一种新型物理交联型凝胶聚合物电解质的制备与表征

以甲氧基聚乙二醇甲基丙烯酸酯(MPEGM)和十六烷基聚乙二醇甲基丙烯酸酯(HPEGM)为单体, 三乙二醇二甲醚(TEGDME)为增塑剂, 与锂盐(高氯酸锂, LiClO₄)和光引发剂(安息香二甲醚, DMPA)复合制成光敏体系, 经紫外(UV)固化得到物理交联型凝胶聚合物电解质(GPE)薄膜. 用红外(IR)光谱、差热分析(DSC)、拉伸测试和交流阻抗(AC) 等方法对聚合物基体和电解质的性能进行了研究.结果表明: 当共聚物P(MPEGM-co-HPEGM)中HPEGM含量为50%(w)时, 十六烷基链段(C₁₆)在聚氧化乙烯(PEO)链段静电斥力的作用下发生聚集, 自组装形成了物理交联, 提高了共聚物的空间稳定性; 温度和电解质中各组分的含量对电导率均有较大的影响, 综合性能较好的电解质在30℃时电导率可达0.87×10^-3 S·cm^-1; 采用循环伏安法测得该电解质的电化学窗口为0~4.5 V (vs. Li/Li⁺), 可以满足锂离子电池的应用要求; 组装成的LiFePO₄/GPE/Li电池, 在30℃下以0.1 C和0.2 C倍率进行充放电测试, 首次放电容量分别为154.7和148.0 mAh·g^-1.     

锂离子电池PMMA-VAc聚合物电解质的制备与性质研究

以甲基丙烯酸甲酯(MMA)和醋酸乙烯酯(VAc)为单体, 用乳液聚合法合成聚甲基丙烯酸甲酯-醋酸乙烯酯聚合物(PMMA-VAc), 并以此聚合物制备了新型聚烯烃膜支撑的聚合物膜及聚合物电解质. 用红外光谱(FTIR)、凝胶色谱(GPC)、差热和热重分析(DSC/TG)、扫描电镜(SEM)及电池充放电实验等方法研究了聚合物、聚合物膜和聚合物电解质的性质. 红外光谱结果表明, MMA与VAc通过各自的C＝C双键打开聚合成PMMA-VAc. PMMA-VAc易于分散在混合碳酸酯溶剂中并形成凝胶, 凝胶粘度随PMMA-VAc浓度的增加而增加, 当浓度为4%时成膜效果最佳. PMMA-VAc膜具有大量的微孔结构, 具有极强的吸液性能. PMMA-VAc膜具有良好的热稳定性: 在380 ℃范围内保持稳定. 聚烯烃膜支撑的PMMA-VAc膜室温下的离子电导率为1.85×10^－3 S•cm^－1, 用作为锂离子电池的聚合物电解质时, 电池具有良好的循环稳定性和倍率性能.     

侧链型磺化聚芳醚酮/磺化聚乙烯醇复合型直接甲醇燃料电池用质子交换膜

通过溶液共混法制备了不同磺化聚乙烯醇(SPVA)含量的侧链型磺化聚芳醚酮/磺化聚乙烯醇(S-SPAEK/SPVA)复合膜. 应用红外光谱(FTIR)对复合膜进行了表征, 扫描电镜(SEM)显示SPVA均匀分布在复合膜中. 通过对复合膜的性能测试发现该系列复合膜具有良好的热性能、较高的吸水率和保水能力. SPVA中的羟基能有效地阻碍甲醇的透过, 甲醇渗透系数从S-SPAEK/SPVA5 复合膜的7.9×10^-7 cm²·s^-1降低到S-SPAEK/SPVA30的1.3×10^-7 cm²·s^-1, 比S-SPAEK膜的11.5×10^-7 cm²·s^-1降低了一个数量级. SPVA的引入增加了亲水基团数量, 增加了复合膜的吸水和保水能力, 有利于质子按照“Vehicle”机理和“Grotthuss”机理进行传递, 柔软的SPVA链段与S-SPAEK侧链聚集成亲水相区, 形成连续的质子传输通道, 提高了复合膜的质子传导率. 在25 和80℃ 时, S-SPAEK/SPVA30 复合膜的质子传导率分别达到了0.071 和0.095 S·cm^-1. 可见,S-SPAEK/SPVA复合膜有望在直接甲醇燃料电池中得到应用.     

阴离子为羧酸根和芳环共轭的离子液体在染料敏化太阳能电池中的应用

提出了利用p-π共轭效应设计离子液体的方法, p-π共轭效应可以有效分散阴离子的负电荷, 降低离子液体中阴阳离子之间的库仑引力, 以得到低粘度的离子液体. 所设计的离子液体为1-乙基-3-甲基咪唑苯甲酸(EMIB)和1-乙基-3-甲基咪唑异烟酸(EMIIN) (它们的阴离子中羧酸根和芳环为p-π共轭结构), 这两种离子液体都达到了较低的粘度(EMIB为42 mPa·s, EMIIN为27 mPa·s). 进一步将这两种离子液体做成电解质, 应用在染料敏化太阳能电池中, 通过优化电解质的组成, EMIB基电解质达到了1.43 mS·cm^-1的电导率和1.45×10^-7cm²·s^-1的I₃^?的扩散系数, 而EMIIN基电解质的电导率和I₃^?扩散系数分别为1.63 mS·cm^-1和2.01×10^-7 cm²·s^-1,后者电导性能的提高主要和EMIIN粘度较低有关系. 进一步将这两种电解质组装成电池, 在300 W·m^-2的光强下测得EMIB基电池和EMIIN基电池的效率分别为2.85%和4.30%.     

磁控溅射中靶-基底距离与Si共掺对ZnO:Al薄膜性质的影响

使用射频磁控溅射, 在正方形石英衬底上沉积透明导电掺Al的ZnO(AZO)和Si共掺AZO(AZO:Si)薄膜. 系统研究了靶-基底距离(D_st)和Si共掺对AZO薄膜电学、光学性质的影响. 电阻率、载流子浓度和迁移率都强烈地依赖于靶-基底距离, 随着靶-基底距离的减少, 载流子浓度和迁移率都有显著的增加, 电导率也随之提高. 在靶-基底距离为4.5 cm处, 得到最低电阻率4.94×10^-4 Ω·cm, 此时的载流子浓度和迁移率分别是3.75×10²⁰ cm^-3和33.7 cm²·V^-1·s^-1. X射线光电子能谱(XPS)、X射线衍射(XRD)和边界散射模型被用于分析载流子浓度、迁移率和靶-基底距离的关系. 透射谱显示, 在可见-近红外范围内所有样品均有大于93%的平均透射率, 同时随着靶基距离的减少, 吸收边蓝移. AZO:Si表现出可与AZO相比拟的高电导和高透射光学特性, 但在热湿环境中却有着更好的电阻稳定性, 这在实际使用中很有意义.     

P(VAc-MMA)为基体的聚合物电解质研究

以醋酸乙烯酯(VAc)和甲基丙烯酸甲酯(MMA)为单体, 采用半连续种子乳液聚合法制备了无规共聚物聚(醋酸乙烯酯-甲基丙烯酸甲酯)[P(VAc-MMA)], 并以此聚合物为基体制备了聚合物电解质. 用红外光谱(FTIR)、核磁共振氢谱(¹H NMR)、扫描电镜(SEM)、差热/热重分析(DSC/TG)、X射线衍射(XRD)、机械性能测试和电化学交流阻抗等方法对聚合物和聚合物电解质的性质进行了研究. 测试结果表明: VAc和MMA聚合生成P(VAc-MMA); 聚合物膜含有大量微孔结构, 利于离子传输; 聚合物电解质膜具有优良的热稳定性和机械强度; 25 ℃下, 最高的离子电导率达到了1.27× 10^－3 S•cm^－1; 离子电导率随着温度的升高而迅速增加, 电导率-温度曲线符合Arrhenius方程.     

一种新型凝胶态聚合物电解质的制备和性能

采用一种新型胶联剂新戊二醇二丙烯酸酯(noepentyl glycol diacrylate, NPGDA)和聚偏氟乙烯-六氟丙烯(poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP), 液态电解液组成电解质混合溶液, 然后加入引发剂并加热引发聚合反应制备了一种具有互穿聚合物网络结构的凝胶态聚合物电解质, 可以用于制备聚合物锂离子二次电池. 考察了不同PVDF-HFP/NPGDA质量比对凝胶态聚合物电解质性能的影响. 结果表明, PVDF-HFP/NPGDA质量比可以影响凝胶态聚合物电解质的结构形貌、电化学特性以及聚合物锂离子二次电池的性能. 研究发现, 当m(PVDF-HFP)/m(NPGDA)＝1:1时制备的凝胶态聚合物电解质具有较高的离子电导率和电化学稳定窗口, 室温下分别为6.99×10^-3 S•cm^-1和4.8 V(vs Li⁺/Li), 以其为电解质制备的聚合物锂离子二次电池具有较好的电化学性能.     

添加剂对离子液体凝胶聚合物电解质电化学性能的影响

本文采用1-乙基-3-甲基咪唑六氟磷酸盐(EMIPF₆)、六氟磷酸锂(LiPF₆)和偏氟乙烯-六氟丙烯共聚物(P(VdF-HFP))为原料制得P(VdF-HFP)-EMIPF₆-LiPF₆体系离子液体凝胶聚合物电解质,选取碳酸甲乙酯(EMC)、碳酸二甲酯(DMC)、碳酸二乙酯(DEC)以及碳酸乙烯酯(EC)和碳酸丙烯酯(PC)混合物(EC-PC)作为离子液体凝胶聚合物电解质的添加剂,分别研究了它们对聚合物电解质膜电化学性能的影响。结果表明：加入EC-PC的P(VdF-HFP)-EMIPF₆-LiPF₆电解质膜的电化学窗口达到4.6 V,锂离子迁移数为0.44,30 ℃时离子电导率为1.65 mS·cm^-1;而DEC、DMC、EMC对电解质膜的电化学稳定性、锂离子迁移数存在不良的影响,对离子电导率的提高不明显。研究了正极材料LiCoO₂在P(VdF-HFP)-EMIPF₆-LiPF₆+EC-PC电解质中的充放电循环性能,其首次放电比容量达到116.5 mAh·g^-1,充放电20次后,电池容量没有明显衰减。     

LaAlO3基电解质与阳极材料的化学相容性及电化学性能

采用甘氨酸-硝酸盐法(GNP)合成La_0.90Sr_0.10Al_0.97Mg_0.03O_3-δ (LSAM)粉体, 成型后经1500 °C、5 h 烧结的样品, 900 °C时其电导率为1.11×10^-2 S·cm^-1. 利用X射线衍射(XRD)、扫描电镜/X 射线能谱分析(SEM/EDX)和交流阻抗技术等表征手段研究NiO-Ce_0.9Gd_0.1O_1.95 (Ni-GDC)、Sr_0.88Y_0.08TiO₃ (SYT)和La_0.75Sr_0.25Cr_0.5Mn_0.5O₃(LSCM)三种阳极材料与LSAM电解质的化学相容性. 结果表明, SYT 和LSCM与LSAM的化学相容性欠佳,SYT中的Sr²⁺和Ti⁴⁺向LSAM晶格的扩散明显, LSCM中的Mn³⁺和Cr³⁺向LSAM晶格的扩散显著; 而Ni-GDC与LSAM具有良好的化学相容性, 在1300 °C下两材料间阳离子的相互扩散作用极小. 800 °C时Ni-GDC的比表面极化电阻(RASP)值为5.12 Ω·cm². LSAM 电解质(厚度为550 μm)支撑的Ni-GDC/GDC/LSAM/GDC/LSF(La_0.75Sr_0.25FeO₃)单电池, 在800 °C时电池的开路电压为0.925 V, 最大功率密度为19.5 mW·cm^-2.     

染料敏化太阳能电池中大孔TiO2薄膜电极的制备及应用

采用溶胶-凝胶水热法制备了TiO₂纳晶薄膜电极，晶型为锐钛矿型。为了提高电极的光电性能，利用聚苯乙烯小球做造孔剂，制备了含有大孔隙的TiO₂纳晶薄膜电极，孔径约为200 nm，该电极具有较好的光漫反射性能，更重要的是球形大孔的存在，提高了凝胶电解质在TiO₂薄膜电极中的渗透和I₃^-离子的扩散性能，与不含大孔的TiO₂电极相比，电池的短路光电流提高约2 mA·cm^-2，光电转换效率提高0.6%。     

Pyrolysis/Gas chromatography/mass spectrometry of polymers: Polyisopropenylcyclohexane and copolymers with its aromatic counterpart, α-methylstyrene

Flash pyrolyses at 400, 650, and 900°C of polyisopropenylcyclohexane (PIC) and copolymers, produced by partial hydrogenation of poly-α-methylstyrene (PAMS), have shown that the decomposition of the PIC or IC sequences is complex. In comparison, PAMS and AMS sequences give only depolymerization to monomer at the two lower temperatures but a more complex degradation at 900°C, based on the products identified. It is interesting to note that traces of decalin solvent initiated the depolymerization of PAMS and the AMS sequences in the copolymers at 400°C. The products identified by copolymer pyrolyses indicated that no reaction occurred between S and IC units during decomposition. Average sequence data on the copolymers could not be determined because of the facile unzipping of the AMS sequences and the greater thermal stability of the IC sequences. The fragmentation pattern did indicate that partial hydrogenation of PAMS had produced random copolymer and not a blend of two homopolymers.     

高选择性快速检测Hg2+的磺酰腙型探针的合成及其在吸附和HeLa细胞中的应用

以苯磺酰肼和4-二苯胺基苯甲醛为原料,通过缩合反应设计和合成了一种新型磺酰腙汞离子(Hg²⁺)探针N’-(4-(二苯氨基)亚苄基)苯磺酰腙(S1).在二甲基亚砜(DMSO)/H₂O(V∶V=7∶3,pH=7)溶液体系中,S1对Hg²⁺展示出快速响应、高选择和高荧光灵敏性.通过¹H NMR和HRMS探究了可能的机理.聚丙烯酰胺(PAM)掺杂S1(PAMS)对Hg²⁺有高的吸附性能,其去除率达到99.99%,并且在紫外灯下通过肉眼很容易区分.通过扫描电子显微镜(SEM)观察了PAMS吸附前后的微观形貌.此外,S1具有优异的生物相容性,可以极好地检测HeLa细胞中的Hg²⁺.     

Ion binding in sulfonate-containing polyelectrolytes

Emf measurements have been used to study the activity and the extent of sodium ion binding to several polyelectrolytes, poly(styrenesulfonate) (PSS), poly(2-acrylamido-2-methylpropanesulfonate) (PAMS), poly(3-methacryloyloxypropane-1-sulfonate) (PMOS), and copoly[(N-t-butylacrylamide)-(2-acrylamido-2-methylpropanesulfonate)] (NB–AMS) (mole ratio 3.8:1). The activity coefficient of sodium ion in Na-PAMS and Na-PMOS without added salt is found to be in the range from 0.1 to 0.3 and is insensitive to changes in polymer concentration. However, it increases with increasing concentration of the added salt. The extent of sodium ion binding at a given sodium ion concentration, as estimated from the activity data for some sodium and tetrabutylammonium (TBA) salts, decreases in the order Na-PAMS ≈? Na-PMOS > TBA–PAMS > TBA–(NB–AMS). This indicates that a significant portion of the binding is attributed to the binding of TBA⁺ ions. Also compared are the results of ion binding in Na-PAMS and Na-PSS as a function of ionic strength. At low ionic strength (<1.0M), the order of binding strength is Na-PAMS > Na-PSS, while the order is reversed at high ionic strength (>1.0M). This finding is in good agreement with data obtained by dilatometry and viscometry.     

核苷与碱基的苯胺甲基键合硅胶固定相高效液相色谱分离

建立苯胺甲基键合硅胶固定相(PAMS)高效液相色谱分离核苷与碱基的方法；研究流动相有机溶剂浓度、磷酸缓冲液pH值、离子强度对核苷和碱基在该键合固定相上的色谱保留及分离选择性的影响，用磷酸缓冲液(pH＝4)为流动相快速分离了部分核苷与碱基。     

Missing in total OH reactivity of VOCs from gasoline evaporation

Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds (VOCs). Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method (CRM) using proton transfer reaction mass spectrometer (PTR-MS). Compositions of 56 PAMS (photochemical assessment monitoring station) nonmethane hydrocarbons (NMHCs) were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57±4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. Wesuggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control.     

PAMS基凝胶型聚合物锂电池的制备及电化学性能表征

An admixture of acrylonitrile, methyl methacrylate, styrene and commercial liquid electrolyte (LB302, 1 mol/L solution of LiPF6 in 1∶1 EC/DEC) was enclosed in CR2032 cells. The assembled cells were then γ-ray irradiated using configurations of LiNi0.8Co0.2O2/Li half cells. Through this in-situ irradiation polymerization process, rechargeable lithium cells with poly(acrylonitrile-co-methyl methacrylate-co-styrene) (PAMS) were obtained based gel polymer electrolytes. The structure and thermal stability of PAMS were characterized by FT IR and DSC analyses. The electrochemical properties and charge discharge performance of PAMS-based gel-polymer lithium cells were evaluated by AC impedance spectroscopy, cyclic voltammetry and gavanostatic battery cycling. The results indicate that the in-situ gama-ray irradiation approach is convenient to prepare gel-polymer lithium cells with good charge-discharge performance.     

Pulsed radiofrequency glow discharge time‐of‐flight mass spectrometry for molecular depth profiling of polymer‐based films

We demonstrate the potential of an innovative technique, pulsed radiofrequency glow discharge time‐of‐flight mass spectrometry, for the molecular depth profiling of polymer materials. The technique benefits from the presence, in the afterglow of the pulsed glow discharge, of fragment ions that can be related to the structures of the polymers under study. Thin films of different polymers (PMMA, PET, PAMS, PS) were successfully profiled with retention of molecular information along the profile. Multilayered structures of the above polymers were also profiled, and it was possible to discriminate among layers having similar elemental composition but different polymer structure. Copyright © 2009 John Wiley & Sons, Ltd.     

A model of direct potentiometric determination of nitrate

Summary The paper represents a model for evaluation of the combined influence of four interferences in the direct potentiometric determination of nitrate in soil samples. The correction of the complex analytical signal is performed by the use of the system-oriented technique PAMS and modern statistical methods for modelling and optimization of multi-factorial systems. It is shown that within certain concentration intervals the effect of the interferences is not simply additive as predicted by the Nikolsky equation.On leave from Faculty of Chemistry, University of Sofia, 1126 Sofia, A. Ivanov Ave. 1, Bulgaria     

Some aspects of nitroxide-mediated living radical polymerization of N-(p-vinylbenzyl)phthalimide

The free radical polymerization of N-(p-vinylbenzyl)phthalimide (VBP) “initiated” with the adduct of 2-benzoyloxy-1-phenylethyl and TEMPO (BS-TEMPO) or TEMPO-terminated polystyrene (PS-TEMPO) in N,N-dimethylformamide (DMF) at 125 °C was found to proceed in a living fashion, providing low-polydispersity PVBP and block copolymers of the type PS-b-PVBA, where TEMPO is 2,2,6,6-tetramethylpiperidinyl-1-oxy. Unlike TEMPO-mediated styrene polymerization, the polymerization rate slightly but distinctly depended on the adduct concentration, which was interpretable as a pre-stationary behavior. The hydrolysis of those polymers gave poly(p-aminomethylstyrene) (PAMS) and PS-b-PAMS, and further treatment of the block copolymer with hydrogen chloride provided an amphiphilic block copolymer. The polymeric amphiphile was used as an emulsifier in emulsion polymerization to produce a positively charged polymeric microsphere.     

Membrane extraction of metal ions by aminophosphoryl reagents in the active transport conditions

The process of membrane extraction of rare earth ions, Nd(III), Sc(III), and Sm(III), and also the accompanying them in the natural raw material ions Al(III) and Mg(II), by N,N-bis(dihexylphosphorylmethyl)octylamine (BPA) was investigated under the conditions of active membrane transport, and its high efficiency and selectivity was demonstrated with respect to the two first rare earth metals. The influence of principal parameters of the three-phase extraction process, including the nitrate ion concentration, the releasing aqueous phase acidity, the extracting agent concentration in the membrane, and the nature of the membrane solvent, on the membrane permeability, characterizing the efficiency and selectivity of membrane transporters, was established. Comparison of the membrane permeability in the process of transmembrane transport of Nd(III) and Sc(III) with BPA and monophosphorylated amines showed a significant advantage of the biphosphorylated amine extractant.