射频溅射制备的多晶ZnO膜表面氧的吸附和脱附

多晶的六角密排的ｃ轴平行于衬底的ＺｎＯ膜已用射频溅射的方法制备出来，一电场感应的氧吸附在这些膜上被观察到由紫外光照射或与Ａｒ离子反应所产生的氧的脱附可使膜的电导率增加６－７个数量级，并且一个积累层在膜的表面显现出来。     

温度对碳膜内氮、氧渗透分离影响的非平衡模拟

采用双控体积巨正则系综分子动力学(DCV-GCMD)方法, 用二维狭缝代替传统的一维狭缝构建膜孔模型研究了温度对氮氧纯气体及其混合物在碳膜内的渗透特性, 探讨了氮氧分离机理. 提出了一种新的计算二元混合气体中各组分通量和分离系数的方法, 即模拟中引入迭代, 解决了前人忽略低压侧气体组成和压力影响的问题. 试验结果表明: 当氮氧以纯气体的形式分别透过碳膜时, 二者均遵循Knudsen扩散方式, 且低温下氮气具有较大的渗透性质; 而当二者以混合物的形式一起透过碳膜时, 低温下二者之间存在竞争吸附, 孔宽对气体的渗透影响显著, 尤其是膜孔较小的时候, 分子筛效应控制氮氧分离; 高温下吸附影响不显著.     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究(Ⅰ)──低温氧等离子体改性条件对亲和膜结构与吸附性能的影响

用低温氧等离子体方法对聚丙烯微孔膜表面进行改性.扫描电镜、红外光谱和光电子能谱综合分析结果表明,膜表面上产生了-OH、-COOH和C=O等极性基团,这些基团可被活化和偶联制亲和膜.所制备的Cu²⁺离子金属螯合亲和膜用于对溶菌酶的吸附,在20min和68W的最佳条件下,制成的亲和膜对溶菌酶的吸附量为8μg/cm².     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究(Ⅱ)──不同金属螯合亲和膜对溶菌酶的吸附性能

采用低温氧或氨等离子体法改性聚丙烯微孔膜,基于等离子体改性膜的活化、偶联及螯合过程的机理,制备了Fe³⁺,Ni²⁺,Cu²⁺和Zn²⁺等金属离子螯合亲和膜,并用于溶菌酶的吸-脱附实验.实验结果表明,Ni²⁺和Cu²⁺离子螯合亲和膜对溶菌酶具有较高的吸附量,螯合过程中采用氯化物盐溶液制得的膜对溶菌酶吸附量比采用硫酸盐溶液制得的膜的吸附量高.两种膜的重复吸-脱附性能相近,而Fe³⁺螯合亲和膜基本上不能用于重复吸-脱附实验.采用补充金属螯合离子,能部分恢复亲和膜对溶菌酶的吸附量,是实现亲和膜重复使用的有效方法.     

退火处理对LaFeO3/Pd复合薄膜微观结构和在碱液中电化学行为的影响

采用射频磁控溅射装置在Si(111)衬底上分别制备了Pd单膜、LaFeO3单膜和LaFeO3/Pd复合薄膜,利用XRD,SEM,EDS,XPS和电化学测试方法研究了退火处理对LaFeO3/Pd薄膜材料的相结构、形貌、化学组成以及电化学性能的影响。研究结果表明:未退火的溅态LaFeO3薄膜呈无序非晶态结构,随退火温度升高,600℃退火1 h后LaFeO3薄膜晶化为钙钛矿型正交结构,此时薄膜晶粒尺寸呈增大趋势;800℃退火时,随退火时间增加,薄膜晶粒尺寸变化不明显,退火前LaFeO3薄膜表面平整、致密,退火后薄膜表面出现裂纹。XPS分析表明,LaFeO3薄膜中的氧以晶格氧、化学吸附氧和物理吸附氧三种结合状态形式存在,退火后LaFeO3薄膜中化学吸附氧转变为晶格氧。电化学测试结果表明,Pd膜电极和LaFeO3膜电极放电容量很低(3.9~19 mAh·g-1),而LaFeO3/Pd复合薄膜在退火前后的电极放电容量分别达到50和180.7 mAh·g-1,LaFeO3单膜和LaFeO3/Pd复合薄膜电极的交换电流密度I0分别为为3.36和590.51 mA·g-1。镀Pd后能极大改善和提高LaFeO3/Pd复合膜电极的电催化活性和电化学放电容量。     

La2NiO4复合氧化物的合成及性能研究

采用Ｐｅｃｈｉｎｉ方法合成了Ｌａ２ＮｉＯ４＋δ粉体，通过ＸＲＤ，Ｏ２－ＴＰＤ，ＴＧ和ＸＰＳ等对其物相、氧非计量以及表面状态进行了表征；制备了Ｌａ２ＮｉＯ４＋δ致密透氧膜并考察了其透氧性能。发现其非计量氧的脱出、补充有可逆性；表面吸附氧可转化成Ｏ＾δ－物种，在膜操作状态下，通过体相填隙氧浓差扩散到低氧压侧，以Ｏ２形式脱出，实现连续透氧。     

合金元素Nd对Pb-Ag阳极在H_2SO_4溶液中电化学行为的影响（英文）

采用循环伏安、线性扫描、电化学阻抗和环境扫描电镜对比研究了Pb-Ag和Pb-Ag-Nd阳极的阳极膜和析氧反应.结果表明,合金元素Nd促进了Pb/PbOn/PbSO4(1≤n2)膜层的生长.在高极化电位区间(高于1.20V(vs Hg/Hg2SO4/饱和K2SO4溶液)),Nd有利于低价铅的化合物(PbOn,PbSO4)向α-PbO2和β-PbO2转变.此外,环境扫描电镜形貌和线性扫描分析证明Pb-Ag-Nd表面生成的阳极膜较Pb-Ag的阳极膜更厚且更致密.因此,Pb-Ag-Nd阳极表面的阳极膜可以给合金基底提供更好的保护.另一方面,电化学阻抗测试揭示了两种阳极的析氧反应均受中间产物的形成和吸附控制.Nd可以降低阳极膜/电解液界面处中间产物的吸附阻抗且增加中间产物的覆盖率,从而提高析氧反应活性.综上所述,合金元素Nd可提高Pb-Ag阳极的耐腐蚀性,降低阳极电位进而起到节能降耗的作用.     

氧乙烯数对辛基苯酚聚氧乙烯醚表面扩张粘弹性质的影响

研究了非离子表面活性剂辛基苯酚聚氧乙烯醚TX-100、TX-102和TX-165(平均氧乙烯数依次为10、12、16)水溶液的表面扩张粘弹性质, 考察了氧乙烯数变化对表面吸附膜特性的影响. 研究结果表明, 随着氧乙烯数的增大, 表面膜表现出较大的模量和较强的弹性. 这是由于较长氧乙烯链在表面上的“平躺”产生较慢的弛豫过程造成的.     

Ru膜上Pt层的自发沉积及其在电化学表面增强红外光谱中的应用

采用自发沉积法在Ru膜上生成超薄Pt层(简称Ru/Pt膜), 即在开路状态下将电化学还原后的Ru膜浸于除去氧的H2PtCl6溶液中进行自发沉积. 电化学伏安法测量表明, 随着电还原-自发沉积循环次数的增加, 该Ru/Pt膜电极所含Pt组分增加, 且CO吸附层的电氧化峰电位较Pt膜电极上的明显负移. 应用现场衰减全反射表面增强红外光谱法(ATR-SEIRAS)可轻易检测到在该膜电极Pt和Ru位上吸附CO的振动谱峰. 所制Ru/Pt膜电极不仅对CO的电催化氧化具有协同效应, 还可应用于现场ATR-SEIRAS的研究中.     

纳米钛薄膜的XPS研究

用 XPS分析了三种纳米钛薄膜表面和经 Ar 溅射后内部碳、氧、氮、钛等的含量和化学态。发现三种薄膜表面碳、氧含量完全一致 ,碳为石墨态 ,氧为吸附态的水。薄膜内部碳、氧、氮的化学态主要为 Ti C、Ti O2 、Ti N。随着分析深度的增加 ,薄膜内金属钛的原子百分比浓度不断增加并逐渐趋于恒定。镀膜时真空度的提高有利于减少碳、氧、氮的污染。Ar 溅射所镀的膜与电子枪所镀的膜相比 ,晶粒尺寸小 ,在表面至浅表层内氧的含量有明显差异。     

Transport of ionic species through functionalized poly(vinylbenzyl chloride) membranes

Solid polymeric membranes of poly(vinylbenzyl chloride) (VBC), lightly crosslinked with divinyl benzene, were incompletely reacted such that a fraction of the benzyl chlorines in different membranes was replaced with either dimethyl phosphonate esters (MPE) or triethyl ammonium chloride groups (QA). This work was conducted in an effort to investigate ionic transport through charged and uncharged membranes and to develop fixed site carrier membranes to facilitate the transport of selected metal ions from an aqueous feed stream to a concentrated acid receiving stream. Bulk solution flow does not occur through these membranes. Instead, solute diffusion occurs through the membrane matrix. The effects of hydrogen ion gradient, metal ion identity and charge, reactive site type, acid type, and ionic strength on metal ion transport were investigated. Results are also presented on the effect of membrane orientation and pretreatment (swelling) on metal ion transport. Facilitated transport was investigated through the testing of membranes with varying MPE percent functionalization. The results presented compare the metal ion transport rate to the functionalization of the membranes.     

Development of urethane acrylate composite ion-exchange membranes and their electrochemical characterization

With the objective of introducing antifouling characteristics into interpolymer types of cation and anion exchange membranes, the surface of these membranes was coated with a 12-microm-thick urethane acrylate layer and was cured by UV radiation of wavelengths 308 and 172 nm under a complete inert atmosphere. Different urethane acrylate composite ion exchange membranes developed were characterized in NaCl solution by measuring their ion-exchange capacity, volume fraction of water, contact angle with water, membrane conductance, and membrane potential. It was found that the electrochemical transport properties of urethane acrylate composite cation-exchange membranes were increased due to resonance stabilization of the urethane group, which acts as a weak acid and dissociates as a negatively charged urethane ion and a positively charged proton. This contributes toward the net charge density of the membrane matrix responsible for enhanced selectivity and conductivity, while for urethane acrylate composite anion-exchange membranes reduction in net charge density was responsible for reduction in electrochemical transport properties. Counterion transport number, permselectivity, and counterion diffusion coefficient values for these membranes were also estimated. Experiments were also carried out in higher homologs of sodium carboxylate solutions in order to observe the fouling tendencies of these membranes. It was concluded that it is possible to obtain antifouling characteristics of ion-exchange membranes by coating and curing thin hydrophilic layers of urethane acrylate on their surfaces without sacrificing their electrochemical transport properties.     

合成高分子膜透气速率的温度依赖性

近年来以气体选择性分离为目的的合成高分子膜的研究取得了巨大的进步。气体分离膜的两个基本性能参数是透气速率J及选择系数α。同一个膜,在较高温度使用时,往往是J值增大,α值下降,因此选择适当地操作温度,以便得到最佳的J-α搭配是很重要的。本文讨论了甲基硅橡胶(MSR)、天然橡胶(NR)、乙丙橡胶(EPR)、聚乙烯(PE)、聚(4-甲基戊烯-1)(TPX)等材料的均质膜或复合膜,在不同温度下的氧、氮透过速率,计算了各种膜材料的氧、氮表观透过活化能,并对其本质进行了探讨。     

一种具有识别运输钠离子的离子通道膜的制备

以三氯甲烷为溶剂,用3-异氰酸基丙基三乙氧基硅烷和对氨基苯酚合成得到一种自组装杂化材料——3-(脲基酚基)丙基三乙氧基硅烷.采用FTIR、XPRD分析方法对该化合物的结构以及晶体形态进行了表征.利用旋涂法和共混法分别制备离子通道膜,采用ATR-FTIR和SEM分析手段表征膜的化学结构和形态结构,并通过自制的膜运输实验装置测定膜的传输性能并提出了相应的传输机理.实验结果表明,两种方式所得的离子通道膜表面是致密无孔的,致密层厚度为8～10μm左右;采用共混法制得的离子通道膜的传输速度较旋涂法快.离子通道是杂化材料通过分子自组装形成的,该通道可以识别并运输Na+.     

Correlation Between Structure and Transport Properties of Polymeric Membranes for Immunoisolation

Laboratory-made asymmetric polyurethane membranes designed for immunoisolation were investigated. Two types of EK and ES membranes were prepared in different spinning conditions. The membrane structure was characterised by the skin pore radius measurements using differential scanning calorimetry (DSC). Diffusive transport properties of membranes were determined by in vitro method for albumin and creatinine. The scanning electron microscopy (SEM) was applied to study the morphology of membranes. It has been found that the DSC technique is a useful tool for the evaluation of pore radii in the skin layer for PU membranes. Calculated pore radii were in the range from 1.95 to 2.47 nm for the EK and ES types. A correlation between the skin pore radii and the transport properties was not found in this case of investigated membranes. However, the transport properties data can serve for the estimation of selectivity of membranes. Thus, the selectivity of membranes for solutes of various molecular size was estimated from the D _m/D _w ratio of diffusion coefficients for albumin and creatinine. The SEM micrographs reveal the finger-like internal structure of capillary membranes, as well as various skin thickness. This revised version was published online in July 2006 with corrections to the Cover Date.     

Electrochemical Parameters of Heterogeneous Bipolar Membranes: Dependence on the Structure and Nature of Monopolar Layers

The current–voltage curves, transport numbers of ions, and electrochemical impedance spectra are obtained for pilot samples of heterogeneous bipolar membranes synthesized from cation- and anion-exchange membranes. In the synthesis, the composition of the monopolar layers of membranes was varied or a catalyst was introduced into them. The voltage drop and the frequency spectra at the pilot membranes are close to those for industrial membrane MB-3. The transport numbers of co-ions in the pilot membranes are smaller and those of the hydrogen and hydroxyl ions are larger than in MB-3. The effective water dissociation constants in the pilot membranes, calculated from the impedance spectra, are close to those of MB-3.     

聚合物-卟啉钴复合膜的氧气促进输送性能

综述了聚合物－卟啉钴复合膜的氧气促进输送性能。讨论了卟啉钴的结构及与氧的结合性能，聚合物－卟啉钴复合膜的氧气促进输送特性，影响聚合物－卟啉钴复合膜氧气透过性能的因素及卟啉钴的不可逆氧化反应机理。     

Factors influencing the transport of tryptophan hydrochloride through supported liquid membranes containing macrocyclic carriers

Commercially available PTFE membranes were used as a support for liquid membranes in amino acid transport. Using tryptophan as a model amino acid, the influence of the type of organic liquid, kind of macrocyclic carrier and counter-ion on transport efficiency was examined. These studies show the strong influence of the kind of the counter-ion co-transported with amino acid cation, and the type of macrocyclic carrier used on the transport efficiency. The transport efficiency depends also on the pH of the source phase and on the nature of the organic liquid used as a membrane solvent. Liquid membranes supported on commercial porous-PTFE-membranes with hydrophobic solvents are stable for more than two months, while those with more hydrophilic solvents, for more than 30 days. The use of dodecylbenzenesulfonic acid as a counter-ion results in the highest flux of tryptophan, but in this case, the stability of membranes appeared to be five times lower.     

Smart zwitterionic membranes with on/off behavior for protein transport

Poly(acrylonitrile) (PAN)-based zwitterionic membranes, composed of PAN and poly( N, N-dimethyl- N-methacryloxyethyl- N-(3-sulfopropyl) copolymer, are electrolyte-sensitive smart membranes. The hydrophilicity was increased and protein adsorption was remarkably decreased for the membranes in response to environmental stimuli. FTIR spectroscopic analysis directly provided molecular-level observation of the enhanced dissociation and hydration of zwitterionic sulfobetaine dipoles at higher electrolyte concentrations. The smart PAN-based zwitterionic membranes can close or open channels for protein transport under different NaCl concentrations. The electrolyte-sensitive switch of on/off behavior for protein transport is reversible.     

Spray-coated and solution-cast ethylcellulose pseudolatex membranes

Membranes of dibutyl sebacate (DBS) plasticized ethylcellulose pseudolatex were prepared by spray-coating and solution-casting methods for the studies of their transport and mechanical properties. The structure of sprayed membranes was more porous than that of cast membranes, so the sprayed membranes were more permeable than the cast membranes. The permeabilities of drug or water vapor through sprayed membranes decreased with increasing plasticizer concentration; on the contrary, those through cast membranes increased with increasing plasticizer concentration. The diffusion through pores accounts for the transport through sprayed membranes, while the solution–diffusion through plasticized polymer phase may become an important role for that through the cast membranes. Mechanically, the sprayed membranes were harder and more brittle than the cast membranes of similar formulation, but membranes prepared from both methods possessed similar breaking tensile strength. The tensile strength and Young's modulus were reduced and the elongation was improved with increasing plasticizer concentration for both kinds of membranes. The sprayed membranes would become less permeable and tougher after the post thermal treatment as the degree of coalescence between the latex particles in the membranes was enhanced.