全钒氧化还原液流电池用Nafion/有机硅复合膜

采用原位化学反应的方法制备了Nafion/有机硅复合膜, 并对所制备复合膜的离子交换容量(IEC)、电导率和水渗透率等进行了测试. 结果表明, 所制备复合膜具有优异的阻水性能. 以Nafion/有机硅复合膜作为离子交换膜的钒电池的库仑效率(CE)和能量效率(EE)都得到了大幅度提高. 此外, 以所制备复合膜为离子交换膜的VRB单电池充放电80次后性能几乎无衰减, 说明所制备Nafion/有机硅复合膜即使在强酸和强氧化性的钒电池体系中也可以稳定使用, 表明Nafion/有机硅复合膜是一种性能优异的适用于全钒氧化还原液流电池的新型质子交换膜.     

Fabrication and analytical applications of hybrid mesoporous membranes.

Recently, a hybrid mesoporous membrane composed of surfactant-templated mesoporous silica inside a porous anodic alumina membrane has been developed. Since this membrane allows the use of columnar silica-mesopores (silica-nanochannels) as nanofluidic channels, separation of molecules can be realized by mass transport through the silica-nanochannel with molecular dimensions. Here, we review the methods to fabricate the hybrid mesoporous membranes, their structural features, and the analytical applications of hybrid mesoporous membranes.     

质子化非那吡啶在功能化复合介孔膜修饰的液/液界面上的转移反应

采用循环伏安法和差分脉冲伏安法考察了临床药物盐酸非那吡啶在功能化复合介孔膜修饰的水/1,6-二氯己烷(W/DCH)界面上的转移行为. 研究结果表明, 盐酸非那吡啶中的非那吡啶(PAP) 可在酸性条件下发生质子化形成非那吡啶阳离子(HPAP⁺)并在该界面上发生转移. 根据循环伏安曲线峰电流与扫描速率的关系以及Randles-Sev$\check{c}$ik 方程, 计算得到HPAP⁺在复合介孔膜内水相中的扩散系数为5.14×10^-8 cm²/s. 研究发现, 相对于空白膜修饰的W/DCH界面, 该复合介孔膜修饰的W/DCH界面可增强非那吡啶阳离子转移时的电流响应, 并提升非那吡啶阳离子的检测性能. 另外, 利用液/液界面电化学方法绘制了非那吡啶在功能化复合介孔膜修饰的W/DCH界面上的离子分布图, 从而得到非那吡啶在该界面上不同条件下的分布情况及其分配系数和吉布斯转移自由能.     

Synthesis and characterization of uniform alumina-mesoporous silica hybrid membranes

The synthesis and characterization of alumina-mesoporous silica (alumina-MS) hybrid membranes are reported. The hybrids are formed using a variation of the evaporative-induced self-assembly (EISA) process reported by Hayward et al. (Langmuir 2004, 20, 5998) based on dip coating of an Anopore 200 nm membrane with a Brij-56/TEOS/HCl/H2O solution. Numerous analytical methods are used to probe both the hybrid material and the silica phase after dissolution of the Anopore substrate. Most importantly, He/N2 permeation measurements show that the effective pore size of the membrane can be tuned from 20 to 5 nm based on the number of dip-coating cycles used. The observed He/N2 permselectivity of 2.7 +/- 0.11 is nearly identical to the theoretical value obtained (2.65) assuming Knudsen diffusion dominates. The selectivity of these membranes is higher than that of most commercial "5 nm" membranes (2.29), which is ascribed to the lack of pinhole defects in the materials reported here. The hybrid membranes as well as the silica obtained after dissolution of the Anopore substrate have been characterized using scanning and transmission electron microscopy and X-ray diffraction. Those results indicate that the silica deposited in the Anopore membrane possesses uniform pores approximately 5 nm in size, consistent with the permeation studies. The current work presents an alternative approach to materials that possess many of the properties of mesoporous silica thin films (i.e., pores of controlled size and topology) without the difficulty of growing mesoporous silica thin films on porous supports.     

二氧化硅/聚乙烯醇杂化电纺纤维膜的制备与结构形态

用溶胶-凝胶(Sol-Gel)法制备了不同二氧化硅含量的PVA/SiO2杂化纺丝液,将其电纺成纤维膜.XRD结果表明,杂化电纺纤维膜的结晶度较纯PVA电纺纤维膜小;FTIR证实了PVA的羟基与正硅酸乙酯水解后的羟基发生了缩合反应,杂化电纺纤维膜是以网络结构形式相结合的;FESEM表明,PVA/SiO2质量比为4∶1时,纤维光滑,分散比较均匀.随着二氧化硅含量的增加,纤维直径变细,纺锤形珠节结构增多.加入金属盐NaCl和MgCl2后,纤维直径变细,圆形珠节增多.从理论上分析了纤维膜结构形态的形成机理.     

Polycaprolactone membranes reinforced by toughened sol–gel produced silica networks

The aim of this work is to develop polycaprolactone based porous materials with improved mechanical performance to be used in bone repair. The hybrid membranes consist in a polymeric porous material in which the pore walls are coated by a silica thin layer. Silica coating increases membrane stiffness with respect to pure polymer but in addition filling the pores of the polymer with a silica phase improves bioactivity due to the delivery of silica ions in the neighborhood of the material in vivo. Nevertheless silica network, even that produced by sol–gel, might be too stiff and brittle what is not desirable for its performance as a coating. In this work we produced a toughened silica coating adding chitosan and 3-glycidoxypropyltrimethoxysilane (GPTMS) to the precursor solution looking for having polymer chains linked by covalent bonding to the silica network. Hybrid polymer–silica coating was produced by in situ sol–gel reaction using Tetraethyl orthosilicate (TEOS), GPTMS and chitosan. Chemical reaction between amine groups of chitosan chains and epoxy groups of GPTMS allowed covalent bonding of polymer chains to the silica network. Physical properties of the hybrid membranes were characterized and cell attachment of MC3T3-E1 pre-osteoblastic cells on the surface of these supports was assessed.     

Evaluation of hybrid silica sols for stable microporous membranes using high-throughput screening

Microporous membranes are a promising option for energy-efficient molecular separations. Long-term hydrothermal stability of the membrane material is of prime importance for several industrial processes. Here, a short overview of silica-based membrane materials and their hydrothermal stability is presented. Following this, the development of a series of organic–inorganic hybrid silica sols is described, based on α,ω-bis(triethoxysilyl)-precursors with bridging methane, ethane, propane, and benzene groups. High-throughput screening was used to scan a range of sol parameters, followed by membrane preparation from the most promising sols. These organic–inorganic hybrid silica (HybSi^®) membranes were used in dewatering of lower alcohols by pervaporation. Separation factors up to 200 were found for ethanol/water mixtures, and up to 23 for methanol/water mixtures. Modest permselectivity values for hydrogen over nitrogen were found, ranging up to 20.7 for the shortest bridging group. It was concluded that the length of the organic bridge has a clear effect on the pore size distribution and the selectivity of the membrane.     

Structural characterization of silica modified polyimide membranes

Polyimide and hybrid polyimide‐siloxane were synthesized by polycondensation, imidization, and sol‐gel reaction. The polyimides were prepared from pyromellitic dianhydride (PMDA) and 4,4‐oxydianiline (ODA) in N‐methyl‐2‐pyrollidone (NMP). Trimethoxyvinyl silane (TMVS) was used as a source of silica. Their surface morphologies, structures and thermal performances were determined using scanning electron microscopy (SEM), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the silica particles were finely and rather homogeneously dispersed in polymers. The glass transition temperature (T_g) of hybrid membrane materials increased with the increasing silica content. TGA analysis showed that polyimides were thermally stable with silica. Modified polyimide‐siloxane films, thermal characteristics were found to be better than the polyimide films without silica. Copyright © 2006 John Wiley & Sons, Ltd.     

Novel polyester/SiO2 nanocomposite membranes: Synthesis,properties and morphological studies

In this paper, a new type of soluble polyester/silica (PE/SiO₂) hybrid was prepared by the ultrasonic irradiation process. The coupling agent γ-glycidyloxypropyltrimethoxysilane (GOTMS) was chosen to enhance the compatibility between the polyester (PE) and silica (SiO₂). Furthermore, the effects of the coupling agent on the morphologies and properties of the PE/SiO₂ hybrids were investigated using UV-vis and FT-IR spectroscopies and FE-SEM. The densities and solubilities of the PE/SiO₂ hybrids were also measured. The results show that the size of the silica particle was markedly reduced by the introduction of the coupling agent, which made the PE/SiO₂ hybrid films become transparent. Furthermore, thermal stability, residual solvent in the membrane film and structural ruination of membranes were analyzed by thermal gravimetric analysis (TGA). The effects of SiO₂ nanoparticles on the glass transition temperature (T_g) of the prepared nanocomposites were studied by differential scanning calorimetry (DSC). Moreover, their mechanical properties were also characterized. It can be observed that the Young's moduli (E) of the hybrid films increase linearly with the silica content. The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO₂ nanoparticles to the polymeric membrane structure increased the permeability of the membranes.     

Hybrids of colloidal silica and waterborne polyurethane

Waterborne polyurethane (WPU) was synthesized and followed by adding colloidal silica to prepare WPU-silica hybrids. The silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results revealed that the viscosity of these hybrid solutions increased with increasing silica content and resulted in the aggregation of silica particle in the hybrid films. The latter result was evidenced by SEM examination. The effect of interaction between silica particle and urethane polymer chains is more significant with increasing silica content. The prepared hybrid films show much better thermal stability and mechanical properties than pure WPU. The optical transparence did not linearly decrease with increasing the silica fraction in the hybrid thin film. At below 20% silica content, the film transparence decreased with increasing silica content; the converse is true at above 20% silica content. These results showed that the prepared hybrid films demonstrated tunable transparence with the silica fraction in the films.     

Biomimetic synthesis of raspberry-like hybrid polymer–silica core–shell nanoparticles by templating colloidal particles with hairy polyamine shell

The nanoparticles composed of polystyrene core and poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairy shell were used as colloidal templates for in situ silica mineralization, allowing the well-controlled synthesis of hybrid silica core–shell nanoparticles with raspberry-like morphology and hollow silica nanoparticles by subsequent calcination. Silica deposition was performed by simply stirring a mixture of the polymeric core–shell particles in isopropanol, tetramethyl orthosilicate (TMOS) and water at 25 °C for 2.5 h. No experimental evidence was found for nontemplated silica formation, which indicated that silica deposition occurred exclusively in the PDEA shell and formed PDEA–silica hybrid shell. The resulting hybrid silica core–shell particles were characterized by transmission electron microscopy (TEM), thermogravimetry, aqueous electrophoresis, and X-ray photoelectron spectroscopy. TEM studies indicated that the hybrid particles have well-defined core–shell structure with raspberry morphology after silica deposition. We found that the surface nanostructure of hybrid nanoparticles and the composition distribution of PDEA–silica hybrid shell could be well controlled by adjusting the silicification conditions. These new hybrid core–shell nanoparticles and hollow silica nanoparticles would have potential applications for high-performance coatings, encapsulation and delivery of active organic molecules.     

Radiation-induced polymerization and grafting of β(−)pinene on silica surface

Poly-β-pinene (pBp) was obtained on silica surface by γ radiation-induced polymerization of β(−)pinene in presence of silica gel with a specific surface area of 300 m²/g. Different radiation doses were employed in the range 50–332 kGy. The pBp–silica hybrid samples obtained have been characterized by FT-IR spectroscopy and the amount of pBp on silica surface has been determined both by gravimetric and TGA measurements. The fraction of pBp chemically grafted on silica surface has been determined by the extraction of the pBp–silica hybrid with boiling toluene and was found to be 10–20% of the total pBp formed on silica surface. The optical activity of pBp extracted from the hybrid was studied by polarimetric measurements and found slightly lower than the typical specific optical rotation of pBp polymerized in bulk with radiation. The thermal stability of the pBp–silica hybrid materials was studied by thermogravimetric and differential thermal analysis. The results show lower thermal stability for the pBp–silica hybrid in comparison to pure pBp. Evidently, silica catalyzes the thermal decomposition of pBp at lower temperatures. Use of the pBp–silica hybrid as stationary phase for liquid chromatography for chiral separations has been proposed.     

负载型聚酰亚胺-二氧化硅-银杂化膜的制备和表征

采用溶胶凝胶法制备了硅藻莫来石负载的SiO2(SiO2KM)负载的聚酰亚胺二氧化硅银杂化膜,采用IR、TGA、SEM、XRD、氮吸附、气体渗透性能测量等方法对膜的性能进行了表征.银的加入使杂化溶胶的粘度增大,膜孔径增大,孔径分布弥散;二氧化硅在杂化膜中以无定型存在,银以氯化银的形式存在;Ag+和聚酰亚胺中的氮以配位键络合在一起,丙烯通过双键吸附在Ag+上;杂化膜热稳定性随二氧化硅的加入而增加,随银的加入而降低.丙烯丙烷在杂化膜上的分离因子为3.54～4.1,银的加入对丙烯的传输有明显的促进作用.     

Interaction and Microstructure of Polyurethane/Silica Hybrid Films Prepared by Sol-Gel Process

The polyester/silica hybrid resins and their hybrid polyurethanes were prepared via in situ (IS) or blending (BL) method using different silica sols. The effects of preparation methods, silica type and content on the interaction and microstructure of polymer/silica hybrid materials were investigated by FTIR, viscosity measurement, TGA, DMA and SAXS, respectively. It was found that both IS and BL methods formed agglomerates of silica-rich phases and primary silica-rich phases in the hybrid films, but the former caused stronger interaction between silica and polymer than the latter, resulting in much bigger agglomerates and compacter structure. The ethoxy group at silica was favorable for enhancing the interaction between silica phase and polymer, even between silica phases as well. The interaction between silica phase and polymer caused increasing viscosity, modulus and Tg, while the interaction between silica phases themselves increased the extent of micro-phase separation, especially for the hybrid films prepared by IS method.     

Polypropylene wax (PPw)/silica hybrid by in situ non-aqueous sol–gel process for preparation of PP/silica nanocomposites

This paper presented a novel approach to prepare PP/silica nanocomposites. First, PPw-g-KH570 (γ-methacryloxypropyl trimethoxysilane) was obtained by pre-irradiation grafting method and characterized by FTIR and TGA. Then the non-aqueous sol–gel gelation kinetics of TEOS (tetraethoxysilane)-formic acid system in xylene was researched. Subsequently PPw/silica hybrid was obtained by in situ non-aqueous sol–gel reaction of TEOS in the presence of PPw-g-KH570 solution in xylene. Finally PP/silica nanocomposites were prepared by blending of PP matrix and PPw/silica hybrid. The mechanism of in situ formed PPw/silica hybrid was proposed. The morphology of PPw/silica hybrid and microstructures of PP/silica nanocomposites were characterized by TEM and SEM. The mechanical and thermal properties of PP/silica nanocomposites were also well studied by tensile tests and DSC. It was showed that the nanosilica particles were well dispersed in PPw/silica hybrid with the aid of grafting KH570 due to co-condensation by grafted KH570 and TEOS. PPw/silica hybrid was well dispersed in PP matrix with good compatibility and strong interactions. The resulted PP/silica nanocomposites possessed better performance than that of pure PP matrix.     

人神经母细胞瘤的磷酸化膜蛋白质组分析

针对人神经母细胞瘤SH-SY5Y细胞系的磷酸化膜蛋白质组,发展了基于多酶酶解法结合杂化硅胶基质固定化钛离子亲和色谱(Ti4+-IMAC)整体柱富集的分析策略。该方法通过对细胞裂解液进行超速离心,以及1 mol/L NaCl和0.1 mol/L Na2CO3顺序清洗,获得膜蛋白质组分。所提取的蛋白质分别经胰蛋白酶、胰凝乳蛋白酶和胃蛋白酶平行酶解,产生的肽段经Ti4+-IMAC整体柱选择性富集磷酸肽后,采用纳升级反相液相色谱分离和质谱鉴定,成功鉴定到43个磷酸化蛋白质,其中有14个定位于膜上。研究结果表明,采用该策略开展SH-SY5Y细胞系磷酸化膜蛋白质组学分析有望加速对该肿瘤的研究和相关潜在标记物的筛选。     

Composite Nafion membrane embedded with hybrid nanofillers for promoting direct methanol fuel cell performance

A special type of hybrid nano-particles was incorporated into the Nafion^® matrix to form a composite membrane. These nano-particles possessed a core–shell structure consisting of silica core (<10 nm) and a densely grafted oligomeric ionmer layer, which was synthesized via atom transfer radical polymerization (ATRP) on the particles’ surface. Besides considerable improvement in the proton conductivity of the membrane, the presence of these hybrid nano-particles in the Nafion^® matrix also repressed its methanol permeability by almost four times. The composite membrane also demonstrated superior performance when tested in a single cell membrane-electrolyte assembly (MEA) under direct methanol fuel cell (DMFC) operating condition. It was found that the composite membrane enabled a power density output that was 1.5 times greater than that of pristine Nafion^®.     

Morphology of a Poly(imide siloxane) Segmented Copolymer/Silica Hybrid Composite

The role of polydimethylsiloxane (PDMS) as a compatibilizer of polyimide/silica hybrid composites was investigated. Introduction of PDMS into a polyimide matrix retards the phase separation of hybrid composites and also prevents the formation of high‐molecular‐weight silicate. PDMS interacts with silica because of the similarity of its structure with the sol‐gel glass matrix of the silica precursor, indicating that poly(imide siloxane)/silica might be a good candidate material for organic/inorganic hybrid composites.     

线性聚胺介导的SiO2 杂化纳米粒子的仿生合成

我们报道了在环境条件下采用简单的线性聚胺作为仿生结构导向剂快速可控的合成了聚合物杂化的SiO2纳米粒子。采用TEM, EDX, FT IR, TGA等方法对所合成的纳米粒子的形态、结构和组成进行了详细表征。另外,我们也发现纳米粒子的形成强烈依赖于体系中SiO2的矿化反应时间。所合成的杂化纳米粒子预期将在催化和生物医学等领域具有重要的应用价