Characterization of ZnO:AI films deposited by r.f.magnetron-sputtering at low temperature

Transparent conducting ZnO:AI thin films with good adhesion and Iow resistivity have been prepared on organic substrates and Coming 7059 glass substrates by r.f. magnetron-sputtering technique at Iow substrate temperature (25-210℃). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed.High quality films with resistivity as Iow as 1.0 x 10- 3Ω@ cm and 8.4 x 10- 4Ω@ cm, the average transmittance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates.     

The Gas Sensitivity of Polypyrrole Film Fabricated by in Situ Polymerization

1 Results Polypyrrole (PPy) is a typical conducting polymer with high conductivity and good stability,and has been widely used for detection of gases including ammonia and nitroxide[1].However the reversiblity and selectivity of the response to these gases are always not satisfying.In the paper,conductive PPy film was deposited on the interdigital electrode modified by one bilayer of poly(diallyldimethylammonium chloride) and poly(sodium styrenesulfonate),by in-situ polymerization with FeCl3 as oxidizin...     

Structural properties of charged diblock copolymer solutions

Aqueous micellar solutions of ionic/neutral block copolymers have been studied by light scattering, small angle neutron scattering and small angle X-ray scattering. We made use of a polymer comprised of a short hydrophobic block (polyethylene-propylene) PEP and of a long polyelectrolytic block (polystyrene-sulfonate) PSSNa which has been shown previously to micellize in water. The apparent polydispersity of these micelles is studied in detail, showing the existence of a few large aggregates coexisting with the population of micelles. Solutions of micelles are found to order above some threshold in polymer concentration. The order is liquid-like, as demonstrated by the evolution with concentration of the peak observed in the structure factor (), and the degree of order is found to be identical over a large range of concentrations (up to 20 wt%). Consistent values of the aggregation number of the micelles are found by independent methods. The effect of salt addition on the order is found to be weak. Received: 19 June 1997 / Received in final form: 4 September 1997 / Accepted: 9 October 1997     

聚（2,5—二甲氧基对苯乙炔）的可溶性前聚物合成及表征

研究了合成聚（２，４－二甲氧基对苯乙炔）的有机可溶性前聚物的反应条件与单体转化率和前聚物产率的关系。实验结果表明：ＮａＯＨ是聚合反应的有效引发剂，适宜的反应条件为：单体与ＮａＯＨ摩尔比为１：１，单体浓度０．０５－０．２ｍｏｌ／Ｌ，聚合时间２ｈ，温度低５℃，正己烷、石油醚作为有机提取剂可有效提高前聚物产率。用ＩＲ、ＵＶ－Ｖｉｓ＇＾ＨＮＭＲ，ＴＧＡ和 ＤＳＣ对前聚物进行了表征。     

纳米级碳导电剂的种类对licoo2电化学性能的影响

碳纳米管;锂离子电池;正极;倍率容量;导电剂     

Synthesis and thermal stability of the resins prepared from the reactions of 1,4-bis(2,2-dicyanovinyl)benzene with aromatic diamines and electrical conductivity of the resulting materials following pyrolysis

New thermosetting resins were prepared from the reaction of 1,4-bis(2,2-dicyanovinyl)benzene with aromatic diamines in varying molar ratios. The thermal stability of these resins was correlated with their composition and the curing conditions. They were stable in N₂ up to 370–448°C and afforded anaerobic char yields of 73–84% at 800°C after curing at 300°C for 20–60 h. The temperature dependence of the electrical resistivity of all resins pyrolyzed at 700°C for 15 h was studied in the temperature range from ?173–327°C (100–600 K). The results showed that at room temperature the unpyrolyzed polymers have insulating properties, whereas a dramatic decrease in the electrical resistivity is observed following pyrolysis. The temperature dependence of the electrical resistivity suggests that all of the materials studied have semiconducting properties. The observed electrical conductivity is thermally activated with activation energies ranging from 0.03–0.06 eV. © 1994 John Wiley & Sons, Inc.     

高强度聚乙烯醇/聚苯胺/聚吡咯/TiO2导电杂化水凝胶的制备与性能

本文以聚乙烯醇(PVA)、苯胺(ANI)、吡咯(Py)及钛酸丁酯(TBOT)为原料,通过溶胶-凝胶法、原位氧化聚合法及冷冻-融溶法一步得到聚乙烯醇/聚苯胺/聚吡咯/TiO 2(PVA/PANI/PPy/TiO 2)杂化水凝胶。结果表明,该杂化水凝胶具有优异的力学性能和导电性能。当n(ANI)∶[KG-*3/5]n(Py)=8∶[KG-*3/5]2(TBOT体积为100μL)时,其压缩强度高达2.45 MPa。同时,在外加电源的作用下,该凝胶能够使灯泡发光。当n(ANI)∶[KG-*3/5]n(Py)=2∶[KG-*3/5]8(TBOT体积为150μL)时,杂化水凝胶的电导率(0.25 S/m)最好。该杂化水凝胶有望广泛地应用在柔性可穿戴电子器件、安全离子电池、传感器和生物器件等领域。     

PET导电纤维的制取及研究

以过氧化二苯甲酰为引发剂,使丙烯睛在涤沦(PET)纤维上接枝共聚。接枝纤维在含铜化合物,含硫还原剂溶液中反应,制备PET导电纤维。讨论了影响接枝共聚的各种因素,选择出最佳聚合条件。对该纤维的导电成份和结构以及性能进行了研究。     

Effect of hydrocolloids on starch thermal transitions,as measured by DSC

Differential scanning calorimetry (DSC) was used to analyze the influence of different hydrocolloids (xanthan, guar, and locust bean gums, carboxymethylcellulose and sodium alginate) on the gelatinization of corn starch in systems with starch concentration ranging between 0.1 and 0.7 g starch/g mixture. The reduction of available water produced a shift in gelatinization temperature, especially of the conclusion temperature. The effect was more marked for ionic hydrocolloids. The influence of hydrocolloids on glass transition temperature (T _g) of gelatinized starch suspensions and on the glass transition temperature of the maximally freeze-concentrated solute/unfrozen water matrix (T _g) was also studied.T _g onset values ranged between –4.5 and –5.5C for corn starch pastes with and without hydrocolloids. Those hydrocolloids that increased the viscosity of the unfrozen matrix inhibited additional ice formation during thawing (devitrification).Starch concentration and final heating temperature were found to be relevant factors affecting the kinetics of amylopectin retrogradation during frozen storage at –4C. Xanthan gum failed to prevent amylopectin retrogradation; this observation could be attributed to the fact that gums act outside the starch granule, while amylopectin retrogradation takes place within the granule.     

Preparation of conductive polypyrrole (PPy) composites under supercritical carbon dioxide conditions

Electrically conductive composites were prepared via the chemical oxidative polymerization of the pyrrole monomer in polystyrene (PS) and zinc neutralized sulfonated polystyrene (Zn-SPS) films under supercritical carbon dioxide (SC-CO₂) conditions. The strong swelling effect of SC-CO₂ made polypyrrole (PPy) particles not only form on the surface, but also become incorporated into the film, resulting in a homogeneous structure with a relatively higher conductivity. By comparison, the composite prepared in aqueous solutions shows a skin-core structure and a conductivity of 3 to 4 orders of magnitude lower than that of the former due to the diffusion-controlled process of the pyrrole monomer. The percolation thresholds of PS/PPy and Zn-SPS/PPy composites were 6.2% and 2.7% of the volume fraction of PPy, respectively, much lower than the theoretically predicted value of 16%. Moreover, the conductive composites prepared under SC-CO₂ conditions showed higher thermal stability, especially in the high-temperature region. Translated from Chemical Journal of Chinese Universities, 2006, 27(4): 771–774 (in Chinese)