硫化氢在ACF上吸附转化对ACF纳米孔空间结构的影响

Ｐ Ａ Ｎ Ａ Ｃ Ｆ, Ｈ２ Ｓ的吸附转化过程涉及到 Ａ Ｃ Ｆ 一个纳米孔体系改性的过程。在这个过程中, Ａ Ｃ Ｆ的孔结构和微表面结构发生很大变化,而这种变化在３５０℃以下是不可逆的。孔结构的变化主要表现为极微孔孔容的下降; Ｈ２ Ｓ的吸附转化产物较为稳定地吸存在微孔表面,微孔体系中原有的表面基团也发生较大变化。总之, Ｈ２ Ｓ在 Ａ Ｃ Ｆ上吸附转化的结果是形成一个与常规 Ａ Ｃ Ｆ性质不同的纳米孔空间。     

文摘

炭的微孔结构由缺陷碳层平面的紊乱网格组成,微孔就是层平面之间的空间。气体在微孔中的吸附具有以下性质:(1)由于相对孔壁间力场重迭而在低压下产生强吸附;(2)微孔网格收缩产生扩散效应;(3)分子尺寸和形状的选择性(分子筛分)。随着活化增强,活性炭表面分级度从3减小到2,这表明活化使孔表面光滑。计算表明狭缝型微孔的吸附势提     

以纳米SO_2粒子为模板由不同炭前躯体制备中孔炭(英文)

以纳米SO2粒子为模板,酚醛树脂、中间相沥青和聚丙烯腈为炭前躯体制备中孔炭。利用氮气吸附、元素分析和X-射线光电子能谱等分析了不同种类炭前躯体对中孔炭的影响。结果表明:在炭化温度和纳米粒子添加量相同的情况下,不同炭前躯体所制中孔炭的孔结构和表面化学性质不同。中间相沥青基中孔炭中微孔和中孔含量最少,酚醛基中孔炭中含有丰富的微孔和中孔,聚丙烯腈基中孔炭中含有大量的含氮官能团。     

CO2捕集用具有多级孔结构纳米孔炭的制备（英文）

以模板法结合化学活化法制备了具有分级结构的纳米孔炭。分别利用氮气吸附法和热重分析法考查KOH活化程度对模板法制备中孔炭的孔结构的影响和不同孔结构的多孔炭对CO2的吸附性能。结果表明,KOH活化不仅增加了大量的微孔,而且使得模板脱除得到的中孔数量降低。中孔吸附CO2对孔表面的利用率最高,而中孔和微孔的合适配比更有利用综合提高CO2的吸附量。制备的纳米孔炭具有较高的CO2吸附量和较好的循环性能和稳定性。     

纳米孔"炭"和纳米孔"碳"——对碳质多孔材料的几点思考

对碳质纳米孔隙材料提出一种新的分类方法——基于孔壁结构分类。根据这种方法，碳质多孔材料分为：纳米孔“碳”（石墨烯纳米孔材料）和纳米孔“炭”（类石墨微晶纳米孔材料）。具有相近比表面积的两种碳质材料由于具有不同的孔壁结构而可能具有完全不同的物理化学性质（比如：电化学性质）。文中简要介绍了两种新型的纳米孔“碳”——单壁微孔“碳”和碳纳米管-DNA杂化物以及区分纳米孔“碳”和纳米孔“炭”的重要判据：拉曼光谱。     

以MgO为模板剂制备纳米中孔炭及其应用研究进展

无需任何稳定和活化过程,采用MgO为模板剂,选择不同的碳前驱体可制备高比表面积且含有大量中孔的活性炭.综述了具体制备方法、制备条件对孔结构的影响、纳米孔结构形成机理、该方法的优点以及该法所得纳米中孔活性炭的应用前景.通过选择不同的MgO前驱体可调节活性炭中孔大小;而中孔和微孔的相对体积则由碳前驱体控制.采用该法制备的中孔炭作为电容器、吸附材料等在能源、资源和环境方面的应用前景相当广阔.     

新型中空炭纳米球在水系中性电解液中的超电容特性

采用具有微孔壳层的新型单分散中空炭纳米球作为电极材料,利用循环伏安、恒流充放电和交流阻抗等电化学测试方法,研究了中空炭纳米球在K2SO4、Li2SO4和Na2SO4等水系中性电解液中的超电容特性。结果表明,由于具有独特的微孔壳-球状中空腔纳米结构,该中空炭纳米球电极材料在这3种中性电解液中均表现出优异的倍率性能和高效的电化学活性表面,是一种有潜力的超级电容器用炭电极材料。     

结构有序、双重孔隙中孔炭材料的合成与表征

采用纳米涂层技术,以介孔分子筛SBA 15为模板,在其纳米孔道内引入糠醇/草酸溶液,经原位聚合,炭化后制得炭/SBA 15复合物。采用化学法脱除模板后制得具有规则结构的中孔炭。高分辨TEM表征结果显示该中孔炭是由纳米炭管相互联接、堆积而成,且具有六方对称结构。氮吸附结果显示其比表面积高达2000m2/g,孔径呈双峰分布。孔径相对较大的孔隙来源于SBA 15孔道经纳米涂层后所保留的孔隙;孔径相对较小的孔隙来源于SiO2移除后遗留的纳米孔空间。该方法可应用于以其他多孔氧化硅为模板制备新型纳米复合物的研究过程。     

木材制备生物炭的孔结构分析

选取9种木材,采用干蒸裂解工艺制备生物炭材料,采用压汞法测定生物炭的孔体积、比表面积和孔径分布,并且对它们的孔隙结构进行对比研究。结果表明:由果木制备的生物炭的孔隙率最大,数值为53.13%,而桃木生物炭的孔隙率最小,数值为44.38%;通过分析生物炭材料在一定孔半径区间内的孔体积分布曲线和孔表面积分布曲线,得出了9种生物炭中小孔和微孔数量较多的为槐木和杏木,大孔和中孔数量较多的为桃木和桐木;聚类分析9种生物炭孔结构相似度发现,果木、柳木、槐木和杏木为微孔类,枸木和椿木为小孔类,柿木和桃木为中孔类,桐木为大孔类。     

低介电常数聚酰亚胺薄膜的制备与性能研究

用单体4,4′-二胺基二苯醚（ODA）和均苯四甲酸二酐（PMDA）添加纳米SiO2,在溶剂N,N-二甲基乙酰胺（DMAC）中,采用原位聚合法合成SiO2/聚酰亚胺（PI）复合薄膜。用氢氟酸刻蚀SiO2纳米粒子,引入纳米微孔,形成含有微孔的PI薄膜。造孔剂含量为15%时,薄膜的介电常数从纯聚酰亚胺的3.54降低至3.05（1kHz）。用透射电镜表征微孔结构,分析了微孔孔径和造孔剂（SiO2）含量对薄膜介电常数、耐热性、疏水性和机械强度等性质的影响。     

Molecular recognition of alcohol by volume phase transition of cross-linked poly(2-methacryloyloxyethyl phosphorylcholine) gel

The swelling behavior of a cross-linked poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) gel in various water/alcohol mixtures was investigated. When the poly(MPC) gel was immersed in various water/alcohol mixtures, a change in the gel volume was observed depending not only on the composition of the alcohol in the mixture but also on the chemical structure of the alcohol. In water/monohydric alcohol mixtures, the poly(MPC) gel had an irregular swelling behavior with a change in the composition of the alcohol, showing the so-called reentrant volume phase transition. These volume phase transition strongly depended on a hydrophobic group, i.e. the polarity of the alcohol. On the other hand, polyhydric alcohol (diol or triol) did not affect the swelling of the poly(MPC) gel even when the composition of the alcohol was changed.

These results suggest that water molecules hydrated on the poly(MPC) chains were withdrawn by hydration of the alcohol molecules and the volume of the poly(MPC) gel decreased. That is in good agreement with the hydration ability of the alcohol and its polarity. Thus, the poly(MPC) gel could recognize a difference in the polarity among the alcohol molecules.     

Effects of photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on physical properties of cross-linked polyethylene in artificial hip joints

Osteolysis caused by wear particles from polyethylene in the artificial hip joints is a serious issue. We have used photo-induced radical graft polymerization to graft 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer onto the surface of cross-linked polyethylene (CLPE-g-MPC) in order to reduce friction and wear at the bearing surface of the joint. The physical and mechanical properties of CLPE and CLPE-g-MPC were not significantly different, expect that the friction coefficient of untreated CLPE cups was 0.0075, compared with 0.0009 for CLPE-g-MPC cup, an 88% reduction. After 3.0 × 10⁶ cycles in the hip joint simulator test, we could not observe any wear of CLPE-g-MPC cups. We concluded that the advantage of photo-induced radical graft polymerization technique was that the grafted MPC polymer gave a high lubricity only on the surface and has no effect on the bulk properties of the CLPE substrate.     

On the fluorescence of pyrrole derivative oligomer

In this work we have investigated the ground state and others eletronic properties of the biosensor 3-methyl pyrrole-4-carboxilic acid (MPC) oligomers and related compounds. We considered the systems described by a DFT/B3LYP/6-31G* type Hamiltonian and explored the effects due to the presence of conformational defects. Furthermore the excited states have been determined by a post Hartree–Fock CI methodology.The results revealed the existence of different electronic patterns for the MPC if compared to the ones existing for the oligopyrrole derivative systems. The response of one of investigated polymers (MPC) was found to be critically dependent on the radicals linked to the studied oligomer chain structure so that the electronic structure analyses should be easily improved by choosing a proper set of preparation parameters to design conducting polymers with desirable properties.     

Continuous free-flow electrophoresis of water-soluble monolayer-protected clusters

There has recently been a surge of interest in the properties and applications of monolayer protected clusters (MPCs). MPCs are metal nanoparticles that have unique optical, chemical, and electrochemical properties resulting from their small size. Because the size defines their properties, MPC particle size fractionation is important for control of the MPC characteristics for use in many potential applications. This paper explores the use of continuous free-flow electrophoresis (CFE) for the size fractionation of N-(2-mercaptopropionyl)glycine (tiopronin) monolayer protected gold clusters into monodisperse nanoparticle samples. CFE is a fractionation technique that isolates monodisperse particle sizes into several different collection vials on the tens of milligrams scale. This allows the MPCs to be separated based on their electrophoretic mobilities into isolated, monodisperse particles across a wide range of sizes. CFE separation of water-soluble tiopronin MPCs yielded fractions that varied in color, UV-visible spectra, transmission electron microscopy (TEM) size histograms, and solubility, indicating narrow size dispersity in the isolated fractions. UV-visible spectrophotometry verified the separation of the tiopronin MPCs through the inspection of surface plasmon resonance peak sizes for the different fractions. TEM was also used to verify the narrowed dispersity of MPC samples. The ability to separate water-soluble nanoparticles into 30 or more fractions in a continuous flow process will enable future studies on their size dependent properties.     

MgO晶须增强磷酸镁水泥力学性能的研究

MgO 晶须弹性模量高,长径比大,掺加到磷酸镁水泥(MPC)中可以产生增强增韧作用。研究了水料比、缓凝剂掺量不同时 MgO 晶须对 MPC 力学性能的影响,采用 SEM 和重量法研究了 MgO 晶须在 MPC 中的分布及水化,分析了 MgO 晶须增强 MPC 的机理。结果表明,掺加3%~5%的 MgO 晶须使 MPC 在水料比和缓凝剂掺量较高时获得良好的早期强度;MgO 晶须在 MPC 中搭接形成网络结构,并通过晶须桥联、裂缝偏转等作用,使 MPC 的早期力学性能显著增强;MgO 晶须参与水化,提高了晶须与 MPC 基体的握裹力和相容性;随着龄期延长,晶须水化程度加深,使 MPC 基体更加致密,后期抗压强度增长明显,但晶须的桥联作用逐渐减弱,MPC 的后期抗折强度增长幅度较小。     

The preparation of heparin-like hyperbranched polyimides and their antithrombogenic,antibacterial applications

1,3,5-Tris(4-aminophenoxy) benzene (TAPOB) and 2,2-bis [4-(3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA) were used to synthesize an amino-terminated hyperbranched polyimide (AM-HBPI). Then, the 2-methacryloyloxyethyl phosphorylcholine-modified hyperbranched polyimide (HBPI-MPC) was obtained through the graft modification of MPC onto AM-HBPI by Michael addition. The infrared spectroscopy and X-ray photoelectron spectroscopy spectra showed MPC molecules were successfully grafted onto the HBPI molecules. The HBPI-MPC films exhibited slightly decreased thermal stabilities with 5% weight loss temperature in the range of of 418–483?°C in nitrogen, compared with the pure HBPI film. With the increase of MPC grafting amount, the static water contact angles decreased from average 84.0° of the pure HBPI film to average 45.0° of the HBPI-MPC film with 20% MPC. Meanwhile, the increased surface roughness of the HBPI-MPC films increased the contact areas with the platelets, enhancing their anticoagulant efficiency. The number of platelet adhesion declined and the shape of platelet changed from flat to round. The recalcification times grew from average 300?s of pure HBPI to average 551?s of the HBPI-MPC film with 20% MPC, indicating improved anticoagulant properties and biocompatibility. Bacterial adhesion test also demonstrated the number of bacterial adhesion was significantly reduced and antibacterial properties were improved. Thus, the HBPI-MPC films have great application prospects as biomedical anticoagulant materials.

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Change in cell adhesion property on cytocompatible interface using phospholipid polymer grafted with poly( , -lactic acid) segment for tissue engineering

Tissue engineering is a multi-disciplinary science that utilizes basic principles from materials engineering and molecular biology to reconstruct tissues from polymer matrices and cellular components. Artificial skins were well known as one of the concrete examples. Technological innovation of the tissue engineering must be contributed to improve quality of life. From the viewpoint, design of cytocompatible materials for tissue engineering would be the most important candidate to reconstruct tissue. 2-Methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate, and polylactic acid (PLA) macromonomer were polymerized for the preparation of cytocompatible interface. The polymer may involve following novel properties: (i) cytocompatibility by phospholipid groups, and (ii) enhancement of cell adhesion by PLA segment. The results of X-ray photoelectron spectroscopy showed the MPC unit and PLA segment on the membrane, which was prepared by dip coating. The surface mobility by contacting water was estimated with static contact angle measurement. The contact angle by water decreased after contact with water due to the chain rearrangement of hydrophilic MPC unit. Fibroblast cells adhesion and protein adsorption on the membranes were studied. The number of cell adhesion and cell proliferation on the membrane was well correlated with each other. Furthermore, the number of cell adhesion was proportional to the PLA macromonomer (MaPLA) composition. The adherent cell morphology showed round shape, because of the existence of MPC unit. However, the cell morphology would be spread after the cell proliferation. These findings suggest that the change in the polymer composition by combination of MPC and MaPLA could regulate the number of cell adhesion and the morphology.     

Change in cell adhesion property on cytocompatible interface using phospholipid polymer grafted with poly(D,L-lactic acid)segment for tissue engineering

Tissue engineering is a multi-disciplinary science that utilizes basic principles from materials engineering and molecular biology to reconstruct tissues from polymer matrices and cellular components. Artificial skins were well known as one of the concrete examples. Technological innovation of the tissue engineering must be contributed to improve quality of life. From the viewpoint, design of cytocompatible materials for tissue engineering would be the most important candidate to reconstruct tissue. 2-Methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate, and polylactic acid (PLA) macromonomer were polymerized for the preparation of cytocompatible interface. The polymer may involve following novel properties: (i) cytocompatibility by phospholipid groups, and (ii) enhancement of cell adhesion by PLA segment. The results of X-ray photoelectron spectroscopy showed the MPC unit and PLA segment on the membrane, which was prepared by dip coating. The surface mobility by contacting water was estimated with static contact angle measurement. The contact angle by water decreased after contact with water due to the chain rearrangement of hydrophilic MPC unit. Fibroblast cells adhesion and protein adsorption on the membranes were studied. The number of cell adhesion and cell proliferation on the membrane was well correlated with each other. Furthermore, the number of cell adhesion was proportional to the PLA macromonomer (MaPLA) composition. The adherent cell morphology showed round shape, because of the existence of MPC unit. However, the cell morphology would be spread after the cell proliferation. These findings suggest that the change in the polymer composition by combination of MPC and MaPLA could regulate the number of cell adhesion and the morphology.     

磷酰胆碱共聚物的合成及膜的生物相容性

为了研究磷酰胆碱类聚合物的生物相容性,以偶氮二异丁腈(AIBN)为引发剂,采用自由基聚合制备了系列2-甲基丙烯酰氧乙基磷酰胆碱(MPC)与甲基丙烯酸丁酯(BMA)、甲基丙烯酸异辛酯(EHMA)的共聚物PMB、PMEH.用红外光谱、元素分析、核磁共振等方法对其结构进行了表征并探讨了其在不同溶剂中的溶解性,为该类物质的提纯提供依据;通过溶剂挥发法制备了共聚物薄膜,血小板黏附实验显示,含有MPC的聚合物薄膜比不含MPC的聚合物薄膜有更好的血液相容性;溶胀度测试显示MPC聚合物薄膜有非常好的吸收水的能力,且平衡含水量(EWC)会随着MPC在聚合物薄膜中含量的增加而增加,当MPC在PMB20中的摩尔含量为18%时,平衡含水量可以达到47%,这是磷酰胆碱类聚合物薄膜具有优良生物相容性的原因之一.     

Supporting electrolyte and solvent effects on single-electron double layer capacitance charging of hexanethiolate-coated Au140 nanoparticles

Sequential injections of single electrons (or holes) into the cores of Au(140) hexanethiolate monolayer-protected clusters (MPCs) occur at measurably different electrochemical potentials owing to the extremely small (subattofarad) values of the single MPC capacitance (C(MPC)) of the nanoparticle. The potential increment for each sequential injection is DeltaV = e/C(MPC). The dependence of DeltaV on the concentration of supporting electrolyte (from 1 to 100 mM), measured using square wave voltammetry, is shown to be caused, primarily, by changes in the diffuse double layer component (C(DIFFUSE)) of C(MPC). The dependence of C(DIFFUSE) on r(core), the radius of the nanoparticle, is considered. Additionally, significant changes in the magnitude of the compact double layer component (C(COMPACT), equivalent to the Stern layer) of C(MPC) were induced by adding hydrophobic solvent components such as hexane or dodecane or by introducing hydrophobic electrolyte ions (tetrabutyl-, tetrahexyl-, and tetraoctylammonium, perchlorate, and tetraphenylborate). These changes are interpreted as specific solvation and ion penetration of the hexanethiolate monolayer. For brevity we will refer to these phenomena as solvation/penetration phenomena.