Study on Conductivity Properties of PEDOT Prepared through a Modified LB Film Method

Adopting LB film method, an arachidic acid (AA)/PEDOT multilayer LB film was chosen, and polymerized EDOT monomers in hydrophilic group of LB to prepare arachidic acid (AA)/PEDOT multilayer LB film. UV‐Vis, FT‐IR and XPS analyses implied that EDOT was effectively polymerized in film, and thus PEDOT conducting polymer was produced. Analyses of XRR and SIMS indicated that film had a well‐arranged lamella structure, and further research showed that polymerization of EDOT in AA film destroyed the orderliness of the original LB film. This phenomenon could be related to the destructive effect of polymerization on layered structure. We used four‐point probe and semiconductor instrument to study the conductivity property of the film, and observed that the conductivity of AA/PEDOT film had sudden changes with the processing time of changes in effective conduction network. That was caused by "permeability" in conducting channel of multilayer film. The test results also indicated that the conductivity of AA/PEDOT film was obviously better than that of spin‐coating PEDOT/PSS film or that of ODA‐SA/PEDOT‐PSS film, which was due to the higher π structure of PEDOT structure and ordered film structure.     

Structural and micro structural studies of PbO-doped SnO2 sensor for detection of methanol,propanol and acetone

In the present work the structural information of PbO-doped SnO2 thick film sensor has been investigated with X-ray diffractometer (XRD) and scanning electron microscope (SEM). Initially, SnO2 powder was derived using sol-gel process and was subsequently doped with PbO and ground up to nanosized particles. A suitable gas sensor structure was fabricated on 1′′×1′′ alumina substrate using thick film technology. The necessary paste for screen printing was also developed. SEM results showed sol-gel derived powder gets more agglomerated in the thick film form. The sensitivity of the sensor has been investigated at different temperatures (150 ?C?350 ?C) upon exposure to methanol, propanol and acetone, yielding a maximum at 250 ?C for acetone with 1 wt% PbO-doping while at 350 ?C for propanol with 3 wt% PbO-doping of the sensor. The reduction of particle size to nanometers (validated through XRD) leads to a dramatic improvement in sensitivity of sensors for the chosen organic vapors. The results also correlate well with the microstructural properties of the material and the dopant.     

Investigation on Semi-conductive Properties of Hot Growth Film on 316L Austenitic Stainless Steel

The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy(EIS) and Mott-Schottky analysis.The chemical compositions of the hot growth films were detected by X-ray photoelectron spectroscopy(XPS).The results show that the transfer resistance and film resistance increase with increasing temperature to 400℃,then they decrease sharply with further continuously increasing temperature.Formation time plays an important role in determ...     

Effects of Co-addition of DBS and PEG on Wetting Performance of TiO_2 Film

Nanocrystalline anatase TiO2 films with indium tin oxide(ITO) coated glass as the film substrate were fabricated through spin-coating technique. The TiO2 pastes were prepared with sodium dodecylbenzenesulfonate(DBS) modified TiO2 nanocrystals, synthesized by sol-hydrothermal processes in advance, together with different amounts of polyethylene glycol(PEG) macromolecules. The as-prepared films were mainly characterized by ultraviolet-visible (UV-Vis) spectroscopy, field emission scanning electron microscopy(...     

可膨胀石墨阻燃高回弹聚氨酯泡沫塑料的性能

在原料中添加可膨胀石墨(EG),采用一步法合成了阻燃型高回弹聚氨酯软泡,研究了EG对泡沫性能的影响.用扫描电镜和光学显微镜观察了EG粒子在泡沫内的固着状态及其对泡孔形貌和泡沫燃烧后的炭层形貌的影响.垂直-水平燃烧实验和极限氧指数实验检测了EG的添加量对于泡沫燃烧的抑制情况.考察了EG粒子的含量对泡沫密度、拉伸及压缩力学...     

Synthesis and thermal behavior of a novel UV‐curable transparent flame retardant film and phosphorus‐nitrogen synergism of flame retardancy

A novel phosphorus monomer (PDHA) has been synthesized through phenyl dichlorophosphate (PDPC) reacting with 2‐hydroxyethyl acrylate (HEA). The structure of PDHA was characterized by Fourier transform infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance spectroscopy (¹H NMR). A series of UV curable resins were manufactured by blending PDHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratios. The fire performance was examined by micro‐scale combustion calorimeter (MCC) and limiting oxygen index (LOI). The results obtained from MCC indicated that the addition of PDHA to TGICA reduced the HRR and HRC. In addition, the LOI values varied from 28 to 34. The char residues of the composites were observed by scanning electron microscopy (SEM). Their thermal degradation behavior was investigated by thermogravimetric analysis and real time FTIR analysis (RT‐FTIR). The test results indicated that when the weight ratio of PDHA/TGICA = 1:1, the onset temperature of the composite was highest and the most char residue at 700°C was observed. RT‐FTIR showed that the phosphate group of PDHA first degraded to form poly(phosphoric acid)s at around 300°C, which had the major contribution to form the compact char to protect the sample from further degradation. Copyright © 2010 John Wiley & Sons, Ltd.     

Mechanical behavior and wrinkling patterns of phase-separated binary polymer blend film

The wrinkling of phase-separated binary polymer blend film was studied through combining the Monte Carlo (MC) simulation for morphologies with the lattice spring model (LSM) for mechanical properties. The information of morphology and structure obtained by use of MC simulation is input to the LSM composed of a three-dimensional network of springs, which allows us to determine the wrinkling and the mechanical properties of polymer blend film, such as strain, stress, and Young’s modulus. The simulated results show that the wrinkling of phase-separated binary polymer blend film is related not only to the structure of morphology, but also to the disparity in elastic moduli between polymers of blend. Our simulation results provide fundamental insight into the relationship between morphology, wrinkling, and mechanical properties for phase-separated polymer blend films and can yield guidelines for formulating blends with the desired mechanical behavior. The wrinkling results also reveal that the stretching of the phase-separated film can form the micro-template, which has a wide application prospect.     

Development of a Biomimetic Enzyme‐linked Immunosorbent Assay Method for the Determination of Methimazole in Urine Sample

A fast and direct competitive biomimetic enzyme‐linked immunosorbent assay (BELISA) method was developed for the determination of methimazole (MMZ) in urine sample based on a molecularly imprinted film as an artificial antibody. This is the first example to monitor methimazole with a direct competitive biomimetic enzyme‐linked immunosorbent assay (BELISA) method. The imprinted film was directly synthesized on the well surface of MaxiSorp polystyrene 96‐well plate and characterized. The results showed that it exhibited an antibody‐like binding ability, rapid adsorption speed, high stability, which was particularly advantageous and suitable for BELISA development. The BELISA method established in this paper had a higher selectivity for MMZ than for the structurally related compounds and the IC₅₀ (calculated as the concentration giving 50% inhibition of color development) and the detection limit values under optimized experimental conditions were 70 ± 4 μg L^‐1 and 0.9 ± 0.04 μg L^‐1, respectively. The method was applied to the determination of MMZ in spiked urine sample with excellent recoveries ranging from 90% to 95%, and the imprinted film was able to be reused for 20 times without loss of sensitivity. The results obtained by BELISA correlated well with that obtained by the high performance liquid chromatography (HPLC) method.     

Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex

Spectral–optical–electrical–thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO₂)₂-8HQ)₂], were explored, studied and evaluated in this work. Thin films of Ca[((NO₂)₂-8HQ)₂] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200–2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO₂)₂-8HQ)₂] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current–voltage characteristics of Ca[((NO₂)₂-8HQ)₂] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current–voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20–40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO₂)₂-8HQ] and Ca[((NO₂)₂-8HQ)₂] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO₂)₂-8HQ)₂] complex.