单分散TiO2亚微米球的制备与表征

采用乙腈与乙醇混合溶剂体系制备出了单分散的亚微米级TiO2球形胶体颗粒, 并对乙腈相对含量以及实验温度等参数的影响进行了研究. 结果表明5 ℃下乙腈相对含量为70%时可制得高质量的单分散胶体颗粒. 通过TEM、SEM、粒度分析等表征手段, 表明所得胶体颗粒平均直径约为540 nm, 标准偏差在5%以内, 颗粒的多分布系数为0.013, TG-DSC分析表明胶体颗粒为含水量很少的水合TiO2; XRD分析表明单分散TiO2胶体颗粒在600 ℃高温烧结由无定型转变为锐钛矿型, 在900 ℃高温烧结则开始出现金红石型.     

胶体与界面化学──一门古老而活跃的学科

胶体和界面化学是研究胶体分散体系和界面现象的一门科学,根据分散性来定义,凡是在固、液、气相中含有尺寸在1 nm到100乃至1000 nm的固、液、气微粒的体系(气/气体系除外,因无界面)均属胶体科学研究的范围.由于这些体系具有巨大的界面,离开界面的研究就无法理解胶体的各种现象.因此这门科学便称之为胶体与界面化学.     

胶体与界面化学

正胶体与界面化学是研究分散体系的物理化学性质和界面现象的科学1,2。该学科与实际结合紧密,并与其他学科密切相关,其基本原理在物理化学的各分支学科中最具基础性、理论性和应用性。近年来,我国学者在胶体分散体系与界面化学领域的研究中取得了突破性的进展,很多研究结果得到了国际同行的关注和认可,为提升我国在该领域的国际学术地位起到了重大作用。然而,由于国内学者更加关注纳米材料、能源、生物医药等领域的前沿研究,相较于国际上在胶体与界面化学领域的研究,国内的研究方向也有所偏移。     

聚甲基丙烯酸β羟乙酯在聚乙烯膜上辐射接枝物的形态结构

本文用透射电子显微镜(TEM),光学显微镜(OM),小角X射线散射(SAXS)等方法研究了聚甲基丙烯酸β羟乙酯(HEMA)在聚乙烯(PE)膜上辐射接枝物的形态结构.观察了微相结构随接枝条件变化规律.HEMA为支链的接枝共聚物的基本形态是高度分散的HEMA微区(约几百A)存在于PE连续相中的两相体系.随接枝量增加,微区形态发生变化.SAXS结果进一步证实了接枝共聚物相分离的形态结构,并利用Tsvankin-Buchanan公式计算了共聚物的长周期、无定形层厚及一维结晶度.     

胶体颗粒稳定的界面及胶体颗粒在界面的相互作用（英文）

胶体颗粒稳定的分散体系如乳液、泡沫和气泡等体系在众多研究领域吸引了越来越多的关注。胶体颗粒的吸附机理、油-水界面和气-水界面的胶体颗粒稳定机制以及吸附于界面的胶体颗粒乳液相互作用对这些分散体系的实际应用至关重要。虽然在相关方面已经有众多研究,胶体颗粒对界面的稳定作用和胶体颗粒之间的相互作用仍然存在很多问题,值得进一步研究。在本文中,我们首先系统地回顾了历来胶体颗粒稳定的乳液和气泡体系的研究,并概括地介绍了在该领域内较为重要和较为成熟的研究进展,包括乳液、泡沫和液体弹珠等。人们早已认识到胶体颗粒在界面的吸附现象,在学术上的探讨也已经超过一个世纪。上世纪八十年代有研究者提出了定量的理论模型来描述这种现象。该理论从自由能降低的角度解释了为何胶体颗粒会吸附到界面上,并且能将胶体颗粒对两相的浸润性与乳液和泡沫体系的稳定性联系起来。在乳液稳定性方面,有大量的研究支撑了上述理论;研究者们制备了具有响应性的乳液体系,如pH/温度响应性。之后,我们讨论了吸附在界面的胶体颗粒的相互作用的最新进展,并提出了该领域内尚未解决的问题。由于需要精密的仪器和熟练的操作技巧,胶体颗粒在界面的相互作用实验和理论研究之间还存在巨大的差距。虽然弯曲界面更为常见,实验上通常采用水平界面作为模型界面来研究胶体颗粒在界面的相互作用。胶体颗粒在界面的引入会由摩擦导致电荷存在,这很可能是长程静电相互作用的原因。最后,我们介绍了胶体颗粒稳定的分散体系的在包埋、食品、控释和干水的制备等领域的应用。使用乳液液滴作为平台,是制备包埋体系的主要手段之一。吸附在界面的胶体颗粒,不仅可以稳定界面,也可以作为胶体微胶囊的壁材。使用自然来源的胶体颗粒为稳定颗粒,乳液体系可方便地应用于食品相关领域。近年来由于其全部由水相构成,水-水体系吸引了越来越多的关注。气-水界面与油-水界面具有相同的稳定机制,我们对一些基于气-水界面的应用进行了探讨。我们希望借由该篇文章鼓励更多的研究人员参与到胶体颗粒稳定界面的研究中来,并基于此开发出越来越多的新颖应用。     

高分子物理学系統講演

第十講 高分子溶液 1.高分子溶液与胶体的区別 溶液由溶质及溶剂组成,成为单相体系如蔗糖水溶液。胶体为两相体系如金溶胶等。这两种体系有原則上的差别,溶液在外界条件不改变时处于热力学平衡从态,可用热力学函数描述,如蒸气压、渗透压等。而胶体中有一相分散得很细不稳定,因微粒越小表面能越大,故胶体有減小相界面的趋向,卽胶粒的凝聚終     

中国化学会第十四届胶体与界面化学会议2013年7月21-25日,长春

会议主题:研讨胶体与界面化学的最新前沿问题和发展前景及其在科学和技术领域中的作用.会议内容及范围:(1)表面/界面与纳米结构材料;(2)溶液中的聚集与分子组装;(3)软物质与超分子组织化体系;(4)胶体分散与多组分体系;(5)胶体与界面化学中的理论问题;(6)胶体与界面化学技术、应用与产品.会议主席:郭荣通讯地址:扬州大学化学化工学院,扬州225002     

磺化聚苯乙烯胶体晶的红外光谱分析

单分散乳胶体系可以通过自组装形成有序的胶体晶结构 ,在窄波段光过滤器[1] 、生物医学传感器[2 ] 、智能化学传感器[3] 等领域具有重要的应用价值 .最近 ,人们以此有序结构作为模板 ,制备了有序孔材料[4～ 7] .另外 ,此有序结构在仿生学如模拟蛋白石等有序结构等方面也具有重要意义[8] .但是 ,一般的单分散体系如聚苯乙烯体系所形成的有序结构都属于硬性材料 ,缺乏对外场的响应特性 .此外 ,微球表面没有功能性基团 ,很难与其它物质兼容 ,这使得其作为模板合成其它复合材料的潜力大大降低 .本实验室通过对聚合物胶体晶进行改性 ,使其成为功…     

胶体晶体中的两种排列方式及堆积模式

由单分散的有机或无机粒子制备三维有序的胶体晶体越来越受到人们的关注 [1～ 3 ] ,单分散颗粒如何排布和堆积是形成三维有序胶体晶体的关键 .自然界中的蛋白石 (Opal)是由单分散 Si O2 粒子的三维有序堆积中渗入水溶性的硅酸盐固化而成的 .仿照自然界的模式由单分散的有机或无机粒子制备三维有序的胶体晶体是对当今科学技术的一个挑战 [4 ] .以胶体晶体为模板制备有机、无机、金属和陶瓷等的多孔材料在催化、吸附以及光子晶体等方面具有重要的应用前景 [5～ 9] .本文研究了以单分散的聚苯乙烯 -甲基丙烯酸甲酯 -丙烯酸 [P(St- MMA- AA)…     

中国化学会第十四届胶体与界面化学会议2013年7月21-25日,长春

会议主题:研讨胶体与界面化学的最新前沿问题和发展前景及其在科学和技术领域中的作用会议内容及范围:(1)表面/界面与纳米结构材料;(2)溶液中的聚集与分子组装;(3)软物质与超分子组织化体系;(4)胶体分散与多组分体系;(5)胶体与界面化学中的理论问题;(6)胶体与界面化学技术、应用与产品会议主席:郭荣通讯地址:扬州大学化学化工学院,扬州225002电子信箱:guorong@yzu.edu.cn     

Preparation and characterization of well-defined sterically stabilized latex particles with narrow size distribution

 The synthesis and comprehensive characterization of a purely sterically stabilized latex with narrow size distribution is reported. By use of non-ionic initiators no chemically bound surface charges are generated. Stabilization of the particles is achieved through use of a non-ionic surfactant having a double bond in the hydrophobic part which is chemically bound to the surface. Analysis of the latex particles thus generated by transmission electron microscopy, disc centrifugation, and small-angle X-ray scattering (SAXS) reveals that the size distribution is narrow (standard deviation between 6 and 10%). SAXS furthermore demonstrates that the surfactant is located in a thin layer on the surface. The interaction of the particles is purely repulsive as shown by the analysis of the turbidity of the latex. The systems obtained herein may serve as model systems of water-borne purely sterically stabilized colloid particles. Received: 23 December 1997 Accepted: 18 May 1998     

Transmission electron microscopy observations of composite polymer colloid nucleated by functionalized silica

In this work, functionalized nanometric silica particles were engaged in emulsion polymerization of ethyl acrylate. The morphological characterization of this composite material was performed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). We were particularly interested in the state of encapsulation of the silica particles and their distribution in the latex film. Initialy, we successively studied both components of the composite: polymer beads and silica particles differ by their size and also by their contrast. In addition, it was possible to perfrom dark field TEM to study this system of two amorphous phases because their respective amorphous halos are not too close. Hence, we investigated the colloid material in aqueous media and after film formation. Although no ideal encapsulation is observed in the colloid in aqueous media, the distribution of silica in the latex film is good. SAXS results are in good agreement with TEM observations.     

SURFACE STRUCTURE OF THE MICELLE OK AN AMPHOTERIC AMPHIPHILE DERIVED FROM LYSINE

ABSTRACT

Micelle structure in aqueous colloid of an amphoteric amphiphile N^αN^α-dimethyl-N^? -lauroyl lysine (DMLL), which was derived from lysine, was studied through light scattering, SAXS and a rheological method. The critical micelle concentration of the colloid system is 216 UM and the weight average molecular weight of the micelle is 2.40 × 10⁴, i.e. the aggregation number is 67.4. The diameter of the micelle is about 43.4 Å and the spherical micelle is likely to be retained in a concentration up to about 20 %, The SAXS measurements show that the electron density Fluctuation in the micelle is almost negligible and that the surface area of the micelle is approximately 3.5 times larger than that of a completely smooth sphere.     

L-苯丙氨酸衍生物与脂肪胺构筑双组分超分子凝胶

设计合成了系列单链L-苯丙氨酸衍生物,该系列衍生物单组分没有胶凝性能. 选择脂肪胺作为配对物,与L-苯丙氨酸衍生物组成双组分体系后能够胶凝许多有机溶剂形成凝胶. 流变学测试显示该凝胶体系弹性模量（G’）比粘性模量（G"）约高一个数量级,有着很好的机械性能,并且呈现出典型的类固体的流变学行为. 傅里叶变换红外（FT-IR）光谱、核磁共振（NMR）谱、小角X射线衍射（SAXS）和扫描电镜（SEM）结果表明,凝胶中胶凝剂分子形成纤维状或片层状的聚集体,羧基（―COOH）和氨基（―NH₂）的酸碱作用、酰胺基团间（―CONH―）的氢键作用以及分子间范德华作用力是形成该凝胶的主要驱动力. 凝胶中胶凝剂分子自组装形成具有周期性的层状有序结构,层状结构进一步组装形成纤维状聚集体,最终形成三维网状结构阻碍溶剂流动形成凝胶.     

SAXS测定二氧化硅胶体粒子结构

本文考察了正硅酸乙酯(TEOS)在碱性催化条件下通过水解和缩聚而制得的二氧化硅胶体的小角X-射线散射(SAXS)特征，通过散射数据对Porod负偏离的分析和校正，测定了胶体粒子的几何结构，包括胶团尺度分布、胶核尺度分布及平均界面层厚度，这有助于认识胶体的物理化学特征。     

Stacking structure of concentrated shear ordered dispersions by two scattering methods

In this paper, the ordering in concentrated charge stabilized colloidal dispersions is considered. Despite the impressive Bragg reflections obtained for shear ordered dispersions by light (LS), small-angle neutron (SANS), and small-angle X-ray scattering (SAXS), a number of open questions remain. Sheared dispersions are usually ordered in layers. For such systems, two questions arise: (1) What is the structure in a layer? (2) What is the stacking structure perpendicular to the layers? The second question requires a method to determine the structure perpendicular to the layers. Although originally interested only in structural aspects, we were forced to consider different methods. Two methods are treated both applicable to neutron and X-ray scattering from concentrated dispersions. One has been used by physicists and chemists for many years to determine the structure of crystals by sample rotation. In colloid science, we have used it previously in neutron and X-ray scattering. A second method is treated here which can be applied in small-angle scattering from a Couette cell. It gives the scattering intensity in a certain direction without sample rotation. Although very useful with the Couette cell, it cannot be found in any of the well-known references on colloid science. A theoretical explanation and experimental examples obtained by synchrotron X-ray scattering from a Couette cell are given in the paper.     

Effect of pH on colloidal properties of native ovalbumin aqueous systems

The effect of pH on the molecular shape and dispersed state of native ovalbumin molecules in 20 mM phosphate and acetic acid buffer solutions has been studied using small-angle x-ray scattering (SAXS) and a rheological method The degree of association of the OA molecule at the 0.5% colloid system increases slightly with decreasing pH, i.e., 2.10 at pH 7.0, and 2.88 at pH 4.0, and the radius of the OA molecule decreases slightly with decreasing pH, i.e., 24.5 Å at pH 7.0, and 22.0 Å at pH 4.0.The OA colloid shows apparent yield stress and rigidity which are due to a certain ordered arrangement of the molecules. The yield stress and the rigidity increase abruptly at a pH value near to an isoelectric point (ca. pH 4.4). In the dilute system this increment is attributed to the change in the ordered arrangement or in the interparticle interaction, and not to the change in the association state of the OA molecules. The values of the yield stress and the rigidity remain almost constant over a wide concentration range and this feature (an auto-controlled mechanism) is kept over a certain range of pH.     

蒙脱石细微结构对其水体系ζ电势的影响

胶体的ζ电势系指主体溶液与随粘粒一起运动的水膜之间剪切面位置的电势．（电势大小与粘粒在电场中双电层结构、水化膜厚度、反离子的浓度和性质等有关．蒙脱石晶体结构单元层是由两层SIO四面体中间夹一层AI－（OH）八面作层所构成．晶层沿a轴和b轴方向无限延伸，沿C轴品层间有一定间隙互相查置．op面体层中St可部分被AI所置换；／＼面体层中阳离子AI也可被较大半径的Fe、Mg离子所置换．晶格置换中，由于离子半径的差异，导致晶格发生某种畸变，同时，阳离子价态差异又造成结构层电性差异．常见的是高价态阳离子被低价态阳离子置换（…     

蒙脱石细微结构对其水体系ζ电势的影响

The zeta-potential of montmorillonite-water colloid systems of different districts and distinct types are different. In this study the zeta-potentials were determined for montmorillonitewater colloid system of different districts and types. The relationship of octahedral(Fe~(3+)+Mg~(2+)) and the cell parameter b0 dimension of montmorillonites with the zeta-potential of montmo rillonite-water colloid systems were discussed.