共查询到19条相似文献,搜索用时 171 毫秒
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以3-异氰酸丙基三乙氧基硅烷和对甲氧基苯胺为原料合成了一种可以自组装形成有机-无机杂化材料的化合物--3-(脲基-4-甲氧基苯基)丙基三乙氧基硅烷. 采用FT-IR, 1H NMR, DSC 和XRD 分析方法对该化合物的结构以及结晶性进行了表征. 将该化合物与聚乙烯醇(PVA)共混, 利用化合物的自组装性质构筑结构均一且致密无孔的离子通道杂化膜, 通过自制的膜运输实验装置测定膜对阳离子的传输性能并提出了相应的传输机制. SEM 照片显示, 自组装杂化膜致密无缺陷, 膜厚度为8 μm. 选择5 种阳离子进行运输实验测试, 结果表明, 自组装杂化离子通道膜对一价的碱金属离子Li+, Na+和K+有很好的传输功能, 这要归功于杂化材料中甲氧基苯基与碱金属阳离子形成的阳离子-π相互作用力. 碱金属阳离子在膜中的扩散过程可由溶解-扩散机制来解释, 结果显示, Li+, Na+和K+在杂化膜中传输的渗透率大小为: PNa+ > PK+ > PLi+ , 说明本研究中的的自组装杂化离子通道膜对Na+有优先选择性. 杂化离子通道膜对二价的Ca2+和Mg2+没有传输作用, 此结果给一二价阳离子的分离带来很好的研究思路. 相似文献
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利用浸泡和旋涂静电吸附自组装技术制备了含有偶氮生色团的聚电解质薄膜,比较了两种方法在自组装膜生长机理、膜结构以及膜光学性能方面的差异.利用紫外光谱和椭偏仪检测自组装膜的生长情况,利用原子力显微镜对膜表面结构进行了表征,并用偏振激光在膜表面进行了写光栅实验.结果表明,采用浸泡法和旋涂法都可以制备出表面光滑均匀的含偶氮生色团的聚电解质自组装膜.但是浸泡法自组装膜的生长速度要比旋涂法快.在自组装膜厚度较小的情况下,旋涂法得到的自组装膜可以写出明显的光栅而浸泡法不可以.随着自组装膜厚度的增加,两种方法得到的自组装膜都可以写出明显的光栅.这些结果说明浸泡法自组装膜内部聚电解质分子的层间穿插比较严重,而旋涂法自组装膜内分子穿插要弱得多. 相似文献
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沿S0I0路径,以十六胺为模板剂,以3-氨丙基三乙氧基硅烷为有机硅源,通过与TEOS共水解沉淀合成了氨丙基官能化HMS介孔分子筛.采用粉末X-射线衍射分析、N2吸/脱附、扫描电镜分析、高分辨透射电镜分析、傅立叶变换红外分析以及元素分析等表征手段,对所合成的材料进行表征.氨丙基官能化HMS介孔分子筛具有worm-like孔道结构,且较为均一的孔径分布.研究了前体硅源中3-氨丙基三乙氧基硅烷含量的变化对氨丙基官能化HMS介孔分子筛的相结构及织构性能的影响.傅立叶变换红外分析表明,NH2-CH2-CH2-CH2有机基团分布在杂化HMS介孔孔道中. 相似文献
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采用自组装技术在单晶硅表面制备了3-氨基丙基三乙氧基硅烷(APTES)-SiO2-APTES复合膜,并对其表面的组成、结构及摩擦性能进行了表征.结果表明:复合膜表面对水的接触角约为63°,且表面平整、致密,其平均粗糙度(Ra)约为0.963nm.通过原子力显微镜(AFM)和透射电子显微镜(TEM)观察到夹层中SiO2颗粒的粒径约为20-50nm,较均匀地分布在第一层APTES膜的表面.与APTES自组装单层膜(SAMs)相比,APTES-SiO2-APTES复合膜由于纳米SiO2颗粒的引入而表现出更低的摩擦系数和更长的耐磨寿命. 相似文献
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利用4,4’-二羟甲基-1,4-庚二炔功能单体作为扩链剂合成了一系列炔基接枝量不同的水性聚氨酯(WPU),然后基于铜催化的叠氮-炔基环加成(CuAAC)反应,采用3-叠氮基丙基三乙氧基硅烷(APTES-N3)改性炔基功能化WPU,制备了室温链间自交联有机-无机杂化WPU. 采用红外光谱(FTIR)和核磁氢谱(1H NMR)表征了自交联有机-无机杂化WPU. 探讨了APTES-N3接枝量对WPU膜性能和WPU乳液形态的影响. 结果表明,随着APTES-N3含量增加,WPU膜的结晶性逐渐下降;耐水性、耐溶剂性和热稳定性逐渐增强;WPU乳液粒子黏连程度增加. 当APTES-N3质量分数从0增大到12%时,WPU膜的拉伸强度从14.3 MPa增加到28.6 MPa. 相似文献
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采用苯并15冠5、没食子酸甲酯以及1-溴十一烯等物质为原料,合成超分子化合物2-(1-甲基羟甲基)-[1,4,7,10,13-苯并15冠5]-3,4,5-三[4-(10-十一烯-1-羰基)苄氧基]苯甲酸酯.然后用紫外光接枝法将其接枝到聚丙烯腈(PAN)微孔膜表面,构筑具有离子传输功能的离子传输复合膜,接枝量为3.025 mg/cm2.通过ATR,XPS,SEM以及AFM等手段对离子传输膜的结构性能进行表征.结果表明,这种超分子化合物在PAN膜的表面自组装成柱状通道,并形成致密皮层.采用自行设计的膜运输装置对膜的离子识别和运输功能进行评测.通过与非功能材料(丙烯酸)接枝膜的对比,可以认为本文制备的离子识别膜可以选择性识别和运输碱金属阳离子,其运输能力顺序为Na+>K+>Li+. 相似文献
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Sara Trujillo Clara E. Plazas Bonilla Marta S. Santos Joana M. Matos T. Gamboa Jairo E. Perilla João F. Mano José L. Gómez Ribelles 《Journal of Sol-Gel Science and Technology》2014,71(1):136-146
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. 相似文献
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《Journal of membrane science》2002,207(2):143-156
Coating a layer onto a support membrane can serve as a means of surface functionalization of membranes. Frequently, this procedure is a two-step process. In this paper, we describe a concept of membrane preparation in which a coating layer forms in situ onto a support membrane in one step by a co-extrusion process. Our aim is to apply a thin ion exchange layer (sulfonated polyethersulfone, SPES) onto a polysulfone support. The mechanical stability and adhesion of the ion-exchange material to the hydrophobic support membrane (polysulfone) has been studied by a systematic approach of initial proof-of-principle experiments, followed by single layer and double-layer flat sheet casting. Critical parameters quantified by the latter experiments are translated into the co-extrusion spinning process. The composite hollow fiber membrane has low flux as a supported liquid membrane for the copper removal due to the low ion exchange capacity of the SPES. The coating layer of the composite membrane is porous as indicated by gas pair selectivity close to unity. However, our new composite membrane has good nanofiltration properties: it passes mono and bivalent inorganic salts but rejects larger charged organic molecules. The experimental work demonstrates that co-extrusion can be a viable process to continuously prepare surface tailored hollow fiber membranes in a one-step process, even if the support and coating material differ significantly in hydrophilicity. 相似文献
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CaP/壳聚糖复合膜层的电化学共沉积研究 总被引:9,自引:0,他引:9
用电化学共沉积方法在医用钛合金表面成功制备了CaP/壳聚糖复合膜层,并用XRD,SEM,FTIR漫反射光谱和XPS等对复合膜层化学组成及结构进行表征.结果表明,加入壳聚糖可使钙磷沉积层结构发生显著变化,将壳聚糖掺入钙磷沉积层,形成CaP/壳聚糖复合物和杂化物.力学实验表明,在钛基底表面未进行表面预处理条件下,CaP/壳聚糖复合膜层与钛基底的结合力高达2.6MPa,比单一CaP电化学沉积层与基底的结合力提高约4倍.文中还对壳聚糖参与表面电沉积反应机理进行了讨论. 相似文献
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Chitosan-based porous organic-inorganic hybrid membranes supported by microfiltration nylon membranes were prepared, in which gamma-glycidoxypropyltrimethoxysilane (GPTMS) was used as an inorganic source as well as crosslinking reagent. Polyethylene glycol (PEG) with different molecular weight and content was used as imprinting molecule for morphology control. In situ crosslinking of chitosan and simultaneous polymerization of GPTMS in PEG template environment endowed the hybrid membrane with specific characteristics. Distinct hybrid effect between chitosan (CS) and GPTMS was revealed by shifting in X-ray diffraction (XRD) pattern, decomposition in simultaneous thermogravimetry and differential scanning calorimetry (TG/DSC) testing. As manifested by scanning electron microscopy (SEM), the molecular weight and content of PEG had remarkable effect on the resulting surface morphology of the hybrid membrane and a given surface morphology could be obtained by extracting of the imprinted PEG molecular. Among three types of porogen used: PEG 400, PEG 4000 and PEG 20000, only PEG 20000 could result in a porous surface. Moreover, a special porous surface with three-dimensional (3D) hierarchical structure-in-structure pore fashion was obtained when content of PEG 20000 was controlled at 15%. Experimental results also showed that the hybrid membrane had low swelling ratio and high stability in acidic solution. After conveniently coordinated with copper ions, the porous metal chelating hybrid membrane could effectively adsorb the model protein, bovine serum albumin (BSA). As expected, the hybrid membrane imprinted with 15% PEG 20000 had remarkably high copper ion binding and BSA adsorption capacity, which might result from the large surface area, high ligand density and suitable interconnected 3D hierarchical porous surface. 相似文献
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《Journal of polymer science. Part A, Polymer chemistry》2018,56(6):618-625
The selective transport of ions has crucial importance in biological systems as well as modern‐day energy devices, such as batteries and fuel cells, and water purification membranes. Control over ion movement can be exerted by ligation, ion channel dimensions, solvation, and electrostatic interactions. Polyelectrolyte hydrogels can provide aligned pathways for counter ion transport but lack mechanical integrity, while polyelectrolyte membranes typically suffer from the absence of an ion transport channel network. To develop polymer membranes for improved ion transport, we present the design of a novel material that combines the advantages of aligned pathways found in polyelectrolyte hydrogel and mechanical robustness in conventional membranes. The ionic species were organized via controlled copolymerization of a quaternizable monomer. Additionally, dimensional stability was then incorporated through a cast/crosslinking method to lock in the network of connected cationic groups. This strategy resulted in dramatically enhanced ion transport, as characterized by ionic conductivities (>80 mS/cm for Cl–, and ∼200 mS/cm for OH–). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 618–625 相似文献
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纳滤膜对电解质溶液分离特性的理论研究(II): 混合电解质溶液 总被引:3,自引:0,他引:3
假定纳滤膜具有狭缝状孔, 使用纯水透过系数、膜孔径及膜表面电势来表征纳滤膜的分离特征, 用流体力学半径和无限稀释扩散系数表征了离子特性. 采用扩展Nernst-Planck方程、Donnan平衡模型和Poisson-Boltzmann理论描述了混合电解质溶液中离子在膜孔内的传递现象, 计算了三种商用纳滤膜(ESNA1-LF, ESNA1和LES90)对同阴离子、同阳离子和含四种离子的混合电解质体系中离子的截留率, 并与实验数据进行了比较. 计算结果表明, 电解质溶液中离子在纳滤膜孔内传递的主要机理是离子的扩散和电迁移, 纳滤膜对混合电解质溶液中离子的分离效果主要由空间位阻和静电效应决定. 该模型在低浓度时对含一价离子的混合电解质溶液通过纳滤膜的截留率计算结果比较准确, 但对高浓度或含高价离子的混合电解质溶液则偏差较大. 相似文献
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Nagarale RK Shahi VK Schubert R Rangarajan R Mehnert R 《Journal of colloid and interface science》2004,270(2):446-454
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. 相似文献