CONDUCTIVE COMPOSITES FROM POLYPYRROLE ELECTROPOLYMERIZED IN A POLYURETHANE MATRIX

In order to improve the mechanical properties of polypyrrole, composites were made by electropolymerizing polypyrrole in a polyurethane matrix. Polypyrrole/polyurethane (PPY/PU) composite films containing CLO_4^-, BF_4^- or CH_3-C_6H_4-SO_3^- counter ions were made in a variety of solvent systems and characterized by SEM, electronic conductivity, FTIR, and mechanical properties. Composite films showing much greater fiexibility than pure polypyrrole were obtained, but their electronic conductivities were substantially lower. Measured eonductivities ranged from 0.001 to 8 S/cm, tensile strengths from 44 to 592 psi, and elongation to failure from 3 to 70%.

Electro‑copolymerized film of ruthenium catalyst and redox mediator for electrocatalytic water oxidation

Electro-copolymerized film containing ruthenium complexes as electron-transfer(or redox)mediators and water-oxidation catalysts by an oxidative copolymerization method is presented.The addition of the redox mediator significantly improved the electrocatalytic water-oxidation activity and reduced the overpotential to 220 mV.The prepared electrode showed a water-oxidation catalytic rate constant kobs of 31.7 s^(-1)and an initial turnover frequency of 1.01 s^(-1)in 1000 s by potential electrolysis at 1.7 V applied bias vs NHE(normal hydrogen electrode).The kinetic isotope effect study suggests that the catalytic water oxidation reaction on the electrode surface occurs via a bimolecular coupling mechanism.

Electropolymerized films of redox-active ruthenium complexes for multistate near-infrared electrochromism,ion sensing,and information storage

This paper summarizes our recent progress on the preparations and applications of electropolymerized thin films of redox-active ruthenium complexes.Thin films of vinyl-functionalized diruthenium or ruthenium-amine conjugated complexes are prepared by reductive electropolymerization.The resulting films are useful for multistate near-infrared electrochromism,ion sensing,and mimicking flip-flop and flip-flap-flop logic gates.The oxidative electropolymerization of diruthenium complexes with two distal triarylamine units affords electropolymers with an alternating diruthenium and tetraphenylbenzidine structural unit.The applications of the resulting films in multistate near-infrared electrochromism and resistive memory are discussed.

In-situ electropolymerized bipolar organic cathode for stable and high-rate lithium-ion batteries

To address the dissolution issue and enhance the electrochemical performance of organic electrode materials,herein, a bipolar organic cathode was prepared by in-situ electropolymerization of amino-phenyl carbazole naphthalene diimide(APCNDI). APCNDI is composed of n-type 1,4,5,8-naphthalene tetracarboxylic diimide that stores Li cations and p-type carbazole groups which react with anions and serve as polymerization sites. Electropolymerization completely eliminated the dissolution problem of APCNDI, and the electropolymerized cathode demonstrated a bipolar reaction with excellent electrochemical performance, stable cycling performance with a capacity retention of 92 mA h g;after1000 cycles, and a superior rate performance of 72 mA h g;at 10 A g;. The bipolar feature and reactions of APCNDI were systematically investigated and verified by multiple characterization techniques. Our findings provide a novel strategy for the design and fabrication of electrodes for high-performance organic batteries.

Electropolymerized poly(Toluidine Blue)-modified carbon felt for highly sensitive amperometric determination of NADH in flow injection analysis

Poly（pheniothiazine） films were prepared on a porous carbon felt（CF） electrode surface by an electrooxidative polymerization of three phenothiazine derivatives（i.e.,Tthionine（TN）,Toluidine Blue（TB） and Methylene Blue（MB）） from 0.1 mol/L phosphate buffer solution（pH 7.0）.Among the three phenothiazies,the poly（TB） film-modified CF exhibited an excellent electrocatalytic activity for the oxidation of nicotinamide adenine dinucleotide reduced form（NADH） at ＋0.2 V vs.Ag/AgCl.The poly（TB） film-modified CF was successfully used as working electrode unit of highly sensitive amperometric flow-through detector for NADH.The peak currents（peak heights） were almost unchanged,irrespective of a carrier flow rate ranging from 2.0 to 4.1 mL/min,resulting in the measurement of NADH（ca.30 samples/hr） at 4.1 mL/min.The peak current responses of NADH showed linear relationship over the concentration range from 1 to 30 μmol/L（sensitivity：0.318 μA/（μmol/L）;correlation coefficient：0.997）.The lower detection limit was found to be 0.3 μmol/L（S/N = 3）.

Electrochemical Synthesis of Phenol-aniline Copolymerization Coating on 304 Stainless Steel Anodes and Coating Microstructure Analysis

Electrochemical copolymerization of phenol and aniline was achieved on 304 stainless steel anodes in neutral water solution with an electrolyte of Na2SO4O4. Compared with pit corrosion potential of different copolymer coatings, the best solution composition was 0.09 mol/L phenol and 0.01 mol/L aniline. Through infrared spectrum analysis, polyaniline structure was proved in phenol-aniline copolymer, as well as more side chains. Scanning electron microscope was used to analyze microstructure of copolymer coating, taking advantage of part solubility of phenol-aniline eopolymer in tetrahydrofuran, the bifurcate network structure was observed. The copolymer coating microstructure was summarized, compared with the performance of polyphenol coatings, the reasons of corrosion resistance enhancement with the addition of aniline in electropolymerization reaction was assumed as well.

Polyaniline Formed in Alkaline Solution─A New Luminous Material

Electropolymerization of aniline in KOH solution and properties of the polymer are studied by using in situ reflex ellipsometry, cyclic voltammetry and fluorescence spectroscopic method. The change patterns of ellipsometric parameters and the thickness of film in the process of electropolymerization are investigated. The complex refractive indices and the fluorescence spectra of PAN indicate that the PAN is a new kind of luminous material.

A selective voltammetric detection for dopamine using poly(gallic acid) film modified electrode

The electrochemistry behavior of dopamine was investigated by cyclic voltammetry and differential pulse voltammetry at a poly (gallic acid) film modified glassy carbon electrode.Two electrons and two protons participated in the diffusion-controlled electrocatalytic oxidation of dopamine with a diffusion coefficient of 2.186×10^(-5) cm^2/s.The interference of ascorbic acid with the determination of dopamine could be efficiently eliminated.This work provided a simple approach to selectively and sensitively de...

Electropolymerization of O-Phenylenediamine in an Ionic Liquid

Ionic liquid like 1-ethyl-3-methylimidazolium bromine ([EMIM]Br) has been used as electrolyte for the electropolymerization of O-phenylenediamine at glassy carbon electrode by cyclic voltammetry. It is found that poly (O-phenylenediamine) film modified electrode has favorable electrochemical activity in acid solution.

Electrochimical determination of uric acid, xanthine and hypoxanthine by poly(xylitol) modified glassy carbon electrode

The novel covalently modified glassy carbon electrode with poly(xylitol) was prepared using an electropolymerization technique for the simultaneous determination of uric acid(UA), xanthine(XA) and hypoxanthine(HX). This new electrode presents an excellent electrocatalytic activity towards the oxidation of UA, XA and HX by cyclic voltammetry(CV) method. The oxidation peaks of the three compounds were well defined and had enhanced the peak currents. The separation potentials of the oxidation peak potentials for UA-XA and XA-HX were 380 and 370 mV in CV, respectively. Using differential pulse voltammetry(DPV) method, the calibration curves in the ranges of 5-55, 1.3-75.3 and 4-59 μmol/L were obtained for HX, XA and UA, respectively. The lowest detection limits(S/N=3) were 4.5, 0.75 and 3.75 μmol/L for HX, XA and UA, respectively. The practical application of the modified electrode was demonstrated by the determination of UA, XA, HX in human urine samples.

HIGHLY SENSITIVE CATALASE ELECTRODE BASED ON POLYPYRROLE FILMS WITH MICROCONTAINERS

Highly sensitive catalase electrodes for sensing hydrogen peroxide have been fabricated based on polypyrrole films with microcontainers. The microcontainers have a cup-like morphology and are arranged in a density of 4000 units cm^-2. Catalase was immobilized into the polypyrrole films with microcontainers （Ppy-mc）, which were coated on a Pt substrate electrode. The catalase/Ppy-mc/Pt electrode showed linear response to hydrogen peroxide in the range of 0-18 mmol/L at a potential of-0.3 V （versus SCE）. Its sensitivity was measured to be approximately 3.64 μA （mmol/L） ^-1 cm^- 2, which is about two times that of the electrode fabricated from a flat Ppy film （catalase/Ppy-flat/Pt electrode）. The electrode is highly selective for hydrogen peroxide and its sensitivity is interfered by potential interferents such as ascorbic acid, urea and fructose. Furthermore, such catalase electrodes showed long-term storage stability of 15 days under dry conditions at 4℃.

EFFECT OF ULTRASONIC WAVE ON THE ELECTROPOLYMERIZATION OF PYRROLE

Electropolymerization of pyrrole under ultrasonic field at 20kHz was performed in a series of aqueous and propylene carbonate (PC) solutions. The ultrasonic wave with moderate intensity at the power of 44W, which is the power threshold of the ultrasonic generator used in this work to produce cavitation effect, enhance the conductivity and tensile strength of the polypyrrole films as prepared. However, too high intensity of the ultrasonic wave is harmful to the polymerization.

Synthesis of Novel Covalent-linked Linear Porphyrin-Thiophene Copolymers

Linear porphyrin-thiophene copolymers were synthesized by linking 5, 15-positions of porphyrin with tetrathiophene or bithiophene moieties for preparing conducting polymer. 2,8,12,18-tetraethyl-3,7,13,17-tetramethyl-5, 15-dithienylporphyrin4a (45.1%), 5, 15-di-bithienyl- 2,8,12,18-tetraethyl-3, 7, 13, 17-tetramethylporphyrin4b (61. 2%) and their metal complexes were also reported in high yields (>90%) as the monomers. 5, 15-di-bithienylporphyrin and its metal complexes could be polymerized by oxidation using FeCl3 as oxidant. However, 5,15-dithienylporphyrin and its metal complexes can not be polymerized by same reaction. Their polymers were synthesized by electrochemical oxidation on the gold-plate electrode. The structures of copolymers were identified by elemental analysis and IR spectra. And the conductivity of poly 5,15-di-bithienylporphyrin was measured to reach over 1.0× 10?6S/cm. Key words organic conductor - thienylporphyrin - porphyrin-thiophene copolymer - electropolymerization CLC number O 62 Foundation item: Supported by the National Natural Science Foundation of China (29872033, 20272046)Biography: CHEN Zhang-ping (1946-), male, Professor, research direction: porphyrin chemistry.

ELECTROPOLYMERIZATION OF ANILINE ON ZINC-ELECTROPLATED STEEL FROM NEUTRAL AQUEOUS MEDIUM BY SINGLE-STEP PROCESS

Polyaniline films were successfully synthesized on zinc-electroplated steel sheets in sodium salicylate (1mol·dm-3) aqueous medium. This one-step aniline electropolymerization process has been studied in this paper using different electrochemical techniques. And scanning electron microscopy (SEM) showed that the polymer coatings rapidly formed by either galvanostatic or potentiostatic mode performed compact and uniform in morphology. Potentiodynamic polarization was used to test the anticorrosion properties of this polymer.

Electrocatalytic Determination of Dopamine in the Presence of Ascorbic Acid by Poly-L-proline and Ferricyanide Compound Film Modified Electrode

A novel biosensor was fabricated by the electrochemical polymerization of poly-L-proline（P-LP） and ferricyanide（FC） to form a compound film on a glassy carbon electrode（GCE）. The compound film modified electrode（P-LP/FC/GCE） shows electrocatalytic activity toward dopamine（DA） in a phosphate buffer solution（PBS, pH = 4.0） with a diminution of the overpotential and an increase in peak current. P-LP/FC/GCE was used to study the electrocatalytic oxidation of DA and ascorbic acid（AA） by means of cyclic voltammetry（CV）, differential pulse voltammetry（DPV） and amperometric i-t curve techniques. The overlapping anodic peaks of DA and AA were resolved into two well-defined voltammetric peaks in CV and DPV with the potential differences of about 200 and 225 mV, respectively. The peak current of DA is linearly change with the concentration of DA in a range of 1 × 10^-7 to 1.14 × 10^-4 mol/L with the correlation coefficient of 0.9997. The detection limit is 4.4~10-8 mol/L（S/N=3）. P-LP/FC/GCE exhibited an excellent selectivity, sensibility and stability for the determination of DA, and can be applied to the determination of dopamine injections with satisfied results.

Conjugated microporous polymer membranes for chemical separations

Conjugated microporous polymers(CMPs) are a unique class of porous organic materials, which are constructed with π-conjugation structures leading to intrinsic micropores. The CMPs properties such as high surface area, intrinsic and rich micropores, interlocking and rigid structure, extensive π-conjugation and tunable band-gap, chemical and thermal stability, together with tailored functionalities, contribute to its abundant potential for application in fields such as photocatalysis, optoelectronics, energy storage, and chemical sensors. Recently, CMPs have gained importance in the field of membranes for chemical separation. In this review, we briefly discuss the historical development of CMPs, followed by a detailed description of the progress in state-of-the-art design, preparation, and application of CMPs in membranes. Additionally, we provide inference on the future prospects of CMPs as membranes.

Polymer Film Supported Bimetallic Au–Ag Catalysts for Electrocatalytic Oxidation of Ammonia Borane in Alkaline Media

Ammonia borane is widely used in most areas including fuel cell applications.The present paper describes electrochemical behavior of ammonia borane in alkaline media on the poly(p-aminophenol) film modified with Au and Ag bimetallic nanoparticles.The glassy carbon electrode was firstly covered with polymeric film electrochemically and then,Au,Ag,and Au–Ag nanoparticles were deposited on the polymeric film,respectively.The surface morphology and chemical composition of these electrodes were examined by scanning electron microscopy,transmission electron microscopy,electrochemical impedance spectroscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.It was found that alloyed Au–Ag bimetallic nanoparticles are formed.Electrochemical measurements indicate that the developed electrode modified by Au–Ag bimetallic nanoparticles exhibit the highest electrocatalytic activity for ammonia borane oxidation in alkaline media.The rotating disk electrode voltammetry demonstrates that the developed electrode can catalyze almost six-electron oxidation pathway of ammonia borane.Our results may be attractive for anode materials of ammonia borane fuel cells under alkaline conditions.

The Electrochemical Behaviour of PEDOT Film Electrosynthesized in Presence of Some Dopants

Electropolymerization and characterization of poly(3,4-ethylene dioxythiophene) (PEDOT) doped with functionalized single-walled carbon nanotubes (SWANTs) polyaminobenzene sulfonic acid (PABS) and different dopants were studied. It was fabricated by a simple oxidative electropolymerization method. The nanocomposite coatings have been prepared by using electrochemical methods from aqueous solutions, such that the components were deposited onto platinum electrode substrate. The morphology of composite films was analyzed by scanning electron microscopy (SEM). The electrochemical and physical properties of the resulting composites were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FT-IR) techniques in 0.1 M LiClO4 aqueous solutions. The value of specific electrochemical capacitance of the composite films is considerably higher than that of the pure polymers films. The improved properties of the electrodes were obtained by using these composite films. The dopant substances used were sodium dodecyl sulfate (SDS) and 1,2-Dihydroxy- benzene-3,5-disulfonic acid disodium salt hydrate (tiron).

Towards Ultrahigh Capacity and High Cycling Stability Lithium-Conducting Polymer Batteries by In Situ Construction of Nanostructured Porous Cathodes

Conducting polymers(CPs)have long been studied as cathode materials for lithium-ion batteries,but the low doping level(maximum:30–50%or even lower)and poor cycling stability limit their applications.Herein,we have developed a method of nanoporeconfined in situ electropolymerization to prepare nanostructured polythiophene-type porous cathodes,achieving significantly improved doping availability and long cycle life.It was verified that the nanosized polymer formed in situ and loose porous structure are conducive to the doping reaction and maintain high electrochemical stability.The constructed thieno[3,2-b]thiophene(TtTP)/active carbon cathode delivers an ultrahigh reversible capacity of 309.2 mAh g^(−1)(doping level up to 80.9%)along with an ultrahigh energy density of 1252.3 Wh Kg^(−1),and an ultrahigh rate capability(172.4 mAh g^(−1) at 30 A g^(−1)),which far exceed all the CPs and even all the p-type organic cathode materials reported.Moreover,an excellent long cycle life of 2000 cycles at 5 A g^(−1) is also revealed,which is a new record for CPs-based cathode materials in nonaqueous lithium-ion batteries.Our method provides an effective strategy to improve the doping level and cycling stability of CP-based cathode materials.

Constructing a lithiophilic polyaniline coating via in situ polymerization for dendrite-free lithium metal anode

Metallic lithium is regarded as one of the most promising electrode materials to break through the energy density bottleneck of current commercial lithium-ion batteries.However,the practical implementation of lithium metal anode is limited by the unstable electrode interface significantly,which directly induces a low Coulombic efficiency,short cycling lifespan,and dendritic lithium growth behavior.In this study,via in situ electropolymerization,lithiophilic and conformal polyaniline layer is developed to improve the initial lithium nucleation and plating process,reducing the interface charge transfer resistance and promoting uniform lithium plating/stripping behavior.Meanwhile,the polyaniline layer exhibits good adhesion to the substrate.As a result,the Li/Cu half cell delivers a high Coulombic efficiency of 99.1%for 400 cycles at 1.0 mA·cm^(−2)with polyaniline layer.In addition,long-term stable cycling at a current density of 1.0 mA·cm^(−2)for 1300 h has been achieved for lithium metal anode.This strategy provides a new perspective for the practical lithium metal batteries.