Triton X-100/C10H21OH/H2O体系微乳液与溶致液晶

关于离子型表面活性剂生成的微乳液与溶致液晶已有不少研究，非离子型表面活性剂生成的微乳液与港致液晶的应用正在引起人们的重视，但由于药物提纯的困难，对其物理化学性质的研究还不多见．本文以非离子表面活性剂TritonX－100／C10H21OH／H2O体系为例，研究了非离子型表面活性剂微乳液和溶致液晶的生成及其结构特性．1实验部分试剂ThitonX－100（Aldrich公司，分析纯）正癸醇（分析纯）、水为一次蒸馏水微乳液区域和层状液晶区域的确定方法及小角x射线衍射测定方法同文献，实验温度20±0．1℃．2结果与讨论2·IThtonX－100、CIOH…     

层状溶致液晶中Ag纳米粒子的掺杂

通过在具有长程有序结构的有机溶致液晶内嵌入预制的、表面性质可调控的银纳米粒子, 得到了亲水与亲油介观空间内同时嵌入纳米粒子的无机/有机杂合体. 掺杂前后液晶结构的变化和杂合体稳定性用小角X射线散射和偏振光学显微镜等进行了表征. 结果表明, 表面活性剂双层膜与导入纳米粒子间的立体化学匹配及相互作用是影响杂合体稳定性的重要因素.     

Igepal CO系列表面活性剂溶致液晶的结构特性

对壬基酚聚氧乙烯醚（IgepalCO）系列表面活性剂,生成何种溶致液晶与其EO基团数n有关,而在何浓度范围内生成溶致液晶则与生成溶致液晶的最低水含量及最大水增溶量有关．EO基团数n小于10时,生成层状液晶,n大于10时则生成六角状液晶,层状液晶两亲双层内,水与表面活性剂的最低摩尔比rmin和最高摩尔比rmax随EO基团数n增加分别是非线型增加与线型增加,在IgepalCO520（n＝5）中加入IgepalCO710（n＝10．5）,对层状液晶的生成无显著影响,在IgepalCO710中加入IgepalCO520,则对六角状液晶的生成产生显著影响,出现了六角状液晶向层状液晶的转变。     

小角X射线散射表征AOT/水层状溶致液晶的有序性

用小角X射线散射研究了AOT/水层状溶致液晶的有序性. 通过对散射曲线的解析, 讨论了表面活性剂浓度、温度和助表面活性剂等三个方面对溶致液晶层状相结构有序性的影响. 在一定的范围内, 提高温度, 改变表面活性剂浓度和加入少量助表面活性剂可使碳氢链排列由稀疏转变为密实, 层状相也相应地由“柔性双层”过渡到更加有序化的“平面双层”. 基于形状因子和体系内分子间作用力, 提出了层状相形成与有序化的机理, 同时采用分子模拟的方法展现了不同浓度下的液晶结构.     

磺酸型双子表面活性剂的溶致液晶结构研究

合成了一种磺酸型双子表面活性剂6,6 -(丁基-1,4-二基双氧)双(3-壬基苯磺酸)(9BA-4-9BA), 利用偏光显微镜和X射线衍射分析仪研究了其在水溶液和乙酸乙酯溶液中的溶致液晶结构变化. 结果表明, 9BA-4-9BA在两种溶剂及其混合溶剂中均可出现溶致液晶态结构, 并且双子表面活性剂的溶致液晶相态与溶液浓度和溶剂种类密切相关. 随着浓度增加, 9BA-4-9BA水溶液溶致液晶结构由立方相经由片层立方相转变为层状液晶相, 乙酸乙酯溶液中主要以层状液晶相存在.     

溶致液晶体研究及其在三次采油中的应用

研究了石同磺酸盐／正戊醇／水的三元体系和石油磺酸盐／癸烷／正戊醇／水的拟三元体系相图中的液晶区域,揭示了不同组分对液晶区域大小的影响以及液晶的流变性和液晶的结构,在三次采油中,用六角状溶致液晶体系代替三元复合驱体系进行化学驱油,虽然驱油效率更高,但需进一步降低液晶驱油体系的成本。     

层状溶致液晶中磁性纳米粒子掺杂的研究

选择非离子表面活性剂十二烷基(4)聚氧乙烯醚(C₁₂E₄)与H₂O构成的溶致液晶(LLC)层状模板, 掺杂油酸铵包覆的Fe₃O₄亲水性磁性纳米粒子, 构建稳定的有机/无机杂合体. 用透射电镜(TEM), X射线粉末衍射(XRD), 偏光显微镜(POM), 小角X射线散射(SAXS)和振动探针式磁强计(VSM)等对粒子及掺杂前后的层状液晶相结构变化进行表征. 结果表明, 粒子掺入使LLC模板的层间距产生了改变, 同时增强了体系有序性．通过对杂合体表征结果的分析, 阐述了模板与粒子间相互作用的机理.     

溶致液晶及其在纳米结构材料合成中的应用*

有序纳米结构材料是一类具有广泛应用前景的新材料,在分离、催化、传感器等领域的应用潜力巨大。近年来,利用溶致液晶模板合成纳米结构颗粒和薄膜材料的研究取得了一系列重要进展,包括新纳米结构金属和半导体材料的合成、由过渡金属水合物与表面活性剂构建的新液晶体系、溶致液晶与其它模板结合制备具有多级孔结构的新材料、影响液晶体系及纳米结构材料有序性与稳定性的关键因素、以及纳米结构形成机理等方面的内容。本文就上述几个方面的近期研究成果进行了总结与综述,并展望了利用溶致液晶模板合成纳米结构材料需要进一步深入开展的内容,有助于化学、化学工程和材料科学等领域的相关研究工作。     

溶致液晶模板电化学沉积纳米材料

本文综述了以小分子表面活性剂构成的溶致液晶作模板,采用电沉积方法制备金属、半导体、导电聚合物的纳米膜、纳米线等材料的研究进展.对影响沉积产物形貌和性能的各因素进行了分析,展望了溶致液晶模板电沉积纳米材料的发展趋势.     

正、负离子表面活性剂混合体系溶致液晶生成的相行为

研究了烷基(C8,C12,C14)三甲基溴化铵、烷基(C12,C14)溴化吡啶与烷基(C8,C12)硫酸钠混合体系溶致液晶形成的条件与结构的变化.在高浓度的水溶液中,随着正、负离子表面活性剂摩尔比接近于1,液晶结构由六角相过渡为层状相.表面活性剂非极性链长改变,对相行为影响显著,短碳链的正、负离子表面活性剂混合体系,在等摩尔比时,体系为层状液晶或立方液晶为主,夹杂少许沉淀.随碳链增长,两类表面活性剂间的静电吸引效果表现为生成沉淀的摩尔比例范围变宽,沉淀量增多,共存的液晶相减少,甚至消失.若只改变正离子的极性头基,季胺盐比吡啶盐与烷基硫酸盐的作用要强,形成不溶物的混合摩尔比例范围更宽.     

New one-pot technique to introduce charged nanoparticles into a lyotropic liquid crystal matrix

We present a new method to incorporate hydrophilic charged nanoparticles into the lyotropic liquid crystal (LLC) template. This method is based on the effect of the polymer-induced phase separation (PIPS) and consists of two steps. In the first step, the nanoparticles are mixed with a surfactant micellar solution. In the second step, upon addition of polymer, phase separation is induced and the LLC phase doped with the nanoparticles is formed. Columnar hexagonal and lamellar LLC templates are obtained with the PIPS method. The ordering of the LLC phase can be controlled by the amount of polymer added to induce phase separation. The method works both for the system of nonionic surfactants and polymers and ionic surfactants and polyelectrolytes. We demonstrate that the PIPS method enables the fabrication of the LLC templates doped with positively or negatively charged nanoparticles as well as with a mixture of oppositely charged nanoparticles in arbitrary proportions.     

溶致液晶中金属纳米粒子的掺杂及其作用机制研究

在用琥珀酸二异辛酯磺酸钠(AOT)构建的具有长程有序结构的层状溶致液晶内, 用不同方式导入预制的亲油或亲水贵金属纳米粒子, 可得到纳米粒子分布在不同介观空间内的无机/有机杂合体. 依据小角X射线散射和偏光显微镜结果, 通过分析掺杂纳米粒子与液晶模板的相互作用, 对掺杂前后体系结构的变化及制得杂合体的稳定性进行了表征. 结果表明, 除考虑掺杂粒子与层状模板空间的匹配外, 体系中静电斥力、范德华引力和Helfrich涨落力之间的平衡是维持液晶结构稳定的基本条件.     

表面活性剂溶致液晶的流变学性质*

系统阐述了三种溶致液晶(六角状、立方状和层状液晶)的流变性质,概括了各自的流变性特点并给出了其理论模型,特别对立方相的流变学模型和层状相的剪切诱导转变作用进行了较详细的说明.讨论了因为这种转变而导致的囊泡的形成,并且在表面活性剂和嵌段共聚物中均可观察到剪切诱导的结构转变.     

仿生溶致液晶体系的构建与掺杂

本文综述了以类脂为基础的仿生溶致液晶体系的构建与掺杂，对掺杂物质与液晶模板之间的相互作用进行了分析，并展望了仿生溶致液晶体系在合成新型功能材料、生物学和医学等领域应用的发展前景。     

Structural,thermal, dielectric and optical behaviour investigations of water-free ZnO/lyotropic liquid crystal nanocolloids

ABSTRACT

Zinc oxide (ZnO) nanoparticles of spherical symmetry (average size of ≈ 20 nm) have been synthesised via a non-aqueous lyotropic liquid crystalline (LLC) templating process. Lyotropic liquid crystalline nanocolloids are prepared via dispersing 0.05, 0.1 and 0.5 wt.% ZnO nanoparticles in non-aqueous lyotropic phase. No structural phase change has been seen with the doping of nanoparticles as stable lamellar phases are observed in all the cases. Stability of the lamellar structure and orientation of the ZnO nanoparticles in the liquid crystalline matrix may be attributed to the interfacial surface charge interactions. A significant increase and pronounced dispersion in dielectric permittivity of the ZnO/LLC nanocolloids could be the result of parallel coupling among guest/host, higher dipole- moment of the ZnO nanoparticles and Maxwell-Wagner polarisation. The variation of relaxation parameters has also been discussed and correlated with the dielectric and structural parameters. ZnO/lyotropic nanocolloids devices exhibit dc conductivity of the order of 10^?5S/m owing to the increase in the number of ions (of the order of 10¹⁹m^?3) in the doped systems. Nanocolloids exhibits, the refractive index of range 1.40 to 1.45 and the wide bandgap of the range 4.1–4.5 eV.     

Doping silver nanoparticles in AOT lyotropic lamellar phases

The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the first time. The change of template structure after doping and the stability origin of dual-doped system are characterized by small angle X-ray scattering and polarized optical microscopy. Results show that the interaction and space matching between surfactant bilayers and doped particles are key factors to obtain stable hybrid.     

Fabrication of mesoporous Pt nanotubes utilizing dual templates under a reduced pressure condition

Pt nanotubes with mesoporous walls have been successfully prepared for the first time by the combination of hard templates (porous anodic alumina membranes, PAAM) and soft templates (lyotropic liquid crystals, LLC).     

Electrochemical synthesis of mesoporous Pt-Au binary alloys with tunable compositions for enhancement of electrochemical performance

Mesoporous Pt-Au binary alloys were electrochemically synthesized from lyotropic liquid crystals (LLCs) containing corresponding metal species. Two-dimensional exagonally ordered LLC templates were prepared on conductive substrates from diluted surfactant solutions including water, a nonionic surfactant, ethanol, and metal species by drop-coating. Electrochemical synthesis using such LLC templates enabled the preparation of ordered mesoporous Pt-Au binary alloys without phase segregation. The framework composition in the mesoporous Pt-Au alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt-Au alloys with low Au content exhibited well-ordered 2D hexagonal mesostructures, reflecting those of the original templates. With increasing Au content, however, the mesostructural order gradually decreased, thereby reducing the electrochemically active surface area. Wide-angle X-ray diffraction profiles, X-ray photoelectron spectra, and elemental mapping showed that both Pt and Au were atomically distributed in the frameworks. The electrochemical stability of mesoporous Pt-Au alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt-Au alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt-Au alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.     

Synthesis and lyotropic liquid crystalline behaviour of a taper-shaped phosphonic acid amphiphile

A taper-shaped phosphonic acid, 3,4,5-tris(dodecyloxy)phenylmethylphosphonic acid ( 1 ), was synthesized; its lyotropic liquid crystalline (LLC) behaviour and its ability simultaneously to order and acid-dope polyaniline were examined. It was found that the ability of 1 to form LLC phases in the presence of several hydrophilic solvents is restricted by strong intermolecular interactions between the phosphonic acid head groups (presumably H-bonding). The amphiphile exhibits poor miscibility with pure water and even with strong H-bonding organic solvents such as DMF. However, it forms a lamellar mesophase in the presence of aqueous acid. Upon deprotonation of the phosphonic acid head group with NaOH, the resulting disodium salt of the amphiphile is able to form a well defined lamellar phase with pure water. The propensity of 1 to form lamellar phases is somewhat unusual since its tapered molecular shape should direct it to form an inverted hexagonal LLC phase. These results suggest that intermolecular head group interactions are more important in determining the overall LLC behaviour of this phosphonic acid amphiphile than are the hydrophobic character and shape of the organic tail system. Compound 1 was also found to be sufficiently acidic to act as an acid dopant for the conjugated polymer polyaniline in the emeraldine base form. LLC acid 1 induces the resulting polymeric salt to form an electrically conductive LLC complex with an extended lamellar microstructure. The bulk conductivity of the resulting nanostructured polyaniline salt was found to be only in the semiconducting regime (10 -5 Scm -1 ), due to an unfavourable polyaniline chain conformation in the LLC complex.