Electrochemical copolymerization of aniline and aniline-2,5-disulfonic acid (ADSA) was carried out in HCI solutions. The presence of ADSA inhibited significantly the growth of polyaniline (PAn), although the voltammetry of the copolymer was still similar to that of conventional PAn. As the ADSA concentration increased, the deposition rate of the copolymer decreased rapidly and finally no solid film was deposited on the electrode surface. When the ADSA concentration was lower than-5 mM, the depression effect of ADSA on the growth rate of the copolymer is mainly due to its stronger adsorption at the electrode surface. For higher ADSA concentrations, the inhibiting effect of ADSA was dominated by its termination effects, which led to more soluble oligomers and in turn resulted in lower deposition efficiency. Electrolysis of ADSA solution might result in a water-soluble fully sulfonated PAn. aniline, aniline-2,S-disulfonic acid, copolymerization, polyaniline, water-soluble

In aqueous acidic solutions, a higher peak current and a more positive peak potential for the first oxidation peak of polyaniline (PAN) compared with those obtained in a multicycle voltammogram was observed after holding at a sufficiently negative potential. This is referred to as a memory effect in PAN. An exception to this behavior was observed at low scan rate, when the peak potential in the first voltammogram can be less positive than that in the multicycle voltammogram. When the solvent was substituted by a mixture of water and some organic solvents, the first oxidation peak obtained in aqueous solution split into two subpeaks. The first subpeak, with a less positive peak potential, contributed strongly to the memory effect observed in PAN, but the second subpeak, with a more positive peak potential, was little influenced by holding in the reduced state. The exception mentioned above could be explained in terms of the existence of these two subpeaks if it could be shown that they were present for PAN in any solvent. These two subpeaks may reflect different structures in reduced PAN or be due to solvent effects on PAN intermediates during cycling.

Effects of metallophthalocyanines (MPcs) are systematically investigated on electroluminescence (EL) characteristics of ITOy MPcyTPDyAlq3yMg-Ag devices. A linear relationship is found between driving voltages of the devices and energies of the highest occupied molecular orbital (HOMO) level of MPcs, showing that the driving voltage of the device is substantially determined by the energy barrier for hole injection at the ITOyMPc interface. When an MPc having a higher HOMO level, such as CuPc or ZnPc, is selected as a hole transport material, the driving voltage of the device at a luminance of 100 cd my2 significantly reaches as low as 5.5 V compared with 7.8 V for the device without an MPc layer. The insertion of MPc layer leads to increasing of the EL output, but does not affect the EL efficiency of the devices.

Electropolymerization of aniline in perchloric acid solutions was investigated with presence of para-phenylenediamine (PPDA). Experimental results showed that the presence of PPDA promoted markedly the growth of the polymer. The catalytic effect of PPDA on the polymerization of aniline included its contributions to both the autocatalysis and the external catalysis. Addition of PPDA with an appropriate concentration resulted a polymer with high polymerization degree and higher conductivity, which were closely related to the contribution of PPDA to the autocatalysis in the polymerization of aniline. Memory effects in and else properties of the catalytically electrosynthesized polyaniline were also studied,

Influences of an inserted hole-blocking bathocuproine (BC) layer were investigated on electroluminescence (EL) performances of organic light emitting devices with a configuration of ITO/BC/Alq3/Mg–Ag, where Alq3 is tris(8-quinolinolato)aluminum(III). Variations in the thickness of organic layers and bias voltages were found to alternate the emissive region from the BC layer to the Alq3 layer, resulting in shift of the emission wavelength in the EL spectra of the devices.