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The corrosion protection of emeraldine base (EB) on mild steel in the artificial defect exposed to 1 wt% NaCl solution was studied using in situ optical microscope and scanning electron microscopy (SEM). The EB coating displayed good corrosion protection on the exposed bare steel, which was difficult to understand by traditional anodic protection mechanism or inhibitory protection mechanism, or cathodic protection mechanism, since steel usually cannot be passivated in brine, and EB coating cannot release inhibitory anions to protect exposed bare steel, and further, the galvanic coupling measurement demonstrates that EB cannot provide cathodic protection to exposed bare steel. The importance of dissolved oxygen diffusion caused by EB in corrosion protection was disclosed in this paper, a related protection model was therefore proposed, which was qualitatively verified by corresponding electrochemical measurements.

A new approach for the synthesis of polyaniline nanofibers under pseudo-high dilute conditions in aqueous system has been developed. High yield nanoscale polyaniline fibers with 18-110 nm in diameter are readily prepared by a high aniline concentration 0.4 M oxidation polymerization using ammonium persulfate (APS) as an oxidant in the presence of hydrochloric acid (HCl), perchloric acid (HClO4), (1S)-(+)-10-camphorsulfonic acid (CSA), acidic phosphate PAEG120 (PA120) and sulfuric acid (H2SO4) as the dopants. The novel pathway always produces polyaniline nanofibers of tunable diameters, high conductivity (from 10(0) to 10(1) S/cm) and crystallinity.

Ferrocenesulfonic acid (FSA) was oxidized by iodine (I2) and then used as dopant for polyaniline emeraldine base. The resulted polyaniline showed an electrical conductivity of 4.50 × 10−2 S/cm and a ferromagnetic interaction with a positive Weiss constant of 15 K, the magnetic behavior is attributed to the ferromagnetic coupling between ferrocenium cations in the counter-ions along the polyaniline chain.

A new iridium complex was synthesized and demonstrated a saturated red light emission in organic light-emitting diodes (OLEDs). The maximum brightness of 2800 cd/m 2 and the external quantum efficiency of 5.5% were achieved in multilayer OLEDs. The peak wavelength of the emission was found to be at 677 nm with the Commission Internationale de l’Eclairage (CIE) coordinates of (0.71, 0.27).

A series of polyfluorene derivatives endcapped by 0.1–2 mol% 1,8-naphthalimide dye were synthesized by Yamamoto coupling reaction. The resulting polymers show the promising electroluminescence (EL) performance with emission predominantly from the 1,8-naphthalimide unit due to energy transfer and charge trapping from polyfluorene backbone to 1,8-naphthalimide dye. Single-layer devices were fabricated with a device configuration of ITO/PEDOT/polymer/Ca/Al. Among all the devices tested, the device of NFP50 exhibited the current efficiency of 7.40 cd/A, the power efficiency of 2.89 lm/W and the maximum brightness of 19280 cd/m 2 , about 30 times more efficient than that of polyfluorene without endcapping groups.

Two polyfluorenes containing 1,8-Naphthalimide units were synthesized by Yamamoto polycondensation reaction. The 1,8-naphthalimide moieties act as both electron and hole trap in the resulting polymers, leading to the EL spectra different from the PL spectra in film. White electroluminescence with a maximum brightness of 11100 cd/m2, an external quantum efficiency of 2.0% and CIE coordinates of (0.26, 0.36) has been realized through partial energy transfer from polyfluorene to 1,8-naphthalimide moieties.

A novel series of emitting aluminum complexes containing two 8-hydroxyquinoline ligands (q) and a phenolato ligand (p) were synthesized and characterized. Double layer organic light-emitting diodes (OLEDs) were fabricated using these complexes as luminescent layers, and strong electroluminescence (EL) was observed. It was found that their emitting wavelengths were mainly determined by the first ligands (q). Cyclic voltammograms revealed a partially irreversible n-doping process and indicated that these complexes show excellent electron-transporting ability.

Photoluminescence (PL) quantum efficiency is a key issue in designing successful light-emitting polymer systems. Exciton relaxation is strongly affected by exciton quenching at nonradiative trapping centers and the formation of excimers. These factors reduce the PL quantum yield of light-emitting polymers. In this work, we have systematically investigated the effects of exciton confinement on the PL quantum yield of an oligomer, polymer, and alternating block copolymer (ABC) PPV system. Time-resolved and temperature-dependent luminescence studies have been performed. The ABC design effectively confine photoexcitations within the chromophores, preventing exciton migration and excimer formation. An unusually high (PL) quantum yield (above 90%) in the solid state is reported for the alternating block copolymer PPV, as compared to that of ∼30% of the polymer and oligomer model compounds.

By the method of FT-IR spectra, the six-member ring doping structure has been confirmed in sulfonated polyaniline for the first time. The six-member ring self-doping structure is composed of the sulfonic group and the imine group in the ortho position of the SPAn backbone. The influence of different acid, alkaline and salt on the ring doping structure has been studied by the quantitative spectra analysis technique. Because the ring structure is a stable structure in energy, it is difficult for inorganic salt, dilute acid and dilute alkaline to break it up, as the result the DC conductivity is independent of pH value in the period of 1

Using transmission electron microscope (TEM), the fractal structures have been found both in the colloid aggregates and in the colloidal particles of highly sulfonated polyaniline. In the present paper, the concept and mathematics model of fractal have been introduced into conjugated polymer. The colloid aggregates appear as an open dendriform structure with fractal dimension 1.43 and its growing process can be simulated by the Diffusion Limited Cluster Aggregate (DLCA) model. The simulated pattern by computer and the theoretic fractal dimension are consistent with the experimental results. Since the colloidal particle is generated in the evenness field formed by the dispersion media, the screening effect has been weakened and the colloidal particle is a spherical structure with fractal dimension 1.86, which is denser than colloid aggregates. The Random Rain (RR) model can be applied here and the simulation pattern and fractal dimension are coincident with the experiment results. So the system can be accounted as multi-fractals structure.

Polyaniline (PAn) with different molecular weight was prepared by adding organic solvents such as acetone, ethanol or THF into the polymerization mixture. Open-circuit potential measurements showed that the polymerization rate was lowered by the addition of the organic solvent. Spectral studies showed that PAn intermediate before the oxidant was consumed was pernigraniline and it was reduced to emeraldine base rapidly by aniline in the termination period. A mechanism of chain propagation was proposed. Chain propagation and autoacceleration period were almost independent of addition of pernigraniline, and the autoacceleration of aniline polymerization is due to more rapid initiation rate.

Solutions of polyaniline (PAn), poly (ortho-toluidine) (POT) and poly (ortho-anisidine) (PAs) in N-methyl pyrrolidinonne (NMP) were examined by viscometric, gel permeation chromatographic (GPC) and rheological methods. Strong intermolecualr interaction and molecular aggregation are shown.

To enhance the photoluminescence and electroluminescence efficiency, light-emitting polymers with energy transferring chromophorcs including N,N,N'N'-phenylene-diamine, naphthalene-imide, oxadiazole, meta-phenylene vinylene are designed and synthesized.

The catalyst structure of Ti(OBu)4-AlEt3 at different Al/Ti ratios before and after heat aging has been investigated from the data of UV, GC-MS, ESR and C-13 NMR spectra. The complex compounds formed by HTiEt2 and AlEt2(OBu) exist mainly in the catalyst solution, and no -OBu ligands linking with Ti atoms can be found at an Al/Ti ratio of four before heat aging. Many kinds of catalytic species with different size are formed after heat aging the catalyst at 110-degrees-C for 2 h. Dehydrogenation, accompanied by the valence change from Ti3+ to Ti2+, is observed during the aging process of the catalyst.

A surface emitting microcavity was formed by sandwiching a polymer film containing PVK, Alq(3) and DCM between a distributed Bragg reflector (DBR) with a reflectivity of 99% and a silver film (300 nm). The lasing phenomenon was observed in DCM-doped PVK microcavity. The full width at half maximum (FWHM) was 0.6 nm with the peak wavelength at 603 nm. The threshold energy for lasing was estimated to be about 2.5 mu J per pulse. (C) 2000 Published by Elsevier Science S.A. All rights reserved.

The reactions of polyaniline and poly-omicron-methylaniline of different oxidation degrees with I2 were followed by FTIR and electrical conductivity measurements. The results showed that the reaction of common polyanilines with I2 was oxidation in nature whereas that of the fully reduced ones was doping. The latter took place in two steps: oxidation of benzene-diamine units into quinone-diimine units (redox between I2 and the polymer chain) and formation of a conjugated system consisting of four aromatic rings (intramolecular chain redox).

The chemical polymerization of ortho-methylaniline (MAn) is performed in aqueous solution of six protonic acids. The MAn polymerization conversion, and the electrical conductivity and doping level as well as molecular chain structure of the polymers obtained depend not only on the acid concentration but also on their acidity and molecular size.

A novel doping phenomenon of fully reduced polyaniline and poly-o-methylaniline, “light-assisted oxidative doping”, was found for the forst time. The doping reaction was followed by FTIR, UV-VIS, ESR and electrical conductivity measurements. It was shown that the fully reduced polyanilines in the form of HCl-salts undergo a spontaneous transition from an insulator or semiconductor to a conductor when exposed to air and light, and their final molecular chain structures are analogous to those found in HCl-doped common polyanilines.

With a newly synthesized poly(p-phenylene vinylene) (PPV) multiblock copolymer used in a triple-layer structure, efficient green light-emitting diodes with low driving voltage have been fabricated. The devices are turned on at 2.5 V, the brightness at 5 V is above 100 cd/m(2) and at 7 V is about 1650 cd/m(2), with an external quantum efficiency of about 1%. (C) 1998 Elsevier Science S.A. All rights reserved.

A class of efficient electrophosphorescent materials of cyclometalated iridium complexes was reported. Their UV, PL and EL properties were studied. For these iridium complexes doped polymer light-emitting devices using CN-PPP as host matrix, intense red electrophosphorescence with an external quantum efficiency of 1.3% was achieved. The effect of cyclometalated iridium complex on electrophosphorescence was also discussed.

Photoluminescence and electroluminescence from a new conjugated dendrimer consisting of three distyrylbenzene units linked by a central nitrogen atom as core and meta-linked biphenyl units as dendrons were investigated. Bright electroluminescence was realized by using bilayer devices with blurred interface, which were fabricated by sequentially spin-coating a neat dendrimer and a dendrimer doped with 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD). By optimizing the concentration of PBD, the maximum brightness and EL quantum efficiency reach 4100 cd/m(2) and 0.10%, respectively.

A novel thermally stable terbium carboxylate complex, Tb(MTP),(phen) (MTP=monotetradecyl phthalate, phen=1,10-phehanthroline). was synthesized and characterized. The device structure of glass substrate/indium-tin-oxide/poly(p-phenylenevinylene) (PPV)/poly (N-vinycarbazole) (PVK):Tb(MTP),(phen): 1,3,4-oxadizole derivative (PBD)/tris(8-hydroxyquinoline) (AIq 3 )/aluminum (Al) was employed to study the electroluminescent properties of Tb(MTP),(phen). A green emission with extremely sharp spectral band of less than 10 nm at 544 nm peak wavelength was observed. A maximum luminance of 152 cd/m 2 and an external quantum efficiency of 0.017% were achieved at a drive voltage of 24 V. A possible mechanism of energy transfer based on the polymer doped with lanthanide organic complex was also proposed.

The PL and EL properties of the polymer blends of PVK and blue PPV copolymer were studied. Considerable enhancement of both the photoluminescent and the electroluminescent intensity were observed by using the polymer blends as emission layer in the LED devices. The energy transfer process and the formation of exciplex in the polymer blends were also discussed.

A series of novel PPV derivative copolymers with good solubility in common organic solvents were synthesized. The emitting color of these copolymers could range from red to blue by adjusting the structures and the compositions of monomers. Investigation on their optical properties showed that the PL quantum efficiency could be increased by energy transfer and conjugation reduction. The PL quantum efficiency of most green/blue copolymer films on slide glass was higher than 80%.

Bright blue electroluminescent devices have been fabricated using poly( N -vinylcarbazole) (PVK) doped with perylene as the emissive layer, poly( p -phenylenevinylene) (PPV) as the hole-transporting layer, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), tris(8-hydroxyquinoline) aluminum (Alq 3 ) as the electron-transporting layer, and Al as the cathode. A luminance of 700 cd/m 2 and a luminescent efficiency of 0.8% are achieved at a drive voltage of 36 V. In the experiment, it is found that the introduction of electron-transporting layer PBD has a great effect on the emissive color of the electroluminescent devices prepared by PVK doped with perylene. Yellow-green emission is observed from the device structure of glass substrate/indium-tin-oxide/PVK:perylene/Al. The possible emissive mechanisms are given. The effect of the transporting layer on the electroluminescence is also discussed.

A soluble polymer emitting green color with high efficiency was synthesized. Bright green electroluminescence devices, both single layer and multilayer, were fabricated. The luminous efficiency was improved dramatically. Carrier injection from the electrodes to the emissive layer and concomitant green electroluminescence from the emissive layer were observed. A luminance of 920 cd/m(2) and luminous efficiency of 5.35 1m/W were achieved at a drive voltage of 15 V for the multilayer device. (C) 1997 Elsevier Science S.A.

Polyaniline was doped with sulfonated PS, PPO and PEEK. The properties of doped polyaniline depended on the processing method and the structure of main chain backbone of the macromolecular acid.

Oxidative polymerization of aniline in the presence of H2O2/Fe2+/HCl was carried out, and polyaniline obtained showed similar molecular structure compared to that prepared in (NH4)2S2O8 system.

Soluble poly (o-toluidine) (POT), poly(o-anisidine) (PAs) and poly (o-chloroaniline) (PCAn) were doped with camphorsulfonic acid (CSA). The conductivity and UV-Vis spectra of the CSA-doped POT, PAs and PCAn were studied. These properties were found to be dependent on the solvent used. The cast films from m-cresol solution exhibit more effective doping and higher conductivity.

The interaction of N-methyl-2-pyrrolidone (NMP) and organic acid doped polyaniline (PAn) is studied by UV-Vis-NIR spectroscopy. A dedoping effect is observed when the doped PAn solution is extremely diluted by NMP. This effect is due to a strong interaction between NMP and the dopant acid. The competition between NMP and PAn is responsible for the poor conformation of doped polyaniline in NMP solution and the poor conductivity of the film cast from this solution.

The present paper reports the synthesis of glycidyl monoether of 4-[(p-nitrophenyl) azo] phenol (GMNA) and crosslinking reaction of GMNA with hexamethylene diisocyanate biuret (HDIB). The Tg of crosslinked polymer was investigated by DSC. The orientation and stability of the poled and crosslinked polymer film were studied by UV-Vis spectra and Maker fringe method.

Thermal behavior of polyaniline (PAn) doped with kinds of inorganic or organic acids under desired atmosphere were studied by TG, DSC and in-situ electrical conductivity measurements. The reason for the thermal stability of electrical conductivity of doped PAn was discussed.

Aluminum solid electrolytic capacitors with polyaniline doped with inorganic and organic acids as counterelectrode were fabricated, their properties were studied.

Summary form only given. Macromolecular complex of polyaniline/sulfonated polystyrene (PAn/SPS) has been prepared. The complex in which the sulfonation degree of SPS is lower than 15mol% in doped state is soluble in N-methyl pyrrolidinone (NMP) or THF and its NMP or THF solution can be diluted by chloroform or pyridine. But once the sulfonation degree of SPS is over 15mol% the complex is insoluble in any solvents because of strong ionic cross-linking. The complex film in doped state can be directly prepared with solution casting. The electrical conductivity of the film ranges from 10/sup -8/ to 10/sup -4/S/cm. For PAn content below I0wt% the electrical conductivity increases with PAn content. Above I0wt%, it remains almost constant. The complex exhibits three absorption bands in UV-Vis spectra at 325, 430 and 750-800nm, respectively. The band at 750-800nm shifts toward longer wavelength with the increase of PAn content. When NMP solution of the complex is diluted with NMP, PAn is dedoped, but when it is diluted with THF, pyridine or cyclohexanone, PAn is still in doped state. PAn and SPS have good compatibility. Thermal stability of the complex is enhanced with increase of PAn content or conversion of SO/sub 3/H into SO/sub 3//sup -/.

Voltammetry was used to study the effect of anions of supporting electrolyte, aniline oxidation potential and pH of solution on electrochemical polymerization of aniline. It was found that the polymerization rate of aniline on polyaniline-covered Pt electrode is dependent upon the morphological structure of polyaniline films formed in different acids. The higher polymerization rate was observed for polyaniline with granular or net morphological structure. The irreversible oxidation of polyaniline occurs simultaneously with aniline polymerization. The rate of PAn oxidation increases with increasing potential and destruction of polyaniline is observed. The voltammograms of aniline oxidation in pH range of −0.75 – 2.4 were measured and the mechanism of aniline polymerization in acid solution is discussed.

The infrared spectra of soluble polyaniline (PAn) have been studied. It is found that the i.r. spectrum of the soluble PAn gives more structural information than those of insoluble samples. A tentative assignment is given based on the observed effects of HCl concentration in the polymerization system on the i.r. spectra of the PAn obtained and on the spectral changes during HCl or I2 doping and NH3 undoping.

Soluble polytoluidine was reacted with phenylhydrazine and iodine to obtain polytoluidines with different degrees of oxidation. Their reactions with HCl were followed by i.r. spectroscopy. Based on their spectral changes, a doping mechanism was proposed.

Polymerisation anodique de l'aniline sur une electrode de Pt dans les electrolytes de base H 2 SO 4 , HCl et HClO 4