ELECTROCHEMICAL POLYMERIZATION OF ANILINE IN PHOSPHORIC ACID AND THE PROPERTIES OF POLYANILINE

The behavior of the electrochemical polymerization of aniline in a weak acid, phosphoric acid, is very similar to that in strong acids, i.e. its polymerization rate increases quickly with the electrolysis time. The FTIR spectra of polyaniline samples synthesized in phosphoric acid indicate that the counter ion H2PO4- is present in both the oxidized form and the reduced form of polyaniline. The counter ion plays an important role in adjusting the pH value at the electrode surface of polyaniline during the oxidation and reduction processes. As a result, a pair of redox peaks still appear in cyclic voltammograms of polyaniline in a solution of sodium sulfate of pH 5.5 and in a solution of NaH2PO4 of pH 7.0, respectively, at low potential scan rate; and the color of polyaniline film also changes with applied potential at pH 7.0. Thus, the pH region for the electrochemical activity and the electrochromism of polyaniline is extended to pH 5.5 for a solution of sodium sulfate and to pH 7.0 for a solution of NaH2PO4. The conductivity of polyaniline is 3.3 S cm-1, depending on the concentration of phosphoric acid used in the stage of polymerization of aniline. The result of elemental analysis of polyaniline is presented here.

ELECTROCHEMICAL POLYMERIZATION OF 5-CYANOINDOLE IN MIXED ELECTROLYTES OF BORON TRIFLUORIDE DIETHYL ETHERATE AND DIETHYL ETHER

High quality poly（5-cyanoindole） （P5CI） films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate （BFEE） and diethyl ether （EE） （by volume 1：1） ＋ 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide （DMSO） while partly soluble in tetrahydrofuran （THF） or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.

Properties of PAn/PVA Conducting Composite Film by Electrochemical Polymerization

The polyaniline (PAn)/poly(vinyl alcohol) (PVA) conductive composite film is synthesized with perchloric acid (HClO 4) as the dopant and oxidant in reaction system by electrochemical polymerization. The result shows that this composite film has very high conductive properties, the maximum value of conductivity reaches 0.173 S/cm at the concentration 0.75 mol. The influences of HClO 4 on the conductivity of the composite film are investigated.In addition,the electrode reaction progress is discussed with the result that obtained from SEM and FTIR analyzing.

Optical and Electrical Properties of Sensitized Polyaniline by Electrochemical Polymerization

To sensitize polyaniline with dyes by electrochemical polymerization, HClO 4 is employed as the dopant and oxidant, and the polyaniline with different sensitive properties is synthesized. The effect of sensitized emeraldine salt on the absorption spectrum is discussed in details. The maximum conductivity of sensitized films reaches 1.22 S/cm, and investigation on dye sensitizing of the polymer reveals that C.I. Direct Blue 71, C.I. Direct Blue 84, C.I. Direct Black 19 and CuPc-(COOH) 4 may enhance the photoconductivity of polyaniline greatly.

ELECTROCHEMICAL COPOLYMERIZATION OF 3-(4-FLUOROPHENYL)THIOPHENE AND 3-METHYLTHIOPHENE IN BORON TRIFLUORIDE DIETHYL ETHERATE

The copolymer poly（3-（4-fluorophenyl）thiophene-co-3-methylthiophene） was successfully prepared from mixtures of 3-（4-fluorophenyl）thiophene （FPT） and 3-methylthiophene （MET） via electrochemical oxidation in boron trifluoride diethyl etherate （BFEE） and its mixed electrolytes with acetonitrile （ACN）. The influence of monomer concentration ratios on the copolymerization was investigated by using linear sweep voltammetry and cyclic voltammetry. The structure and morphology of these copolymer films were elucidated by UV-Vis, infrared spectroscopy, elemental analysis, thermal analysis and scanning electron microscopy （SEM）, respectively. The results showed that the molar ratio of FPT and MeT units, when copolymer was electrodeposited from feed ratio of FPT：MeT = 1：2, was about 1.08：1. In addition, the introduction of ACN into BFEE has little effect on the properties of as-formed copolymers.

Investigation on the Electrochemical Polymerization of Catechol by Means of Rotating Ring-disk Electrode

The electrolysis of catechol was studied in the pH values of 1 to 10. The results from the rotating ring disk electrode (RRDE) experiments show that at low pH values, the electrochemical polymerization of catechol was performed by one step, and at higher pH values, the electrochemical polymerization of catechol was carried out by two steps, i.e . oxidation of catechol and followed by polymerization. The intermediates generated at the disk were detected at the ring electrode in the ring potential region of -0.2 to 0 V (vs. Ag/AgCl). One of reasons for the decrease in the ratio of i r to i d with increasing the ring potential is caused by formation of positively charged intermediates at the disk electrode. This ratio increases with increasing the rotation rate of the RRDE, which indicates that the intermediates are not stable. A shielding effect during polymerization of catechol was observed when the ring potential was set at 0.1 V (vs. Ag/AgCl). The electron spin resonance (ESR) of polycatechol shows that polycatechol possesses unpaired electrons. The images of polycatechol films synthesized at different conditions are described.

Electrochemical Polymerization of Brilliant Cresyl Blue and Properties of the Polymer

The electrochemical polymerization of brilliant cresyl blue (BCB) has been carried out using cyclic voltammetry in the potential region between -0.20 V and 1.15 V (vs. Ag/AgCl with saturated KCl solution). The electrolytic solution consisted of BCB (0.1 mol/L) and Na 2HPO 4 (0.2 mol/L) with pH 2.1. BCB can not be polymerized at pH<1. There are an anodic peak and a cathodic peak on the cyclic voltammogram of poly(BCB) at pH ≤4.3. Both peak potentials shift towards more negative with increasing pH value, and their peak currents decrease with increasing pH value. Poly(BCB) depicts a good electrochemical reversibility, fast charge transfer ability and stability in aqueous solutions with pH≤4.3. The visible spectrum, FTIR spectrum and Raman spectrum of poly(BCB) are different from those of BCB.

Electrochemical polymerization of 2,6-pyridinediamine and characterization of the resulting polymer

Electrochemical synthesis of poly（2,6-pyridinediamine） （PPa） in aqueous sodium hydroxide solution has been carried out by using cyclic voltammetry for the first time. The scanning electron microscopy （SEM） revealed the interpenetrating network structure of the as-prepared PPa film, which makes it possible that anions can be doped into the polymer in the oxidation process, and vice versa in the reduction process. The results from FT-IR spectrum provided a possible polymerization mechanism of 2,6- pyridinediamine.

Low Band Gap Polymers Synthesized by Electrochemical Polymerization for Electrochromic Devices

Two novel monomers, 10,13-bis（4-octyl-2-thienyl）-dibenzo[a,c]phenazine （OTBP） and 10,13-bis（4-octyl-2- thienyl）-dipyrido[3,2-a：2＇,3＇-c]phenazine （OTPP）, were synthesized. Electrochemical polymerization of OTPP and OTBP were carried out in acetonitrile/dichloromethane （ACN/DCM） solvent mixture containing tetra-n- butylammoniumhexafluorophosphate （TBAPF6）, and electrochromic properties of POTPP and POTBP are described. Furthermore, the effects of structural difference on electronic properties of electron acceptor units, electrochemical and electrochromic properties of two resulting polymers were examined. The results showed that the OTBP was polymerized at lower potential than OTPP, and this is because OTPP contains two more N atoms in electron acceptor unit and its electron withdrawing ability is stronger than that of OTBP. The UV-Vis-NIR spectra analysis revealed that the POTPP film has three absorption bands centered at 570 nm, 925 nm and 1581 nm, and the POTBP film has two absorptions at 566 nm and 1009 nm, respectively. The electrochromic properties indicated that the two polymer films exhibits reasonable optical contrasts and response time with low band gaps, defined as the onset of the absorption band at 570 nm for POTPP and the absorption band at 566 nm for POTBP, as 1.74 eV for POTPP and as 1.69 eV for POTBP.

ELECTROCHEMICAL POLYMERIZATION OF NANO-MICRO SHEAF/WIRE CONDUCTING POLYMER POLY[Ni(SALEN)]FOR ELECTROCHEMICAL ENERGY STORAGE SYSTEM

The polymer of complex [Ni（salen）], （N,N＇-ethylenebis （salicylideneaminato） nickel（U））, was prepared on graphite electrode by the route of linear sweep potential method. The nano-micro sheaf/wire structures of poly[Ni（salen）] have been obtained by adjusting the polymerization sweep rate of 5, 20 and 40 mV.s-1. The polymer prepared at 20 mV.s-1 had nanoscaled wire structure of ca. 100 nm in diameter. The good electrochemical reversibility of poly[Ni（salen）] was investigated by cyclic voltammetry and galvanostatic test in 1.0 mol/L Et3MeNBF4/acetonitrile solution. The initial specific gravimetric capacitance of poly[Ni（salen）] at the current density of 0.1 mA·cm-2 reached 270.2 F·g-1, however, the cycle stability needs to be improved.

Interdigital MnO_(2)/PEDOT Alternating Stacked Microelectrodes for High-Performance On-Chip Microsupercapacitor and Humidity Sensing

For microelectronic devices,the on-chip microsupercapacitors with facile construction and high performance,are attracting researchers'prior consideration due to their high compatibility with modern microsystems.Herein,we proposed interchanging interdigital Au-/MnO_(2)/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition.The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO_(2)and the conductive and electroactive layer of polyethylene dioxythiophene,hence providing excellent electron transport and diffusion pathways of electrolyte ions,resulting in increased pseudocapacitance of MnO_(2)and polyethylene dioxythiophene.The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm^(-2)(211.9 F cm^(-3)),an energy density of 3.8μWh cm^(-2)(at a voltage window of 0.8 V)and 5.1μWh cm^(-2)(at a voltage window of 1.0 V)with excellent rate capability(96.6%at 2 mA cm^(-2))and cycling performance of 85.3%retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm^(-2),higher than those of ever reported polyethylene dioxythiophene and MnO_(2)-based planar microsupercapacitors.Benefiting from the favorable morphology,bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors.This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.

Boosting the electrochemical performance and reliability of conducting polyme microelectrode via intermediate graphene for on-chip asymmetric micro-supercapacitor

High-performance anode is hurdle for on-chip planar microsupercapacitor(MSC).Polypyrrole(PPy)is a highly attractive pseudocapacitive material,but its low cycling stability,and low adhesion with current collector hinder its practicability.Herein we propose one-prong generic strategy to boost the cycling stability of PPy.For our strategy,the electrochemical deposition of multilayered reduced graphene oxide(rGO)on micropatterned Au is utilized,and the resultant rGO@Au pattern is then used for growing highly porous PPy nanostructures by facile electrochemical polymerization.The fabricated PPy anode on rGO@Au has quasi rectangular cyclic voltammetry curves up to-0.7 V and exceptional cycling stability,retaining82%of capacitance after 10,000 charge/discharge cycles in 2 M KCl electrolyte.The outstanding reliability of PPy on rGO@Au is due to the flexibility of rGO,accommodating structural pulverization and providing a promising background for the nucleation of highly porous nanostructure.Further,an all-polymer based asymmetric aqueous MSC(AMSC)is constructed with PPy anode and PEDOT cathode,which exhibited excellent electrochemical performance compared with conventional symmetric MSCs based on conducting polymers.The constructed AMSC delivered a maximum areal capacitance of 15.9 m F cm^-2(99.3 F cm^-3),high specific energy and power densities of 4.3μWh cm^-2(27.03 mWh cm^-3)and 0.36 W cm^-2(0.68 W cm^-3)at 1.4 V,respectively.The enhanced electrochemical performances can be illustrated by nucleation mechanism,in which surface topology of r GO generates a promising background for nucleation and electrochemical growth of nanoporous pseudocapacitive conducting polymers with superior interfacial contact and improved surface area.

THE ELECTROCHEMICAL PREPARATION OF POLYPHENOL WITH CONDUCTIBILITY

Polyphenol film deposited on platinum foil can continuously grow with time during the electrolysis of a phenol solution consisting of 0.1 mol L-1 phenol, 3 mol L-1 NaOH and 0.5 mol L-1 Na2SO4, as has been proved by the methods of sweep potential, constant potential and constant current, and visible spectra during the electrolysis of phenol. A polyphenol film with thickness of 0.11 mm was obtained by the electrolysis of phenol at a constant potential of 0.70 V (versus Ag/AgCl with saturated KCl solution). Polyphenol film is inactive and stable in 2 mol L-1 H2SO4 solution, neutral solution and 3 mol L-1 NaOH solution and in the potential range between -0.95 and 1.35 V. The usable potential range is dependent on the pH value. Polyphenol has an ESR signal with a g factor of 2.0049. The conductivity of polyphenol is 1.2 x 10(-4) S cm(-1). In the solution of polyphenol dissolved in DMSO, the mobility of polyphenol anions is 8 x 10(-9) m(2) s(-1) V-1 at 20degreesC.

ELECTROCHEMICAL SYNTHESIS AND PROPERTIES OF POLY(AZURE B)

A blue poly(azure B) film has been synthesized using repeated potential cycling between -0.25 and 1.10 V (versus SCE). The electrolytic solution consisted of 2.5 mmol dm(-3) azure B, 0.5 mol dm(-3) NaCl and 0.2 mol dm(-3) NaH2PO4 at the pH range of 2.0 to 11.0. The in situ visible spectrum during electrolysis of azure B shows that the intensity at 740 nm peak increases with increasing numbers of potential cycles, which is attributable to the formation of poly(azure B). The wavelength of its corresponding absorption peak is 98 nm longer than that of azure B. The polymerization rate is strongly affected by pH values. The anodic peak potential and cathodic peak potential of the poly(azure B) in a solution of pH 3.0 are not affected by increasing the scan rate from 25 to 600 mV s(-1). Poly(azure B) has good electrochemical reversibility and fast charge transfer characteristic in the pH range of 2.0 and 11.0. The conductivity of poly(azure B) is 1.5 x 10(-4) S cm(-1) According to the differences between FTIR spectra of poly(azure B) and azure B, an electrochemical polymerization mechanism of azure B is proposed in this paper.

ELECTRONIC EFFECTS OF POLYFLUORINATED SUBSTITUENTS ON THE POLYMERIZATION AND THE PROPERTIES OF POLYTHIOPHENES

Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes.

Ordered Nafion ionomers decorated polypyrrole nanowires for advanced electrochemical applications

Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report the electrochemical fabrication of ordered Nafion？ionomers decorated polypyrrole nanowires to construct the ordered proton-migration channels. Based on the electrostatic interaction between Nafion？ionomers and the polymer intermediate, ordered Nafion？ionomers decorated polypyrrole nanowires could be fabricated via chronoamperometry with varying contents of Nafionionomers. The morphologies, charge-storage performances, electron conductivity and proton conductivity of the composites are investigated by scanning electron microscopy, cyclic-voltammetry, galvanostatic charge–discharge measurement and electrochemical impedance spectroscopy. With the modification effect of Nafionionomers on polypyrrole nanowires, the composite shows greater ordered structure relative to another without Nafion？ionomers and the electrochemical performances change with the content of Nafion？ionomers.The composite could achieve a high specific capacitance of 356 F/g at 1 A/g with a 0.62-fold enhancement compared to polypyrrole nanowires without Nafion？ionomers. It also displays a superior electrical conductivity of 49 S/cm and a quite high proton conductivity of 0.014 S/cm at working conditions of fuel cells, which are associated with the requirements of fuel cells and have the potential to be the electrode material for a large range of electrochemical energy conversion devices.

Two-dimensional polymer-based nanosheets for electrochemical energy storage and conversion

Over the past decades, two-dimensional（2D） nanomaterials possessing planar layered architecture and unique electronic structures have been being quickly developed, due to their wide potential application in the fields of chemistry, physics, and materials science. As a new family of 2D nanomaterials, 2D polymerbased nanosheets, featuring excellent characters, such as tunable framework structures, light weight, flexibility, high specific surface, and good semiconducting properties, have been emerging as one kind of promising functional materials for optoelectronics, gas separation, catalysis and sensing, etc. In this review, the recent progress in synthetic approach and characterization of 2D polymer-based nanosheets were summarized, and their current advances in electrochemical energy storage and conversion including second batteries, supercapacitors, oxygen reduction and hydrogen evolution were discussed systematically.

Electrode Modifications for Polymer Light-Emitting Electrochemical Cells

The influence of different modification methods on the surface properties of indium-tin-oxide (ITO) electrodes were investigated by measurements of chemical composition,surface roughness,sheet resistance,contact angle and surface free energy.Experimental results demonstrate that oxygen plasma treatment more effectively optimizes the surface properties of ITO electrodes compared with the other treatments.Furthermore,the polymer light-emitting electrochemical cells (PLECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized.It is found that oxygen plasma treatment on the ITO electrode enhances injection current,luminance and efficiency,thereby improves the device characteristics of the PLECs.

Poly(4,4＇-bis(thien-2-yl)azobenzene-co-3-hexylthiophene)： Synthesis and Optical/Electrochemical Properties

A conjugated polymer of poly（4,4＇-bis（thien-2-yl）azobenzene-co-3-hexylthiophene）（PTAB-H）, bearing azo group in main chain and soluble in THF, chloroform, was synthesized through FeCl3 oxidation copolymerization with 3-hexylthiophene, and the monomer of 4,4＇-bis（thien-2-yl）azobenzene was synthesized by Sandmeyer reaction and Suzuki reaction. The UV-Vis spectra of PTAB-H reveal that azo group in the main chain can extend the absorption and lower the band gap. The fluorescent spectra, photoluminescence（PL） spectra, cyclic voltammetry（CV） of PTAB-H were recorded.The gel permeation chromatography（GPC）, thermogravimetry analysis（TGA）, and differential scanning calorimetry（DSC） measurements indicated that the molecular weight Mn, Mw and polydispersity indices（PDI） of the polymer are 10876 g/mol, 22338 g/mol and 2.05 respectively and the temperature of 5% weight-loss is 224.6 ℃. No glass transition and crystallization melting peak was observed in the temperature range from 30 ℃ to 400 ℃.

Studies on the Coordination Polymer of Copper El ectropol yurushiol

The coordination polymer of copper electropolyurushiol(EPU-Cu^(2+)) was obtained by the reaction of copper chloride with electropolyurushiol (EPU) in an isopropyl alcohol solution. The properties of EPU-Cu^(2+) were studied by means of ESR, FTIR, XPS, DMTA and TG-DTA. The results of AES show that the content of Cu^(2+) was 8.63%. The electric resistances of EPU-Cu^(2+) and EPU were determined to be 9, 37×10^(10) Ω and 7.90×10^(10) Ω respectively. It was also ascertained that in EPU-Cu^(2+) each Cu^(2+) is coordinated with two units hydroxyl in EPU, making the EPU-Cu^(2+) cross-link further. As a result, the title polymer exhibits an insolubility in most of organic solutions, a higher glass transition temperature and thermal resistance.