MSB) is 520 times as effective as methyl methacrylate in capturing the benzoyloxy radicals generated at 60°C by dissociation of benzoyl peroxide. This result has been obtained from examinations of the end groups in samples of poly(methyl methacrylate) prepared using benzoyl peroxide as initiator in the presence of MSB at low concentrations.     

Synthesis, characterization and electrochromic properties of a near infrared active conducting polymer of 1,4-di(selenophen-2-yl)-benzene

A novel selenophene-based monomer, 1,4-di(selenophen-2-yl)-benzene (DSB), was synthesized via Stille coupling reaction of 1,4-dibromobenzene and tributyl(2-selenophenyl)stannane. Conducting polymer (PDSB) was prepared electrochemically in the presence of tetrabutylammonium hexafluorophosphate (TBAPF₆) as the supporting electrolyte in dichloromethane (DCM). The resulting conducting polymer was characterized by Cyclic Voltammetry, Fourier Transform Infrared and Ultraviolet-visible spectroscopy. Spectroelectrochemistry analysis and kinetic studies of PDSB revealed a π-π^∗ transition at 340 nm with a striking and rapid (0.6 s) transmittance change (35%), at near infrared region (1250 nm), indicating that PDSB is a very suitable near infrared electrochromic material.     

Synthesis and characterization of poly(N-(2-(thiophen-3-yl)methylcarbonyloxyethyl)maleimide) and its spectroelectrochemical properties

A new monomer; N-(2-(thiophen-3-yl)methylcarbonyloxyethyl) maleimide (NMT) was synthesized. The chemical structure of the monomer was characterized by Nuclear Magnetic Resonance (¹H-NMR) and Fourier Transform Infrared (FTIR) Spectroscopy. Electrochemical polymerization of NMT was performed in acetonitrile (AN)/borontrifloride ethylether (BFEE) solvent mixture (1:1, v/v) where tetrabutylammonium tetrafluoroborate (TBAFB) was utilized as the supporting electrolyte. The resulting conducting polymer was characterized by Fourier Transform Infrared (FTIR) Spectroscopy, thermal analyses and Scanning Electron Microscopy (SEM). Electrical conductivity was measured by the four-probe technique. The spectroelectrochemical behavior and switching ability of P(NMT) film were investigated by UV–Vis spectrophotometry. P(NMT) revealed color changes between yellow and blue in the reduced and oxidized states respectively.     

Synthesis, characterization, and properties of poly(ethylene terephthalate)/poly(1,4-butylene succinate) block copolymers

Reactive blending at 290 °C of a series of mixtures of poly(ethylene terephthalate) (PET) and poly(1,4-butylene succinate) (PBS) led to the formation of block PET/PBS copolyesters. The block lengths of the resulting copolymers decreased with the severity of the treatment. Copolyesters with PET/PBS molar compositions of 90/10, 80/20, 70/30, and 50/50 were prepared by this method and their composition and microstructure were characterized by ¹H and ¹³C NMR, respectively. The T_g, T_m, and crystallinity of the copolymers decreased as the content in PBS and the degree of randomness increased. The elastic modulus and tensile strength of the copolymers decreased with the content of PBS, whereas, on the contrary, the elongation at break increased. The PET/PBS copolymers exhibited a pronounced hydrolytic degradability, which increased with the content in 1,4-butylene succinic units. Hydrolysis mainly occurred on the aliphatic ester groups.     

Thermal behavior of 1,4-bis(4-trimellitimido-2-trifluoromethyl phenoxy)benzene (DIDA) solvated with polar organic solvents and properties of DIDA-based poly(amide-imide)s

Fluorinated diimide-dicarboxylic acid (DIDA, Code: IV), 1,4-bis(4-trimellitimido-2-trifluoromethylphenoxy) benzene, synthesized by reacting 1,4-bis(4-amino-2-trifluoromethyl phenoxy)benzene (I) with trimellitic anhydride in polar solvents (PSv), was found to crystallize easily in amide-type solvents, such as N-methyl-2-pyrrolidinone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), or 1,3-dimethyl-2-imidazolidinone (DMI) media, to form a series of stable crystalline solvates (III_(NMP), III_(DMAc), III_DMF), III_(DMI)) containing a certain quantity of crystalline solvent. The solvates III_(PSv) were characterized and proven by DSC, TGA, and X-ray analysis. The decomposition point temperature (T_d) was different with the type of polar solvents in III_(PSv). Elemental analysis and NMR showed that most of the III_(PSv) were formed from IV and polar solvents in the ratio of 1:2, and the solvation processes were found to be reversible. Furthermore, a series of soluble fluorinated poly(amide-imide)s (VI_a-h) were synthesized from reacting either the NMP-solvates III_(NMP) or dry/non-solvates IV with an equivalent amount of diamines by direct polycondensation using triphenyl phosphate and pyridine as condensing agents. Thermal and mechanical properties of the fluorinated VI_a-h were measured, and compared with counterparts of non-fluorinated PAI's (Code: VI′s). In comparison, the fluorinated VI_a-h poly(amide-imide)s exhibited better solubility, tensile, and thermal properties than the non-fluorinated VI′s.     

Electrosynthesis of poly(neutral red) incorporated with ferrocenesulfonic acid

The electrochemical oxidation of neutral red in 0.5 mol dm⁻³ sulfuric acid and 0.2 mol dm⁻³ ferrocenesulfonic acid solution was carried out using repeated potential cycling between −0.20 and 1.40 V (versus SCE). The polymer film was electrochemically deposited on a platinum anode and had an electrochemical activity in the solution of 0.5 mol dm⁻³ Na₂SO₄ with pH ≤ 7.0. The result from the X-ray photoelectron spectroscopy (XPS) experiment shows that the anions can be doped into the polymer film during the electrochemical polymerization reaction of neutral red. The scanning electron microscopy (SEM) micrograph shows that the surface of the resulting polymer film formed on the platinum foil is covered with a compact surface consisting of micro fibers. The visible spectrum and infrared spectrum (IR) of the polymer are different from those of the corresponding monomer. A possible chemical structure of the resulting polymer was also proposed.     

N,N’-二(2-羟丙基)哌嗪的合成及其在烟气脱硫工艺中的应用

利用无水哌嗪和环氧丙烷合成了N,N’-二(2-羟丙基)哌嗪(HPP),利用红外光谱对其进行了表征,利用滴定法计算出HPP的共轭酸的pKa1和pKa2值,通过热重分析仪研究了HPP的半盐溶液与SO2的反应行为和SO42-在湿法烟气脱硫中对HPP挥发损失的影响。结果表明,HPP的合成反应是按照反应物的化学计量比进行的,且工艺过程简单,得到的产物纯度较高。HPP的共轭酸的pKa1和pKa2分别为3.8和8.2。SO42-能够有效的抑制HPP的挥发,可以作为烟气脱硫工艺中HPP半盐溶液的阴离子。     

Star-like polyaniline prepared from octa(aminophenyl) silsesquioxane: Enhanced electrochromic contrast and electrochemical stability

We report the structures, electrochemical and electrochromic properties of organic-inorganic hybrid polymers prepared via copolymerization of octa(aminophenyl) silsesquioxane and aniline. Compared with homopolyaniline (PANI), this class of novel materials exhibits much greater thermodynamic penetrability in solution, as detected using static and dynamic light scattering, suggesting that they have a star-like molecular geometry. Due to their star-like geometry, in solid state the copolymers (POSS-PANI) exhibit a loosely packed structure with relatively low crystallinity, as evidenced by X-ray and TEM characterization, and hence relatively high ionic conductivity. Cyclic voltammetric studies show that POSS-PANI undergoes similar electrochemical reactions to that of PANI but its loosely packed structure allows slightly faster cation diffusion. Spectro-electrochemical studies show a ∼40% enhancement in electrochromic contrast brought by tethering PANI onto POSS, which can be attributed to more accessible doping sites in POSS-PANI. Furthermore, the electrochemical stability of POSS-PANI is also significantly improved over that of PANI. Infrared spectroscopic measurements indicate that the formation of electrochemically inactive quinonediimine is retarded in POSS-PANI possibly due to the increased conformation freedom of the dopant anions.     

Preparation and properties of poly(amideether-imide)s derived from 1,4-bis(4-aminophenoxy)benzene,trimellitic anhydride,and various aromatic diamines

An imide ring containing dicarboxylic acid, 1,4-bis(4-trimellitimidophenoxy)benzene (III), was prepared by the condensation of 1,4-bis(4-aminophenoxy)benzene and trimellitic anhydride. A series of new poly(amide-ether-imide)s were prepared by the direct polycondensation of diimide-diacid III with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents inN-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. The highest inherent viscosity value of a poly(amide-ether-imide) obtained was 1.78 dL/g (inN,N-dimethylacetamide, DMAc, at 30 °C). Flexible films with excellent tensile properties were cast from DMAc solutions. Glass transition temperatures of these poly(amide-ether-imide)s were recorded in the range of 248–297 C. These polymers do not show obvious weight loss before 400°C; the decomposition temperatures at which 10% weight loss in nitrogen and in air were observed for these poly(amide-ether-imide)s in the range of 521–564°C and 501–539°C, respectively. The polymers derived fromp-phenylenediamine or the diamines containing 1,4-bisphenoxy units exhibited a higher degree of crystallinity and higher initial decomposition temperatures but poor solubility in organic solvents.     

Synthesis and characterization of soluble poly(N-heptyl indole)

In view of preparing soluble polyindole, indole was N-alkylated using bromoheptane and polymerized to poly(N-heptyl indole) which is soluble in common organic solvents. This process is being reported for the first time. Poly(N-heptyl indole) was characterized by spectral, thermal methods and it shows photoluminescence in liquid state.     

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.     

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     

1，4-双（对氟苯甲酰）苯及其聚合物的合成

以二硫化碳为溶剂、无水三氯化铝作催化剂、对苯二甲酰氯与氟苯为反应原料，在20℃利用Friedel-crafts酰基化反应合成了产率为76．7％、纯度为99．758％的1，4-双（对氟苯甲酰）苯（P，P-BFB）。经IR、^1HNMR和MS光谱对其结构分析，确定为P，P-BFB。以二苯砜为溶剂，在无水碳酸钾／碳酸钠的催化下，以P，P-BFB为单体与对苯二酚进行亲核取代反应合成了特性粘度为0．87的聚醚醚酮酮（PEEKK）。通过IR、DSC、TG和XRD对其结构与性能进行了表征，确定其结构为PEEKK；TG测试表明在氮气气氛下开始分解温度为557℃，且到1200℃时也没分解完全；DSC和XRD衍射图表明其为半晶态聚合物，且由DSC曲线可知其熔点Tm为367℃。     

Enhancing electrochromic and kinetic properties of poly(2,3-bis(4-tert-butylphenyl)-5,8-di(1H-pyrrol-2-yl) quinoxaline) by copolymerization

Electrochemical copolymerization was utilized to combine several properties into a single material in order to obtain a highly stable polymer with a low band gap to meet the requirements for color variation. In that sense, two new donor acceptor type electrochromic copolymers of 2,3-bis(4-tert-butylphenyl)-5,8-di(1H-pyrrol-2-yl) quinoxaline (TBPPQ) with bis(3,4-ethylenedioxythiophene) (BiEDOT) and with 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-dodecyl-2H-benzo [1,2,3] triazole (BEBT) were synthesized by electrochemical polymerization. Polymers revealed multicolor electrochromic properties with distinct accessible states and low operation potentials. Electrochromic and kinetic properties of polymers were investigated using cyclic voltammetry (CV) and in situ UV-vis-NIR spectroscopy.     

Synthesis and characterization of poly(1,4-dihydroxyanthraquinone terephthalate)

A novel polymeric dye containing an anthraquinone ring was prepared by solution polycondensation. The molecule geometry was fully optimized on the basis of the AM1 method. The hydrogen bond was formed and retained coplanarity in the molecular structure. In its UV spectrum, a large hypsochromic shift and a hypochromic effect were observed due to polyesterification. The polymeric dye was also characterized by means of IR and TG. Its thermal degradation mechanism was elucidated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2246–2248, 2001     

1,4-二(溴甲基)-2-氟苯的合成工艺改进

以对二甲苯为原料,经硝化、还原、重氮化、溴代4步反应得到标题化合物。其中溴代反应中,1,4-二甲基-2-氟苯在偶氮二异丁腈(AIBN)引发下与N-溴代丁二酰亚胺(NBS)发生自由基反应。总收率达到30%,其结构经1HNMR和GC/MS确证。     

9,9-双（甲氧基甲基）芴的合成及其应用研究

9,9-双（甲氧基甲基）芴（BMMF）的合成分两步进行：首先,在乙醇钠催化剂的作用下,芴与多聚甲醛反应合成了中间体9,9-双（羟甲基）芴（BHMF）,然后以四丁基溴化铵（TBAB）为相转移催化剂,再与氯甲烷发生烷基化反应合成了9,9-双甲氧基甲基芴。用9,9-双（羟甲基）芴作外给电子体进行了丙烯聚合应用,实验结果表明：9,9-双（甲氧甲基）芴（BMMF）是聚丙烯Ziegler-Natta催化体系较好的外给电子体。