新型燃料电池质子交换膜的研究进展

由于当前所使用的质子交换膜材料存在成本高、无法高温操作和不够环保等缺点，开发新型的成本低、性能高的质子交换膜越来越引起人们的重视．对于新型质子交换膜的研制主要体现在两个方面，一个是对于全氟磺酸型膜的改进和增强，包括加入支撑材料或掺杂增强材料等方法；另一个是彻底抛开全氟树脂，开发新型的质子交换膜材料，其中包括直接磺化、直接聚合、接枝、掺杂等制备方法，简要评述了这些方法的优缺点和这些膜材料的性能，并附以实例说明．     

燃料电池用质子交换膜的研究进展

对燃料电池用质子交换膜的研究进展进行了简要的概述，特别是从膜材料角度分类．较详细的介绍了全氟化质子交换膜，部分氟化质子交换膜，接枝、交联、共混型质子交换膜等的特性及最新的研究状况，并对其发展前景进行了探讨．     

质子交换膜的交联改性研究进展

燃料电池的应用需要性能优越的质子交换膜,而目前广泛使用的全氟磺酸膜以及其他类型的质子交换膜普遍都存在着热稳定性较差、溶涨过大、阻醇性能不理想等问题,这些缺点可用交联的方法得到一定程度的改善.综述了近年来交联改性质子交换膜的研究进展,并对其交联方法、改性效果进行了详细的讨论.     

燃料电池用含氟质子交换膜的研究现状

简要介绍了燃料电池的定义、分类及其特点.介绍了全氟磺酸质子交换膜中质子传输机理,按质子交换膜材料的不同,分类回顾了近年来全氟磺酸质子交换膜、部分含氟质子交换膜等领域的研究进展,并展望了今后的研究趋势.     

燃料电池用磺化聚醚醚酮质子交换膜的研究

通过浓硫酸磺化法制备了具有不同磺化程度的磺化聚醚醚酮(SPEEK),并对此种质子交换膜进行了物化性能和H2／O2质子交换膜燃料电池性能研究,实验结果表明,SPEEK膜具有较理想的力学稳定性和气体渗透率,它的微观结构和质子传导性能与Nafion膜有所不同,经过其H2／O2质子交换膜燃料电池的性能研究,SPEEK膜能够保证电池在200h内稳定运行,有希望成为PEMFC用质子交换膜材料。     

质子交换膜的研究现状与进展

简述了质子交换膜燃料电池中质子交换膜的质子传导机理；讨论了目前质子交换膜存在的甲醇渗透、耐温性等共性问题，就如何解决这些问题进行了评述，同时，论述了质子交换膜的研究开发现状及其发展前景。     

质子交换膜在燃料电池中的应用

质子交换膜（ＰＥＭ）燃料电池以质子交换膜为电解质，燃料电池的性能强烈地依赖于质子交换膜的特性。本文综述ＰＥＭ电池对质子交换膜的技术要求及该膜的检测和在燃料电池中的应用情况。     

燃料电池质子交换膜的研究进展

本文从质子交换膜的发展入手 ,指出全氟磺酸型质子交换膜是目前最适合燃料电池的膜材料 ,并对其结构特点及优缺点进行了重点分析 ,论述了目前质子交换膜的发展趋势     

化学交联法在质子交换膜制备中的应用

化学交联是提高质子交换膜性能的一种有效方法。交联质子交换膜具有较低的水溶胀性、甲醇渗透性,以及较高的热、力学稳定性。使用化学交联法制备质子交换膜时,通常采用交联聚合物磺化法、磺化聚合物交联法和共混聚合物交联法等三种方法。采用不同方法交联时,交联活性点的选取各不相同,制备的交联质子交换膜性能也有差异。深入研究交联程度、离子交换容量、交联剂种类等不同制备条件对交联膜的微观结构及性能的影响,才能使交联质子交换膜的综合性能得到优化。     

燃料电池用质子交换膜的研究进展

质子交换膜是质子交换膜燃料电池(PEMFC)的和绝缘电子的作用,其性能和寿命直接决定电池的性能和寿命.从膜材料的角度分类,综述了质子交换膜燃料电池用主链含氟聚合物膜、元素有机聚合物膜以及芳香族碳氢化合物膜的特性和研究现状.     

燃料电池质子交换膜的研究现状

目前燃料电池质子交换膜的研究正引起人们越来越多的关注,质子交换膜是质子交换膜燃料电池的核心组件.较详细地介绍了全氟化质子交换膜,部分氟化质子交换膜,有机/无机纳米复合质子交换膜,新型无氟化质子交换膜的性能及最新研究状况,最后对其发展前景进行了探讨.     

Fabrication and in vitro evaluation of stable collagen/hyaluronic acid biomimetic multilayer on titanium coatings

Layer-by-layer (LBL) self-assembly technique has been proved to be a highly effective method to immobilize the main components of the extracellular matrix such as collagen and hyaluronic acid on titanium-based implants and form a polyelectrolyte multilayer (PEM) film by electrostatic interaction. However, the formed PEM film is unstable in the physiological environment and affects the long-time effectiveness of PEM film. In this study, a modified LBL technology has been developed to fabricate a stable collagen/hyaluronic acid (Col/HA) PEM film on titanium coating (TC) by introducing covalent immobilization. Scanning electron microscopy, diffuse reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the PEM film. Results of Sirius red staining demonstrated that the chemical stability of PEM film was greatly improved by covalent cross-linking. Cell culture assays further illustrated that the functions of human mesenchymal stem cells, such as attachment, spreading, proliferation and differentiation, were obviously enhanced by the covalently immobilized Col/HA PEM on TCs compared with the absorbed Col/HA PEM. The improved stability and biological properties of the Col/HA PEM covalently immobilized TC may be beneficial to the early osseointegration of the implants.     

等离子体发射监控系统参与的中频孪生反应磁控溅射沉积TiO_2薄膜的实验研究

在一个孪生靶实验装置上进行了中频反应磁控溅射沉积TiO_2薄膜的工艺实验.得到了一组真实的反应溅射TiO_2薄膜的沉积速率和真空与反应气体流量之间关系的迟滞曲线(无等离子体发射监控系统Plasma Emission Monitoring,PEM)参与.介绍了PEM参与下的反应溅射TiO_2的一些实验现象和结果,此时TiO_2的沉积速率与PEM设定值呈很好的线性关系,反应溅射可以稳定在过渡态的任一工作点.设定值是PEM控制系统最关键的参数,直接决定着控制的可靠性、反应溅射速率以及薄膜的微观结构.结果表明,为了得到标准化学配比的反应物,PEM的设定值不能超过某个极限值.要在保证化学配比也就是反应物的成分或结构的前提下提高沉积速率才有意义.     

高温质子交换膜的研究进展

高温质子交换膜能解决传统燃料电池电极催化剂CO中毒、复杂的水热管理等问题,成为当今燃料电池发展研究的焦点。结合质子交换膜的结构与性能之间的关系,分析了分子结构设计对膜性能的重要影响,总结了接枝型、复合型质子交换膜、新型耐热交换膜的研究现状。对有机/无机粒子复合膜材料,磷酸掺杂聚苯并咪唑(PBI)、聚芳硫醚砜(PASS)等类型膜材料进行了评述,为高温质子交换膜的研究指明了方向。     

供应商部分主导私人电子市场Stackelberg博弈

私人电子市场(PEM)是一个封闭的网络,具有高度灵敏的信息共享、高协调能力及保密性强等优点.探讨"一对二"结构下的供应链Stackelberg博弈,在构建PEM后供应商主导地位将减弱,据此分析了三种情况下供应商的批发价格及供应链各变量的变化规律.得出结论是,当供应商降为部分主导时,供应链效率最低, PEM拥有者的采购价格最低.随后通过数值分析得到,随着生产成本两项参数的同时增大,PEM拥有者的最优订货量、非PEM拥有者的最优订货量和最优收益、供应商的最优收益等均逐渐减小,而PEM拥有者的最优收益却逐渐增大.     

Selective permeation of hydrogen peroxide through polyelectrolyte multilayer films and its use for amperometric biosensors.

A platinum electrode was coated with polyelectrolyte multilayer (PEM) films to prepare an amperometric hydrogen peroxide sensor which can be used in the presence of possible interferences such as ascorbic acid, uric acid, and acetaminophen. The PEM films were prepared on the surface of a Pt disk electrode by an alternate deposition of polycation and polyanion from the aqueous solutions through electrostatic force of attraction. The Pt electrodes coated with a poly(allylamine)/poly(vinyl sulfate) or poly(allylamine)/poly(styrenesulfonate) film were used successfully for detecting H2O2 selectively in the presence of the possible interfering agents. It was suggested that H2O2 can diffuse into the PEM film smoothly while the ascorbic acid, uric acid, and acetaminophen cannot penetrate the film by a size exclusion mechanism. On the other hand, the electrodes coated with PEM films containing poly(ethyleneimine) or poly(diallyldimethylammonium chloride) were not useful for the selective determination of H2O2. The results were rationalized based on the different permeability of the films due to the different molecular density or packing in the PEM films. The PEM film-coated electrode was useful for constructing glucose biosensors by coupling with glucose oxidase.     

PEM fuel cell stack sealing using silicone elastomers

The economic viabilty of proton-exchange membrane (PEM) fuel cells requires significant reductions in the cost of assembling and sealing the PEM stack. In addition, the stack sealing system or method must last the life of the stack, and is often used to enhance the structural strength of the stack and provide performance-enhancing functionality. This article discusses the findings and results of studies that are part of Dow Corning's PEM fuel cell stack sealing programme.     

Polyelectrolyte multilayers for bio‐applications: recent advancements

The synergistic relationship between structure and the bulk properties of polyelectrolyte multilayer (PEM) films has generated tremendous interest in their application for loading and release of bioactive species. Layer‐by‐layer assembly is the simplest, cost effective process for fabrication of such PEMs films, leading to one of the most widely accepted platforms for incorporating biological molecules with nanometre precision. The bulk reservoir properties of PEM films render them a potential candidate for applications such as biosensing, drug delivery and tissue engineering. Various biomolecules such as proteins, DNA, RNA or other desired molecules can be incorporated into the PEM stack via electrostatic interactions and various other secondary interactions such as hydrophobic interactions. The location and availability of the biological molecules within the PEM stack mediates its applicability in various fields of biomedical engineering such as programmed drug delivery. The development of advanced technologies for biomedical applications using PEM films has seen rapid progress recently. This review briefly summarises the recent successes of PEM being utilised for diverse bio‐applications.Inspec keywords: polymer electrolytes, multilayers, polymer films, molecular biophysics, biomedical materials, biochemistryOther keywords: bioapplications, polyelectrolyte multilayer films, bioactive species, layer‐by‐layer assembly, biological molecules, biosensing, drug delivery, tissue engineering, biomolecules, proteins, DNA, RNA, electrostatic interactions, secondary interactions, hydrophobic interactions, biomedical engineering, programmed drug delivery, biomedical applications, PEM films