反胶团或微乳液法制备超细颗粒的研究进展

本文对超细颗粒的各种化学制备方法进行了综合评述，并重点介绍了一种新的超细颗粒制备法──反胶团或微乳法。从以下几个方面对反胶团或微乳法制备超细颗粒的研究工作进行了归纳和总结：各种用于制备超细颗粒的反胶团或微乳体系，已经制得的超细颗粒种类，反胶团或微乳中颗粒的形成机理，以及反胶团或微乳法制备超细颗粒的影响因素等。     

用反向胶团制备稳定ZrO2超细粉的研究

以注入法研究了金属离子及氨水在ＡＯＴ－ｉｓｏｏｃｔａｎｅ－ｗａｎｔｅｒ反胶团中的溶解性，用光散射技术测定了胶团的大小，用冷冻蚀刻复形技术表征了反胶团的微观结构；研究了以反胶团为基础溶液多种制备方式对粉末的影响，实验制备了Ｙ２Ｏ３及ＣｅＯ２稳定的四方相ＺｒＯ２超细粉，研究表明，将金属离子包溶于反胶团是制备良好颗粒的必要条件。     

表面活性剂有序聚集体在纳米材料制备中的应用

介绍了表面活性剂在溶液中形成的各种有序聚集体－胶团（反胶团），微乳液，液晶及囊泡等，综述了它们作为微反应器或作为模板在纳米材料制备中的应用。     

反胶团萃取嗜热芽孢杆菌HS08发酵液中胞外蛋白酶研究

讨论了影响AOT/异辛烷反胶团体系萃取嗜热芽孢杆菌HS08发酵液中耐高温中性蛋白酶的因素.实验结果表明,AOT/异辛烷反胶团在很短的时间内能达到萃取平衡,100 mmol.L-1NaCl的离子强度有助于蛋白酶的反胶团萃取.在50 mmol.L-1AOT、pH4.5、100 mmol.L-1NaCl、油水相体积比为1的条件下萃取5 min能达到80%以上的酶活力回收率.     

反胶团微乳液法制备超微细颗粒的研究进展

简要阐述了用反胶团微乳法制备超微细颗粒的基本理论，介绍了在使用该法制备超微细颗粒中的几种具体模式，并讨论了相关的影响因素。     

表面活性剂在纳米材料形貌调控中的作用及机理研究进展

介绍了表面活性剂在纳米材料合成中的软模板作用和稳定分散作用,重点综述了利用表面活性剂在溶液中聚集形成的胶团、反胶团、微乳液、囊泡、液晶等各种有序聚集体辅助制备纳米材料的作用机理.展望了表面活性剂在纳米材料形貌调控中的应用前景.     

应用反胶团体系制备纳米粒子的形态控制

与其他制备方法相比,反胶团体系在制备纳米粒子方面具有明显的优势,这一点在对产物粒子形态的控制方面体现得最显著.表面活性剂在体系中起模板作用,因而可以通过控制表面活性剂形成的胶束的形态来控制产物粒子的形态.着重介绍在用反胶团体系制备纳米粒子的方法中,对产物粒子形态控制方面的研究进展.另外,孤立的纳米粒子与其聚集体的性质并不相同,聚集体的性质受聚集产物自身组装形态的控制,因此还概括了近年来在反胶团体系中制备纳米粒子聚集体的研究工作.     

用扩散理论解释激光选择性催化的原理(英文)

激光选择性催化(LISA)技术可用于高分子的选择性电镀,本文主要研究了Pd/Sn催化系统在这个过程中的原理.实验表明在催化后的清洗步骤对电镀的选择性有很大影响,由于激光处理后在高分子表面产生了多孔结构,相对于在未被激光处理的表面上,Pd/Sn催化胶团需要更长的时间才能被清洗掉.本文中,采用扩散理论描述催化和清洗后在样品表面催化胶团的浓度分布,其中催化胶团在多孔介质中的扩散系数是研究的难点.采用NanosightR颗粒检测仪器测量胶粒的尺寸,用AliconaInfiniteFocus显微镜对激光处理后的表面多孔结构进行了测量和表征.最后测得催化胶团的浓度百分比曲线,可用于表征催化和清洗时间对浓度的影响.     

茶叶发酵中的酶学研究进展

茶叶经过发酵后,酚氨比降低,芳香类物质增加,农药残留降解且溶入许多微生物代谢活性物质以及微生物菌体,茶叶品质得以改善.所以,发酵对提高茶叶综合利用具有积极意义.文中就茶叶发酵过程中的多酚氧化酶、过氧化物酶、脂肪氧化酶、纤维素酶、果胶酶等酶的作用机制、研究方法等方面进行了概述,并展望了酶在茶叶发酵工艺中的发展前景.     

高浓度水相Sb2O5胶体直接制备环己酮Sb2O5胶体

以体积质量浓度为60％的高浓度水相Sb2O5胶体为原料制备环己酮Sb2O5肢体。直接向该水相Sb2O5胶体中加入数种表面活性剂和环已酮，经过胶团在水中聚沉、胶团表面改性、胶团重新分散于环己酮等几个步骤生成环己酮Sb2O5胶体，原水相Sb2O5胶体中的水随之一起成胶。经试验，该胶体可以与聚氨酯以任意比例互相融合。     

Graphite-Poly(tetrafluoroethylene) Composite Enzyme Electrodes as Suitable Biosensors in Predominantly Nonaqueous Media

The performance of a graphite-poly(tetrafluoroethylene) Teflon composite amperometric ferrocyanide-mediated peroxidase electrode in a predominantly nonaqueous medium such as reversed micelles is discussed and compared with the behavior in a medium formed by acetonitrile/water. The composite electrode was constructed by purely physical entrapment of both the enzyme and the mediator into the bulk of the graphite-Teflon matrix with no need of covalent attachments. This biosensor responded rapidly to the changes in the concentration of both hydrogen peroxide and 2-butanone peroxide in reversed micelles formed with ethyl acetate, 0.1 mol L(-)(1) dioctyl sulfosuccinate as the surfactant, and a 4% phosphate buffer (pH 7.4) as the dispersed phase. The electrode showed a long-term operation due to the renewability of its surface. Moreover, reproducible responses were obtained with different electrodes fabricated from different composite matrixes. No significant loss of the enzyme activity was observed after four months of dry storage at 4 °C of the composite electrode. Limits of detection of 2.1 × 10(-)(7) and 3.5 × 10(-)(7) mol L(-)(1) were obtained for H(2)O(2) and 2-butanone peroxide, respectively. The possibility of using this biocomposite electrode in flowing systems, using the reversed micelles as the carrier, has been demonstrated. The kinetic of the enzymatic reaction was faster in a 90:10 acetonitrile/phosphate buffer medium than in reversed micelles, which can be attributed to the higher water content present in the former medium. A similar stability of the biosensor and a slightly better sensitivity for peroxides was observed in the acetonitrile/water mixture when compared with reversed micelles. Finally, the electrode also performed well in the flow injection mode.     

一种全亲水两嵌段共聚物的多重胶束化

以1-氯代乙苯为引发剂,氯化亚铜/N,N,N′,N″,N″-五甲基二乙撑三胺(PMDETA)为催化体系,通过连续原子转移自由基聚合(ATRP)合成了聚丙烯酸叔丁酯-b-聚(甲基丙烯酸二甲胺基乙酯)(PtBA-b-PDMAEMA),然后用三氟乙酸将其水解,得到一种全亲水的嵌段共聚物聚丙烯酸-b-聚(甲基丙烯酸二甲胺基乙酯)(PAA-b-PDMAEMA)。将其溶于水中,只需要调节水的pH值就可以调节聚合物自组装完成从正向胶束到反向胶束的转变。在pH为2.4时,嵌段共聚物自组装形成以PDMAEMA为核,PAA为壳的核壳结构胶束(Dh=253.4 nm);当pH升高到10.0时,共聚物自组装形成核壳结构相反的反向胶束(Dh=279.9 nm)。进一步用动态光散射和透射电镜对胶束的温度敏感性进行了初步研究。     

Synthesis of Ni nanoparticles by reduction of NiCl2 ionic clusters in the confined space of AOT reversed micelles

Stable Nickel nanoparticles have been synthesized by a novel synthetic route based on the reduction of NiCl₂ ionic clusters in the confined space of reversed micelles. The reaction was carried out by adding anhydrous NaBH₄/ethanol solution to a solution of NiCl₂ ionic clusters nanoencapsulated in bis(2-ethylhexyl)sulfosuccinate (AOT) reversed micelles in the presence of n-dodecylmercaptane as capping agent. As highlighted by FT-IR, an extraction with water eliminates surfactant and side products leaving lipophilic Nickel nanoparticles to be dispersed in the organic solvent. UV-Vis investigation ascertained the formation of stable metal Nickel nanoparticles exhibiting novel optical properties.     

Graphite-teflon composite bienzyme electrodes for the determination of cholesterol in reversed micelles. Application to food samples

A bienzyme amperometric composite biosensor for the determination of free and total cholesterol in food samples is reported. Cholesterol oxidase and horseradish peroxidase, together with potassium ferrocyanide as a mediator, are incorporated into a graphite-70% Teflon matrix. The compatibility of this biosensor design with predominantly nonaqueous media allows the use of reversed micelles as working medium. The reversed micelles are formed with ethyl acetate as continuous phase (in which cholesterol is soluble), a 4% final concentration of 0.05 mol L(-1) phosphate buffer solution, pH 7.4, as dispersed phase, and 0.1 mol L(-1) AOT as emulsifying agent. Studies on the repeatability of the amperometric response obtained at +0.10 V, with and without regeneration of the electrode surface by polishing, on the useful lifetime of one single biosensor and on the reproducibility in the fabrication of different pellets illustrate the robustness of the biosensor design. Determination of free and total cholesterol in food samples such as butter, lard, and egg yoke was carried out, and the obtained results were advantageously compared with those provided by using a commercial Boehringer test kit.     

琥珀酸二异辛酯磺酸钠的合成与新应用

针对琥珀酸二异辛酯磺酸钠的工业生产技术,从提高琥珀酸二异辛酯磺酸钠产品的纯度出发,概括和总结了琥珀酸二异辛酯磺酸钠的酯化和磺化合成技术,及合成工艺中催化剂、温度、助剂和体系真空度等主要影响因素,简要介绍了该表面活性剂在反胶束制备纳米材料等方面的应用新进展,指出了目前琥珀酸二异辛酯磺酸钠生产工艺中存在的不足,展望了琥珀酸二异辛酯磺酸钠系列表面活性剂的发展方向和应用前景.     

Chemical reactivity in organized media: statistical entropy and information in crystals and enzymes

The control of chemical reactivity has been a subject of intense research activity for many years. It is known that supramolecular systems are capable of influencing the outcome of chemical reactions to levels not easily achieved by homogeneous liquids. Their influence is not always expressed through specific interactions that stabilize a transition state. Their role can be frequently ascribed to the structural pre-organization of the reactant towards particular chemical reactions. Because of this, systems as diverse as micelles, zeolites, enzymes and crystals are frequently referred to as organized media. Recent work on reactions in organized media may be analyzed with an intuitive model based on simple statistical entropy principles.     

Electrochemical performance of steel in cement extract and bulk matrix properties of cement paste in the presence of Pluronic 123 micelles

The influence of Pluronic P123 (PEO₂₀-PPO₇₀-PEO₂₀) non-stabilized micelles (of 10 nm size) on the corrosion behavior of low-carbon steel in cement extract was studied, using electrochemical impedance spectroscopy (EIS) and potentio-dynamic polarization (PDP). Mercury intrusion porosimetry (MIP) was employed to derive the impact of admixed P123 micelles on porosity and pore-size distribution of cement paste. As far as steel corrosion resistance is concerned, a positive effect was observed, initially denoted to the presence of the polymer itself, rather than the presence of micelles. Further, the P123 micelles were found to result in increased corrosion resistance in the presence of 1 % and 3.5 % NaCl in the alkaline environment of cement extract. There was no significant influence on porosity and pore size distribution of the admixed in cement paste P123 micelles. The observed phenomena are related to self-assembly of the micelles only within higher ionic strength and the presence of chloride, in which case the critical micelle concentration is reduced. At micelles concentration of 0.024 g/l for the chloride-free cement extract (and the solid cement paste specimens, respectively), the medium actually contain unimers that have minimal impact on electrochemical performance and/or microstructural properties. In contrast, with increased ionic strength of the medium (1?3.5 % NaCl and altered ion concentrations resulting from the anodic/cathodic reactions within steel corrosion), the positive effect of 0.024 g/l micelles (and higher of 0.072 g/l) is more pronounced, i.e., increased corrosion resistance and anodic control with external polarization was observed.     

Engineering a Hollow Carbon Sphere-Based Triphase Microenvironment for Enhanced Enzymatic Reaction Kinetics and Bioassay Performance

Electrochemical bioassays based on oxidase reactions are frequently used in biological sciences and medical industries. However, the enzymatic reaction kinetics are severely restricted by the poor solubility and slow diffusion rate of oxygen in conventional solid‒liquid diphase reaction systems, which inevitably compromises the detection accuracy, linearity, and reliability of the oxidase-based bioassay. Herein, an effective solid‒liquid‒air triphase bioassay system is provided that uses hydrophobic hollow carbon spheres (HCSs) as oxygen nanocarriers. The oxygen stored in the cavity of HCS can rapidly diffuse to the oxidase active sites through the mesoporous carbon shell, providing sufficient oxygen for oxidase-based enzymatic reactions. As a result, the triphase system can significantly improve the enzymatic reaction kinetics and obtain a 20-fold higher linear detection range than the normal diphase system. Other biomolecules can also be determined using this triphase technique, and the triphase design strategy offers a new route to address the gas deficiency problem in catalytic reactions that involve gas consumption.     

Statistical modelling of biochemical pathways

The usefulness of Bayesian statistical methods for the modelling of biochemical reactions is examined. With simulated data, it is shown that these methods can effectively fit mechanistic models of sequences of enzymatic reactions to experimental data. These methods have the advantages of being relatively easy to use and producing probability distributions for the model parameters rather than point estimates, allowing more informative inferences to be drawn. Three Markov Chain Monte Carlo algorithms are used to fit models to data from a sequence of four enzymatic reactions. The algorithms are evaluated with respect to the goodness-of-fit of the fitted models and the time to completion. It is shown that the algorithms produce essentially the same parameter distributions, but the time to completion varies.