核/壳结构磁性Fe3O4@SiO2纳米粒子的制备及表征

在Triton X-100/正己醇/环己烷/水反相微乳液体系中,分别采用一步法和两步法制备具有核/壳结构的磁性Fe3O4@SiO2复合纳米粒子.考察了搅拌方式和超声条件对一步法产物结构、形貌的影响,并与两步法进行了对比研究.通过XRD、FT-IR、DLS、TEM和VSM对复合颗粒进行了表征.结果表明,反相微乳液体系下,...     

Triton X-100/正构醇/石油醚/水反相微乳液性质的研究

通过测定微乳液的电导率值,确定配制W/O型Triton X-100/正构醇/石油醚/水微乳液的最大增溶水量;根据微乳液含水量与电导率关系曲线及体系的拟三元相图,讨论了正构醇种类、正构醇含量、乳化剂与油相质量比对W/O型微乳液的结构、电导率、增溶水量的影响。结果表明:乳化剂与油相质量比大于1时,正戊醇、正己醇和正庚醇为助剂配制的Triton X-100/正构醇/石油醚/水体系微乳液有较大的增溶水量,而乳化剂与油相质量比大于1.5时,以正丁醇为助剂配制的Triton X-100/正构醇/石油醚/水体系微乳液才有较大的增溶水量;正构醇的链长及加入量影响微液滴界面膜的强度,从而影响微乳液的增溶水量、电导率及微乳液形成区域的大小;对于Triton X-100/正构醇/石油醚/水体系,正戊醇是形成W/O型微乳液的较好助剂,当正戊醇与Triton X-100的质量比为0.5时,W/O型微乳液的形成区域最大。     

微乳液法制备无定形纳米二氧化硅

采用Triton X-100／正己醇／环己烷／氨水体系配制反相微乳液，在碱性条件下正硅酸乙酯在反相微乳液中发生受控水解，合成了具有无定形结构的球形二氧化硅纳米粒子。通过红外光谱（FT-IR）、X衍射（XRD）、透射电镜（TEM）分别对样品的结构及形貌尺寸进行了表征和分析。结果表明：改变表面活性剂加入量可以得到不同粒径（50～110nm）、不同粒度分布及不同分散程度的球形二氧化硅纳米粒子。随着表面活性剂在微乳液中体积分数的增大，二氧化硅纳米粒子的粒径先减小后增大，团聚程度也呈现先减小后增大的趋势。当表面活性剂在微乳液体系中的体积分数为20％时，所合成的二氧化硅纳米粒子粒径最小（50nm），粒度均匀且呈现出良好的分散性。     

反相微乳液法制备纳米氧化镁颗粒及其反应机理研究

通过聚乙二醇辛基苯基醚(Triton X-100)/正丁醇/正庚烷/水溶液形成的反相微乳体系,合成了MgO纳米粒子,对前驱体进行热分析,确定了合适的煅烧温度为600℃。并对产物的结构、粒度和形貌进行了表征,考察了各因素对纳米氧化镁粒子尺寸形貌和紫外屏蔽性能的影响。控制微乳液中水与表面活性剂的质量比(w0)为15、煅烧温度600℃、陈化时间15h可得到分散性好、粒径分布均匀的MgO纳米粒子。     

制备纳米BaSO4的W/O微乳液体系组成及稳定性

以Triton X-100/正己醇/环己烷/水制成W/O微乳反胶团体系，通过测定体系的电导率和观察液晶相的出现确定相点绘制了各体系的拟三元相图，研究了温度、盐浓度和油相组分对W/O微乳液体系稳定性的影响.实验发现助表面活性剂与表面活性剂的配比对微乳液的稳定性有显著影响.随着温度的升高，W/O微乳液稳定区域减小，可通过升高温度对微乳液进行破乳；与以纯环己烷为油相的体系相比，油相中含有少量正己烷的体系具有更优异的性质.所得结果为利用该W/O微乳液体系制备纳米颗粒提供了基础数据.     

Pb4[Ce(Ⅳ)W10O33]·32H2O纳米粒子的制备

以Triton X-100/n-C10H21OH/H2O体系W/O微乳液为基础,分别以K8[Ce(Ⅳ)W10O33]·32H2O 和Pb(NO3)2水溶液代替组分水制备W/O微乳液.然后将两种微乳液混合,得到黄色沉淀的Pb4[Ce(Ⅳ)W10O33]·32H2O纳米粒子,同时有少量纳米管生成.经电镜分析所得Pb4[Ce(Ⅳ)W10O33]·32H2O纳米粒子为粒径低于5 nm的圆球状颗粒,所得Pb4[Ce(Ⅳ)W10O33]·32H2O纳米管管长约为50 nm,管径约为5 nm.并用TG-DTA和Raman对该化合物进行了表征.     

热处理对微乳液法制备纳米氧化镍的影响

微乳液法是近年来制备纳米颗粒的有效方法之一，具有装置简单，操作容易，微粒可控等优点。以氯化镍和氨水为原料，以Triton X-100／环己彬正己醇／水为反相微乳体系，成功制备出纳米氧化镍前驱体，然后对前驱体进行热处理，得到纳米氧化镍粉末，系统考察了热处理对纳米氧化镍颗粒形貌、粒径分布的影响。结果显示，利用微乳液法制备的氧化镍纳米颗粒大小、形态及分散性优于经热处理后的粉末；X射线衍射谱及透射电镜显示，热处理后的氧化镍粉末粒径随着热处理温度的升高而增大。     

双微乳液法制备纳米硫酸钡颗粒

在水溶液/Triton X-100/正己醇/环己烷组成的反相微乳液中,以氯化钡和硫酸钠为原料,通过沉淀反应,制备出类球形BaSO_4纳米颗粒,并通过XRD、SEM、TEM、FTIR对其进行表征。考察了三种反应方式、水/Triton X-100摩尔比(R)、反应物浓度以及助表面活性剂/表面活性剂摩尔比(P)对纳米BaSO_4颗粒大小和形貌的影响。同时考察了R对微乳液液滴大小和粒径分布的影响,并通过动态光散射技术(DLS)对微乳液液滴进行测定。实验结果表明:室温条件下,采用双微乳液法,R=17.97,P在2.11~4.22之间是纳米BaSO_4颗粒合成的最佳反应条件,反应物浓度对BaSO_4颗粒的大小和形貌几乎没有影响。在该反应条件下,合成出的类球形BaSO_4粒径为18~22 nm,产率可达87.5%。     

微乳液法制备纳米粒子的研究进展

微乳液是一种具有热力学稳定性的单分散体系，其分散质点为纳米量级，它能够为纳米粒子的制备提供理想微环境：介绍了微乳液的性质以及利用微乳液制备纳米粒子的原理和方法，并讨论了利用微乳液制备纳米粒子过程中的各种影响因素。     

微乳液法制备纳米二氧化硅及表征

制备Triton X—10/正辛醇/环己烷/水(或氨水)油包水(W/O)型微乳液,讨论了微乳液相关性质与含水量的关系;以正硅酸乙酯(TEOS)为硅源,在制备的微乳液中受控水解制得纳米SiO2粒子,并用FT—IR、TEM、比表面测定进行表征;结果显示含水量和硅源浓度与粒子尺寸相关,TEM照片显示粒径40~80 nm。     

微乳液法制备条件对纳米SiO_2粒子形貌和粒径分布的影响

研究TritonX - 10 0 /正辛醇 /环己烷 /水 (或氨水 )微乳液稳定相行为与制备条件的关系 ,发现K〔m(TritonX - 10 0 )∶m(正辛醇 )〕 =1 5 ,而水相是氨水时微乳液系统有较宽单相W/O型微乳区 ,是正硅酸乙酯 (TEOS)水解制备纳米SiO2 粒子的适宜介质系统。在h〔n(H2 O)∶n(TEOS)〕 =4 ,R〔n(H2 O)∶n(TritonX - 10 0 )〕 =6 5和K =1 5的条件下 ,TEOS受控水解制得疏松球形无定形晶态SiO2 粒子 ,粒度分析表明 99 7%粒径为 4 0～ 5 0nm     

两种反相微乳液体系合成纳米羟基磷灰石的比较

制备了两种稳定的CTAB/正丁醇/正己烷/水体系和TritonX-100/正己醇/环己烷/水反相微乳液体系,研究了微乳液组份的浓度和比例对微乳液性质的影响,比较了两种反相微乳液体系的三元相图,用“微反应器”合成了纳米羟基磷灰石(HAP)粉体,比较了HAP颗粒在X-射线衍射、TEM、SEM表征中的异同。两种体系都表明反向微乳液法可以有效地控制和改变HAP的分散性和粒度大小。     

Catalytic Hydrogenations in Microemulsion Systems with Rh-TPPTS: Partial Hydrogenation of Sunflower Oil

The effect of the P/Rh ratio and the surfactant concentration on the partial hydrogenation of sunflower oil in Triton X-100 microemulsion systems with the water-soluble catalyst complex Rh-TPPTS has been studied. An unusual hindering effect of the surfactant on the production of elaidic acid and stearic acid as the oil is hydrogenated was observed. When increasing the concentration of Triton X-100 in the reaction medium from 3 to 15 wt%, the content of elaidic acid and stearic acid were lowered 21 and 34%, respectively. The maximum content of oleic acid was attained when the concentration of Triton X-100 was 15 wt%, obtaining a high content of 51.8% of oleic acid. When the ligand/metal ratio was higher, the reaction was slower but more selective to oleic acid. The Rh-TPPTS catalyst could be recycled up to 3 times after hydrogenation of sunflower oil by extracting the oil phase of a three-phase microemulsion system, observing a continuous deactivation of the catalyst.     

新型吖啶-二氧化硅荧光纳米颗粒的合成及表征

利用油包水的反相微乳液法,运用TritonX-100（曲拉通X-100）/正己醇/环己烷微乳液自组装体系,分别以吖啶、9-氨基吖啶、9-（2-氨基苯胺基）吖啶为核包覆SiO2,制备得到核壳型荧光氧化硅纳米颗粒。该方法克服了传统方法荧光试剂泄露的问题。透射电子显微镜检测和荧光光谱分析表明,所制得的纳米颗粒荧光强度高,荧光性质稳定,具有潜在生物亲和性,可望作为新型的荧光标记物。     

Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

Sulfur nanoparticles were synthesized from hazardous H₂S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe³⁺–malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 and n-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H₂S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5–15 nm) as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that of colloidal sulfur.     

Phase inversion temperatures of triton X-100/1-butanol/hydrocarbon/water systems

The formation of a water-in-oil (w/o) microemulsion in Triton X-100/1-butanol/alkane/water systems was investigated at 25.0±0.1°C. Phase inversion temperatures in hydrocarbon-water microemulsions stabilized with Triton X-100 were determined for different hydrocarbons. It was found that the more soluble the alkane (oil), functioning as a nonionic emulsifier, the lower was the phase inversion temperature, above which oil-in-water type microemulsions invert to w/o type. The effect of the presence of cosurfactant was studied. No phase inversion was observed in the absence of cosurfactant. The effect on phase inversion temperature of decreasing or increasing the temperature was evaluated. By definition, phase inversion was not affected by different temperatures.     

Microemulsion Extraction of Monascus Pigments from Nonionic Surfactant using High Polarity of Diethyl Ether as Excess Oil Phase

Stripping of organic compound from nonionic surfactant micelle aqueous solution is indispensable for many industrial processes. In this paper, a relatively high polarity diethyl ether was screened for forming Winsor I microemulsion, which was used for stripping of organic compound from nonionic surfactant. Setting up extractive fermentation of Monascus pigments in Triton X-100 aqueous solution as a model, cloud point extraction of Monascus pigments from fermentation broth, and back-extraction of Monascus pigments from the coacervate phase of cloud point system by Winsor I microemulsion were conducted. Monascus pigments were successfully separated from nonionic surfactant into the excess diethyl ether phase.     

不同因素对CTAB/TX-100微乳液相图的影响

用ε-β"鱼状"相图法研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)与非离子表面活性剂辛基苯酚聚氧乙烯(10)醚(TX-100)以不同摩尔比复配形成的CTAB/TX-100/醇/油/NaCl水溶液微乳液体系的相行为和增溶性能.结果表明,随着醇浓度的增加,体系由水包油型(O/W)(winsor Ⅰ or (2-)...     

The Effect of Surfactant Adsorption at a Glassy Carbon Electrode on Electrochemical Oxidation of Propyl Gallate

The electrochemical oxidation of propyl gallate (PG) in various surfactant solutions (AOT, Triton X-100 and CTAB) and microemulsions stabilised by the anionic surfactant SDS was investigated using cyclic voltammetry. This method has been widely applied to determine the role of microenvironment on antioxidative properties of natural and synthetic substances used to protect food and other products against oxidation. In general, the addition of surface-active agents to the system makes the oxidation of propyl gallate more difficult. The peak potential is shifted to more positive values due to the interaction of the electroactive substance with the surfactant structures at the electrode and with micelles in the bulk solution. In microemulsions the oxidation process is even more difficult than in the surfactant containing solutions. The oxidation potential increases significantly when the O/W microemulsion converts to W/O microemulsion through the bicontinuous phase.