聚氧乙烯型非离子表面活性剂Triton X-100和Tween-60的毛细管超临界流体色谱分析

对辛基苯酚惭烯型非离子表面活性剂ＴｒｉｔｏｎＸ－１００和聚氧乙烯失水山梨醇脂肪?酯型非离子表面活性剂Ｔｗｅｅｎ－６０进行毛细管超临界流体色谱法（ＣＳＦＣ）分析条件的研究，用ＣＳＦＣ连接通用型ＦＩＤ检测器研究了二种表面活性剂的组成和分子量，实验结果表明，ＴｒｉｔｏｎＸ－１００中含量最多的低聚物的ＥＯ数（聚合的环氧乙烷数目）为９－１０，分子量约６００，Ｔｗｅｅｎ－６０的分子量约为１５００，与理论计算值     

液膜稳定性的研究

利用单滴法对三种表面活性剂的液膜体系的稳定性进行了研究，重点考察了载体的影响，讨论了介质与表面活性剂，介质与载体，载体与表面活性剂的相互作用对液膜稳定性的影响，并根据膜强度数据，给出了液膜稳定的条件。     

液膜稳定性的研究

利用单滴法对三种表面活性剂的液膜体系的稳定性进行了研究，重点考察了载体的影响，讨论了介质与表面活性剂，介质与载体，载体与表面活性剂的相互作用对液膜稳定性的影响，并根据膜强度数据，给出了液膜稳定的条件。     

表面活性剂疏水链长对高温下泡沫稳定性的影响

选用不同疏水链长的α-烯烃磺酸盐(AOS)形成泡沫, 分别用泡沫衰减法和泡沫岩芯封堵法测定不同温度下的泡沫稳定性, 并采用动态表面张力、界面流变、分子模拟等方法研究了表面活性剂在气/液界面的吸附行为和界面吸附层的性质, 分析了高温下泡沫的稳定机制. 实验结果表明, 在高温下, 极性头的“锚定作用”减弱, 表面活性剂疏水链难以在气液界面保持以直立状态吸附, 疏水链碳数大于20的表面活性剂分子难以分立吸附, 其疏水链相互交叉缠绕, 增强了泡沫膜的强度, 减缓了气体通过液膜的扩散, 形成的泡沫在高温下具有较好的稳定性.     

单烷基乙二胺稀水溶液头基相互作用自组装形成 双分子膜

提出普通表面活性剂(单链两亲分子)亲水头基相互作用诱导疏水尾链平行聚集形成双分子膜的新机制。设计和合成了系列单烷基取代乙二胺C~nH~2~n~+~1NHC~2H~4NH~2(n=8,12,14,16,18)。通过电镜形态,分散液凝胶/液晶相变和对应铸膜的二维双层结构,表明单链两亲分子头基相互作用和脂链引入刚性片断一样,两者形成的双分子膜具有类似的结构和性能;展示了各体系取代乙二胺双层结构和性能的密切联系。指出了广泛认同的单链两亲分子形成双分子膜必须引入刚性片断的单一成膜机制的片面性,为组装新一类功能头基表面活性剂双分子膜独辟蹊径。     

含Gemini表面活性剂结构单元的新型两亲聚电解质的合成及聚集行为

分别将Gemini型单体1,3-双(二甲基十四烷基溴化铵)-2-丙烯酰氧基丙烷(14G)或1,3-双(二甲基十六烷基溴化铵)-2-丙烯酰氧基丙烷(16G)与丙烯酰氧乙基三甲基氯化铵(DAC, D)共聚合反应, 合成了新型含Gemini表面活性剂结构单元的两亲性阳离子聚电解质(D14G和D16G). 采用稳态荧光、电导、动态光散射及透射电镜等手段研究了这些聚电解质在水溶液中的聚集行为. 结果表明, 临界聚集浓度(CAC)随着Gemini型表面活性剂单元含量的增加而减小, 同时随着Gemini型表面活性剂单元中疏水碳链长度的增加而降低. 这些聚电解质在水溶液中同时存在分子内和分子间两种类型的聚集体, 而且碳链越长, 形成分子内聚集体的倾向越强. 随着Gemini表面活性剂单元含量的增加, D14G溶液中聚集体的流体动力学半径(Rh)也有所增大, 而D16G溶液中的聚集体的流体动力学半径(Rh) 却略有减小.     

模拟乳状液中微小液滴间的相互作用力

对商品化的DCAT21表面/界面张力仪进行改造, 用于直接测量液滴间相互作用力, 同时用数码摄像头Digital 3.0观察记录两液滴接近, 挤压, 排液, 聚并等过程. 研究发现, 溶液中微小液滴间的相互作用力随距离的变化曲线能够提供分散液滴的行为特征信息: 曲线上不同阶段的斜率反映力的大小; 从液滴接触后到聚并前的挤压距离反映液滴的稳定性. 表面活性剂种类不同, 对两液滴聚并所起的稳定作用不同, 非离子表面活性剂具有较好的稳定作用. 溶液中聚合物分子在薄液膜中形成具有一定强度的层状结构, 阻碍液滴聚并, 受力曲线呈阶梯状.     

适用于液膜分离的磺化液体聚丁二烯型聚合物表面活性剂

液膜技术作为一种高效、快速的分离工艺已应用于工业废水处理,分离和浓缩金属离子和某些有机化合物,它的成功应用有赖于性能优良的表面活性剂的研究和开发。聚合物表面活性剂可增加液膜的强度,可提高所得乳液的稳定性,受到     

含磺酸盐基两性分子／聚乙烯亚胺LB膜的聚集结构

气液界面聚离子复合结构的形成能减弱两性分手亲水基间静电排斥作用，增加单分子膜的稳定性和累积性能．Ｘ－射线衍射结果表明，纯水和聚乙烯亚胺水溶液表面上的ＺＣ１４ＳＮａ单分子膜在聚苯乙烯基片上累积成Ｙ型膜，两种ＬＢ膜的等同周期差约为０．３０ｕｍ．     

胆固醇对卵磷脂囊泡稳定性的影响

采用透射电子显微镜研究了Gemini表面活性剂诱导卵磷脂囊泡结构改变的机理, 用Langmuir膜天平研究卵磷脂和胆固醇的不溶单分子混合膜在气-液界面的行为和混合膜分子间的相互作用, 并结合动态光散射技术和停留法探讨胆固醇对Gemini表面活性剂诱导卵磷脂囊泡结构改变的影响. 从电镜结果可以推测带正电荷的Gemini表面活性剂分子会嵌入到带负电荷的卵磷脂囊泡双分子层的外层, 囊泡的双分子层之间的相互吸引力使双分子层的厚度减少, 由于嵌入的表面活性剂分子在囊泡的双分子层中分布是不均匀的, 这种分布的不均匀性必然会导致双分子层厚度的不均匀, 从而使囊泡破裂. 混合膜的过剩面积和动力学结果表明, 胆固醇和卵磷脂是相互吸引的, 即胆固醇的加入使卵磷脂囊泡更不容易被表面活性剂破坏.     

Mechanism of nitromethane liquid membrane oscillator containing sodium oleate

The oscillatory behavior of a liquid membrane oscillator with anionic surfactant was investigated in order to understand the oscillation mechanism at the molecular level. As a theoretical framework, an approach based on chemical kinetics laws has been used. The chosen system involved nitromethane with 2,2(')-bipyridine as liquid membrane. The aqueous donor phase contained sodium oleate and butanol, while sodium chloride was added to the aqueous acceptor phase. It was established that the oscillations take place exclusively at the aqueous acceptor phase/membrane interface. Therefore, liquid membrane oscillators with anionic surfactants behave the same way as oscillators with cationic surfactants as to the location of oscillations. An oscillation mechanism involving three stages is proposed and confirmed by numerical simulations. The oscillations of electrical potential differences between the two aqueous phases are produced by sudden adsorption and desorption of anionic surfactant in solvated form and butanol at the acceptor/membrane interface. The whole process is controlled by the slow diffusion of these species across the liquid membrane. The chaotic character of the oscillations was demonstrated by Lyapunov exponents obtained from the strange attractor of the system.     

泡沫的稳定性及液晶对它的影响

泡沫体系的表面张力、粘度,表面粘度以及液晶相的存在对泡沫的稳定性皆有影响。消泡剂可改变上述性质。本文报导聚氧乙烯辛基酚(TritonX-100),十二烷基硫酸钠(SDS),油酸三乙醇胺(TEAOL)和卵磷脂等起泡剂在均相溶液及有液晶存在时产生泡沫的稳定性,观察硅油的消泡作用。     

液膜萃取法回收磷酸体系中的微量镧

通过斜率分析法研究了P204和TOPO从磷酸体系中液液萃取微量镧的反应机制和热力学,推测出一种可能的反应历程和萃合物结构,得到萃取反应式和反应的平衡常数K=104.502,焓变ΔH=-13.02 kJ.mol-1,自由能ΔG=-25.686 kJ.mol-1,熵变ΔS=0.0425kJ.(mol.K)-1。在液液萃取反应机制研究的基础上,采用液膜萃取法进行磷酸体系中微量镧的富集回收研究,考察了载体P204(2%～10%w/w)和TOPO(1%～10%w/w)、表面活性剂磺化聚丁二烯LYF(1%～10%w/w)、内萃取剂HCl(1～5 mol.L-1)和水乳体积比A/O(2:1～7:1)对液膜萃取收率及稳定性的影响。在最优条件下,可回收94.10%～95.94%的镧,并且膜溶胀率为8%～17%,破损率为0.45%～1.93%,能够维持较好的液膜稳定性。研究结果对磷酸中的微量稀土镧回收利用具有一定的参考价值。     

Extraction of Cr (VI) by pickering emulsion liquid membrane using amphiphilic silica nanowires (ASNWs) as a surfactant

Pickering emulsion is the replacement of surfactants with solid, often nano-sized particles. The particle-stabilized emulsions have good thermodynamic and kinetic stability. Pickering emulsion liquid membrane (PELM) was prepared using mahua oil as a diluent, aliquat 336 (Trioctyl methylammonium chloride) as a carrier and amphiphilic silica nanowires (ASNWs) (10–40?ml ethanol addition) as a surfactant. Sodium hydroxide (NaOH) was used as stripping phase in the concentration range from 0.1 to 0.5?M for the extraction of hexavalent chromium [Cr (VI)] from aqueous solution. The variety of edible and non-edible oils was investigated for the stability of water in oil emulsion. Factors that influence silica-stabilized Pickering emulsions are pH, agitation speed, stripping phase concentration, the volume ratio of membrane to stripping phase (M/S), initial feed concentration, treat ratio(feed to emulsion volume ratio) and surfactant concentration for better PELM stability. And also, the extraction efficiency of Cr (VI) was investigated using aliquat as a carrier. The physicochemical properties of ASNWs were studied using Scanning Electron Microscopy (SEM), Fourier Transforms Infrared Spectroscopy (FTIR) and Dynamic Light Scattering (DLS) techniques. At an optimum condition, 99.69% of Cr (VI) removal from aqueous solution was obtained.     

Steric stabilization of thermally responsive N-isopropylacrylamide particles by poly(vinyl alcohol)

Poly(vinyl alcohol) (PVA) was used as a steric stabilizer for the dispersion polymerization of cross-linked poly(N-isopropylacrylamide) (PNIPAM) in water. A series of reactions were carried out using PVA of varying molecular weight and degree of hydrolysis. Under appropriate conditions, PNIPAM particles of uniform and controllable size were produced using PVA as the stabilizer. The colloidal stability was investigated by measuring changes in particle size with temperature in aqueous suspensions of varying ionic strength. For comparison, parallel colloidal stability measurements were conducted on PNIPAM particles synthesized with low-molecular-weight ionic surfactants. PVA provides colloidal stability over a wide range of temperature and ionic strength, whereas particles produced with ionic surfactants flocculate in moderate ionic strength solutions upon collapse of the hydrogel as the temperature is increased. Experimental results and theoretical consideration indicate that sterically stabilized PNIPAM particles resulted from the grafting of PVA to the PNIPAM particle surface. The enhanced colloidal stability afforded by PVA allows the temperature-responsive PNIPAM particles to be used under physiological conditions where electrostatic stability is ineffective.     

Study on the oscillating phenomena of electrical potential across a liquid membrane

The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustained and rhythmic oscillation was observed. To a certain extent, the features of the oscillation (e.g. induction time, frequency, life time and orientation of the pulse pikes) strongly depend on the property of surfactant, dissolved in octanol. The mechanism may be explained by the formation and destruction of dual-ion surfactant membrane accompanying with emulsification at the interface and considering the coupling effect of diffusion and associated reaction in the vicinity of the interface.     

Emulsion stability and potassium leakage in emulsion liquid membrane systems

Potassium leakage was studied in liquid membrane systems containing various emulsifiers and compared with emulsion, stability in the storage test. The effects of various parameters upon emulsion stability and the leakage of standard traces are discussed. The transfer of cations can be caused by emulsion breaking, by transport with the specific carrier and/or with surfactants used as emulsifiers. The latter case becomes especially important when hydrophilic surfactants, e.g. ones containing polyoxyethylene chains, are present in liquid membranes. In systems containing hydrophobic emulsifiers the transfer of potassium is relatively low. In each case considered the effect of emulsifiers upon the transfer of the standard tracer should be checked prior to using the leakage test to characterize emulsion stability.     

Development of radioligands for the dopamine transporter

The extraction of Penicillin G (Pen G) and its conversion to 6-aminopenicillin acid (6-APA) and phenylacetic acid (PAA) was performed by means of Penicillin G Amidase immobilised in the emulsion liquid membranes. Using various surfactants as emulsifiers and an appropriate carrier it is possible to obtain different extraction rates of Pen G as well as back transfer rates of the hydrolysis products. The surfactants with polyoxyethylene chain facilitate the back transfer through the membrane phase, whereas the more hydrophobic surfactants, e.g., Paranox 100, tend to accumulate Pen G hydrolysis products in the internal aqueous phase.     

Responsive Aqueous Foams

Remarkable properties have emerged recently for aqueous foams, including ultrastability and responsiveness. Responsive aqueous foams refer to foams for which the stability can be switched between stable and unstable states with a change in environment or with external stimuli. Responsive foams have been obtained from various foam stabilizers, such as surfactants, proteins, polymers, and particles, and with various stimuli. Different strategies have been developed to design this type of soft material. We briefly review the two main approaches used to obtain responsive foams. The first approach is based on the responsiveness of the interfacial layer surrounding the gas bubbles, which leads to responsive foams. The second approach is based on modifications that occur in the aqueous phase inside the foam liquid channels to tune the foam stability. We will highlight the most sophisticated approaches, which use light, temperature, and magnetic fields and lead to switchable foam stability.     

Water-in-water emulsions stabilized by non-amphiphilic interactions: polymer-dispersed lyotropic liquid crystals

Emulsion systems involving surfactants are mainly driven by the separation of the hydrophobic interactions of the aliphatic chains from the hydrophilic interactions of amphiphilic molecules in water. In this study, we report an emulsion system that does not include amphiphilic molecules but molecules with functional groups that are completely solvated in water. These functional groups give rise to molecular interactions including hydrogen bonding, pi stacking, and salt bridging and are segregated into a dispersion of droplets forming a water-in-water emulsion. This water-in-water emulsion consists of dispersing droplets of a water-solvated biocompatible liquid crystal--disodium cromoglycate (DSCG)--in a continuous aqueous solution containing specific classes of water-soluble polymers. Whereas aqueous solutions of polyols support the formation of emulsions of spherical droplets consisting of lyotropic liquid crystal DSCG with long-term stability (for at least 30 days), aqueous solutions of polyamides afford droplets of DSCG in the shape of prolate ellipsoids that are stable for only 2 days. The DSCG liquid crystal in spherical droplets assumes a radial configuration in which the optical axis of the liquid crystal aligns perpendicular to the surface of the droplets but assumes a tangential configuration in prolate ellipsoids in which the optical axis of the liquid crystal aligns parallel to the surface of the droplet. Other classes of water-soluble polymers including polyethers, polycations, and polyanions do not afford a stable emulsion of DSCG droplets. Both the occurrence and the stability of this unique emulsion system can be rationalized on the basis of the functional groups of the polymer. The different configurations of the liquid crystal (DSCG) droplets were also found to correlate with the strength of the hydrogen bonding that can be formed by the functional groups on the polymer.