Comparative studies of solid‐state synthesized poly(o‐methoxyaniline) and poly (o‐toluidine)

Poly(o‐methoxyaniline) (POMA) and poly(o‐toluidine) (POT) salts doped with different acids (methanesulphonic acid (MeSA), trifluoroacetic acid (TFA), and hydrochloric acid (HCl)) were synthesized by using solid‐state polymerization method. The polymers were characterized by Fourier transform infrared (FTIR) spectra, ultraviolet–visible (UV–Vis) spectrometry, X‐ray diffraction (XRD), cyclic voltammetry (CV), and conductivity measurements. Transmission electron microscopy (TEM) was done to study the morphologies of POMA and POT salts. The FTIR and UV‐Vis absorption spectra revealed that the reduced phase was predominant in POMA salts, and the pernigraniline phase was predominant in POT salts. It was found that POMA salts displayed higher doping level and conductivity. In contrast, POT salts were lower at doping levels and conductivity. In accordance with these results, the electrochemical activity was also found to be lower in POT salts. The XRD patterns showed that the POMA salts displayed higher crystallinity than POT salts. The results from TEM revealed that the morphologies of POMA salts were different from those of POT salts. Copyright © 2008 John Wiley & Sons, Ltd.     

Construction of an exact solution of time-dependent Ginzburg–Landau equations and determination of the superconducting–normal interface propagation speed in superconductors

A new approach is taken to calculate the speed of front propagation at which the interface moves from a superconducting to a normal region in a superconducting sample. Using time-dependent Ginzburg–Landau (TDGL) equations we have calculated the speed by constructing a new exact solution. This approach is based on a method given by Di Bartolo and Dorsey. Our result for the speed agrees with the result of Di Bartolo and Dorsey.     

Higher-order symmetries and conservation laws of multi-dimensional Gordon-type equations

In this paper a class of multi-dimensional Gordon-type equations are analysed using a multiplier and homotopy approach to construct conservation laws. The main focus is the analysis of the classical versions of the Gordon-type equations and obtaining higher-order variational symmetries and corresponding conserved quantities. The results are extended to the multi-dimensional Gordon-type equations with the two-dimensional Klein–Gordon equation in particular yielding interesting results.     

固相反应法制备磷钼酸(H3PMo12O40)掺杂聚苯胺对其电化学活性的影响

利用固相反应法制备了磷钼酸(H3PMo12O40,简称PMA)掺杂聚苯胺,并以红外光谱(FT-IR)、X-射线衍射(XRD)、循环伏安(cyclic voltamm ogram)等测试方法对聚苯胺进行了表征。结果表明,无论是液相法还是固相法,磷钼酸掺杂于聚苯胺中,仍保持自身结构特征,与传统液相合成的磷钼酸掺杂聚苯胺相比,固相反应法合成的磷钼酸掺杂聚苯胺的晶化率和电活性略差。固相反应法制备的磷钼酸掺杂聚苯胺在对抗坏血酸(AH2)电催化氧化中,表现出比液相合成更好的电催化活性。     

The effect of solvents and organic acids on the p-doping behaviors of poly(3′,4′-Ethylenedioxy-2,2′:5′,2″-terthiophene)

Poly(3??,4??-Ethylenedioxy-2,2??:5??,2??-terthiophene) was synthesized by chemical oxidative polymerization of 3??,4??-Ethylenedioxy-2,2??:5??,2??-terthiophene using FeCl₃ as an oxidant. The resulting polymer was characterized by FTIR and ¹H NMR. p-doping behaviors of substituted polyterthiophene with different organic sulfonic acids (methanesulfonic acid, p-toluene sulfonic acid, and ??-naphthalene sulfonic acid) in different solvents (CH₃CN, CHCl₃, THF and DMF) were studied by UV-VIS spectroscopy. The results from structural characterizations showed that the ??,????-bonding predominates in polyterthiophene. The spectroscopic changes in UV-VIS showed that ??-naphthalene sulfonic acid was an efficient doping acid for polymer while varying the solvents. Meanwhile, CH₃CN showed a high efficiency for p-doping of polyterthiophene while varying the doping acids.     

The symmetries and conservation laws of some Gordon-type equations in Milne space-time

In this letter, the Lie point symmetries of a class of Gordon-type wave equations that arise in the Milne space-time are presented and analysed. Using the Lie point symmetries, it is showed how to reduce Gordon-type wave equations using the method of invariants, and to obtain exact solutions corresponding to some boundary values. The Noether point symmetries and conservation laws are obtained for the Klein–Gordon equation in one case. Finally, the existence of higherorder variational symmetries of a projection of the Klein–Gordon equation is investigated using the multiplier approach.     

Synthesis of poly (3,4-ethylenedioxythiophene)/sulfonated cellulose composites in different systems for the electrochemical sensing of paracetamol

Cellulose - In this paper, composites of poly (3,4-ethylenedioxythiophene) (PEDOT) and sulfonated cellulose (SC) were prepared by oxidative polymerization both in CHCl3 and H2O using different SC...     

Solid-state synthesis of poly(3',4'-dimethoxy-2,2':5',2"- terthiophene): comparison with poly(terthiophene) and poly(3',4'-ethylenedioxy-2,2':5',2"- terthiophene)

A new terthiophene monomer: 3',4'-dimethoxy-2,2':5',2"-terthiophene (TMT) was synthesized and characterized by 1H-NMR, 13C-NMR and FTIR. The solid-state oxidative polymerizations of TMT were performed in various ratios of oxidant (FeCl?) to monomer (TMT). The resulting polymers were characterized by 1H-NMR, FTIR, UV-vis-NIR, GPC, X-ray diffraction, CV, as well as TGA and conductivity measurements. The structure and properties of poly (TMT) were compared with those of polyterthiophene [poly(TT)] and poly (3',4'-ethylenedioxy-2,2':5',2"-terthiophene) [poly(TET)] prepared under the same polymerization conditions. After comparative analysis with poly(TT) and poly(TET), the effects of the dimethoxy substituent and FeCl? on the structural and physicochemical properties of the poly(TMT)s were discussed in depth. The comparison suggested that the dimethoxy-substituted polymer did not display higher crystallinity, thermal stability, conductivity and electrochemical activity than ethylenedioxy substituted one. The results also showed that the effect of FeCl? on poly(TMT) was similar that seen with the poly(TT), in which the oxidation degree, electrochemical activity and conductivity increased steadily with increasing [FeCl?/[TT] ratio. Furthermore, the poly(TMT) and poly(TT) are mostly made up of dimers with a small amount of higher molecular weight components.     

Anharmonic solution of Schrödinger time-independent equation

We present here a mathematical explanation of how the Schr?dinger equation for a class of harmonic oscillators possesses exact solutions. Some of the extended potentials used here are not present in the literature.     

联苯胺与二苯胺共聚物的界面聚合及其表征

采用界面聚合法合成了聚联苯胺、聚二苯胺以及联苯二胺与二苯胺的共聚物。利用红外光谱(FT-IR)、紫外可见吸收光谱(UV-vis)、电子扫描显微镜(SEM)、X射线衍射(XRD)、循环伏安等手段初步探讨了单体配比对共聚物形貌、结构及性能的影响。结果表明:界面聚合法合成的聚联苯胺呈现微米级棒状分布,随着共聚物中二苯胺结构单元的增加,棒状结构消失,聚合物趋于颗粒状分布;共聚后聚合物的共轭程度下降,但其结晶性与电化学行为得到了一定的改善;当共聚物中联苯胺与二苯胺的单体摩尔比为1/2时,共聚物电化学行为最佳。