异丁醇-水-硝基乙烷体系中的双因素自耦合界面不稳定现象

指导了发生在异丁醇、硝基乙烷和水三组分两相体系中的多因素复合界面不稳定现象，文中通过对一个滴加在异丁醇水溶液表面的硝基乙烷液滴的运动特征的分析，揭示了该现象的规律，在体系趋于热力学平衡的过程中，硝基乙烷液滴先表现出周期性的振荡运动，然后转变为螺旋线和圆周运动，提出了一个溶质迁移和相间溶解的双因素自耦合机理，认为该现象的根本起因是表面活性剂溶质相间迁移所导致的溶质Ｍａｒａｎｇｎｉ效应，但由于丁醇的相     

界面振荡现象

表面活性剂十二烷基三甲基溴化铵从水相向硝基乙烷相的迁移导致以界面振荡为特征的界面不稳定现象，基于界面吸附平衡对该现象的成因进行解析，得到了体现溶质界面吸附和扩散迁移的双因素关系式，可对界面振荡运动的成因及有关规律作出解释。     

界面现象与液滴聚并

报导了一个受溶质Marangoni效应影响的液滴聚结的迟缓现象．采用示踪液滴法，对滴加在正戊醇水溶液表面、受自发界而流控制的硝基乙烷液滴的运动和存在状态进行了研究．结果显示，在一定体系中溶质Marangoni效应可导致液滴的悬浮态，并对液滴的聚并产生显著影响．由于界面状态的不同，示踪液滴也表现出完全不同的动力学特征．基于以上认识对液滴运动速率的计算得到了合理的结果．     

界面不稳定现象研究

界面不稳定现象研究胡学铮张景尧虞学俊（无锡轻工大学化学工程系２１４０３６）液－液或气－液体系中的溶解、蒸发，表面活性物质的迁移和温度效应可能导致自发的界面变形、界面流和界面运动，该现象是界面局部区域物理化学和流体动力学过程的综合表现，称为Ｍａｒａｎｇ...     

OCS表面活性剂在弱碱、无碱条件下的界面张力性能研究

研究了OCS表面活性剂中试产品在弱碱NaCO33及无碱条件下应用于不同油田原油的油-水界面张力特性。结果表明：对于大庆采油四厂原油，当表活剂浓度为0．1％-0．3％，Na2CO3浓度为0．6％-1．2％时，油-水界面张力可达到超低(-l0^-3mN／m数量级)；对于大庆采油二厂原油，当表面活性剂浓度为0．1％-0．3％，Na2CO3浓度为0．8％-1．4％时，油-水界面张力可达到超低；对于华北油田古-联原油，当表面活性剂浓度为0．2％，NaCO3浓度为0．6％-1．2％时，油-水界面张力可达到超低；对于胜利油田孤东采油厂原油，当表面活性剂浓度为0．2％，NaCO3浓度为0．8％-1．4％时，油-水界面张力可达到超低。在无碱条件下，对于大港油田枣园1256断块原油，当OCS表面活性剂浓度达到0．1％时，油-水界面张力即可达到超低；对于江苏油田原油，当OCS表面活性剂浓度在0．1％以上时，油-水界面张力均可以达到10^-2mN／m数量级。聚丙烯酰胺聚合物的加入对油-水超低界面张力的形成和稳定具有促进作用。     

新铜试剂推动稀土离子La（Ⅲ）在液／液界面迁移的伏安行为研究

用循环伏安法研究了中性载体新铜试剂（Ｌ）络合推动稀土离子Ｌａ（Ⅲ）在水／硝基苯界面迁移的伏安行为，结果证实ＬａＣｌ３在水溶液中水解成Ｌａ（ＯＨ）＾２＋（ｍ＾２＋），其迁移过程可表达为：Ｍ＾２＋（ｗ）＋ＳＬ（ｎｂ＝ＭＬｓ＾２＋（ｎｂ）．     

色谱柱分离过程弛豫理论——流出曲线的动力学本质

在分析型线性色谱中,流出曲线一般表现为拖尾的形式,这种现象可以采用多种机理加以解释。模仿动力学弛豫理论的假设条件,认为溶质在柱过程中的迁移以跃迁形式完成,得到了浓度分布曲线的数学表达式。分别探讨跃迁次数、两相间跃迁速率及溶质在流动相中的轴向跃迁对峰形的影响,进一步说明了色谱流出曲线的动力学本质     

物理界面界面层模型润湿理论

本文依据物理界面界面层模型讨论了润湿现象, 提出以润湿系数表示相间润湿能力, 研究了润湿系数的计算方法, 讨论了Young方程和物理界面界面层模型润湿计算公式的正确性, 并以实验数据验证了润湿系数计算值。     

用SEC柱和胶束流动相分离小分子的模型

 使用体积排阻色谱 (SEC)柱和胶束流动相成功地分离了一些小分子化合物 ,给出了分离模型。这种分离方式是基于胶束和水相在色谱过程中的不同迁移以及溶质在胶束和水相间的不同分配而实现的 ,其分离的机制与胶束电动色谱 (micellar electrokinetic chromatography,MEKC)十分相似。理论处理的结果表明 ,溶质的保留体积与胶束浓度有关 ;通过溶质的保留体积可得到溶质在胶束和水相间的分配系数。还采用了两种不同的 SEC柱分离了一些脂肪醇 ,验证了这一理论模型 ,测定了它们的分配系数 ,结果表明两种柱测得的小分子醇在胶束和水相中的分配系数具有较好的一致。     

钐离子在油／水界面迁移的电化学行为

钐离子在油／水界面迁移的电化学行为①狄俊伟＊徐肖邢＊＊吴莹范瑞溪（苏州大学化学化工学院苏州２１５００６）近年来，人们对中性载体推动金属离子在油／水界面转移的报道较多［１～４］．通常的实验研究大多采用水相中的金属离子ＭＺ＋大大过量，而于油相中溶解少量的...     

界面不稳定现象与相间迁移

The interfacial instability due to the transfer of the 1-butanol from water to oil in two systems of 1-butanol oil/water has been studied. The dynamic characteristics of the phenomenon are investigated by analysing the motion of an oil lens deposited at the surface of the aqueous solution of 1-butanol. The interfacial adsorption kinetics based on diffusion-controlled transfer is analysed. It is found that the linear relation between the frequence of the oscillatory motion of the lens and t1/2 is a characteristic relation. The type of the solute transfer in the interfacial instability is discussed by comparing experimental results with the linear characteristics.     

Solutal Marangoni effect : I. Pure interfacial transfer

The motion of a nitroethane lens located at the surface of an aqueous solution of dodecyltrimethylammonium bromide is analyzed. This motion is generated by a solutal Marangoni effect, or soluto—capillary instability, induced by the transfer of the surfactant from one phase to the second one, both solvents being mutually saturated; its quasi-periodic character is demonstrated by a statistical and spectral analysis, and its characteristics, amplitude, and frequency are discussed as a function of the physicochemical conditions. The enhancement of the interfacial transfer by the Marangoni effect is evaluated. It is shown that none of the available models of linear stability analysis can account for the present results.     

Middle-phase microemulsions of green surfactant alkyl polyglucosides

Microemulsions are important organized molecular assembles in surfactant solutions and are used in various fields such as tertiary oil recovery, pharmaceutics, cosmetics, nanoparticle synthe-sis and chemical engineering. The more commonly used nonionic surfactants to produce micro- emulsions are the ethylene oxide-based compounds (CiEj). In recent years alkyl polyglucosides have been received considerable attention in producing microemulsions[17]. Alkyl polyglucosides (APG), which are widely…     

Electrochemical instability in the transfer of cationic surfactant across the 1,2-dichloroethane/water interface

The electrochemical instability has been shown to appear in the transfer of cationic surfactant ions across the 1,2-dichloroethane/water interface. Cyclic voltammograms possess all fundamental characteristics that are predicted by the theory of electrochemical instability: the presence of the instability window, that is, the potential range where the interface becomes unstable, the location of the instability window around the standard ion transfer potential of surface-active ions, and the dependence of the width of the instability window on the concentration of the surfactant ions. Electrocapillary measurements clearly demonstrate that the interface becomes unstable, while the interfacial tension is positive, being higher than 20 mN m(-1). The electrocapillary curve exhibits the discontinuities at both ends of the instability window, indicating the similarity between the electrochemical instability and the phase transitions induced by the temperature, pressure, and chemical potential. The results from voltammetry and interfacial tension measurements for cationic surfactants support the idea that the electrochemical instability, so far reported in the transfer of anionic surfactants across the liquid/liquid interface, is one of intrinsic properties of the two-phase systems where the partition of surface-active ions takes place.     

Scanning electrochemical microscopy (SECM) studies of oxygen transfer across phospholipid monolayers under surface pressure control: comparison of monolayers at air/water and oil/water interfaces

Scanning electrochemical microscopy has been used in combination with a specially designed Langmuir trough to compare the kinetics of oxygen transfer across an L-alpha-phosphatidylethanolamine, distearoyl monolayer spread at three different interfaces: air/water, air/water in contact with an oil lens, and oil/water. The monolayer is shown to reduce the kinetics of interfacial transport, and rate constants for the transport of oxygen across each interface, at different surface pressures, have been evaluated. The results obtained for each interface are compared, and the implications for studies of passive diffusion across cell membranes are discussed.     

Water-in-crude oil emulsions from the Norwegian continental shelf

A destabilization study of water-in-crude oil emulsions based on crude oils from the Norwegian Continental Shelf is reported. It is found that medium-chain alcohols (1-butanol and benzyl alcohol) and amines are speeding up the separation of water. The destabilization mechanisms in these two cases seem to be fundamentally different. The alcohols seem to modify the rigidity of the interfacial film by a diffusion/partitioning process while the amines show a strong and specific interaction with interfacial groups, hence hydrophilizing the whole film. Observed trends in the time-dependence of the interfacial tension upon addition of alcohols and amines support these suggestions to destabilization mechanisms. Data for a commercial demulsifier Dissolvan 4455 are also given.     

Spontaneous periodic pulsation of contact line in oil/water system--frequency control with divalent cations and applied voltage

Periodic oscillatory change of hydrophilicity (or hydrophobicity) of a glass surface was studied. A glass capillary was immersed normally at an oil/water interface. The water phase contained the cationic surfactant trimethyloctadecylammoniumchloride, and the oil phase contained bis(2ethylhexyl) phosphate. Adsorption of the surfactant molecules and their desorption via anionic chemicals dissolved in the oil generated a gradual wetting by the water, followed by a rapid wetting by oil. The three phase contact line exhibited a pulse-like motion that continued, at least for a few minutes. The frequency depended on the cation species dissolved in water and the applied voltage across the oil/water interface. Four kinds of cations, Mg(2+), Ca(2+), Sr(2+) and Ba(2+) were used. While the frequency order was Ba(2+)>Sr(2+)>Mg(2+), the Ca(2+)-containing interface did not show any motion irrespective of the applied voltage. There was a threshold voltage and concentration of anionic chemical that was necessary for the onset of this motion. The pulsation mechanism and its ion selectivity are also discussed. This interfacial motion was a typical nonlinear oscillation with an ion-selective nature. In this regard, this interfacial motion had biomimetic characteristics.     

Electrochemical Behavior of Anthraquinone in Reverse Micelles and Microemulsions of Cetyltrimethylammonium Bromide

The electrochemical behavior of an anthraquinone (AQ) was studied in aqueous solutions at a glassy carbon electrode, using the sodium salt of anthraquinone-2-sulfonic acid (AQS), by employing cyclic voltammetry. AQ undergoes a two-electron reduction in aqueous media. The electrochemical behavior of AQ was also investigated in micelles, reverse micelles (CTAB/1-butanol/water), and microemulsions (CTAB/1-butanol/water/cyclohexane) of cetyltrimethylammonium bromide (CTAB). The electrode reactions of AQ in reverse micelles and microemulsions are nearly reversible at low oil (cyclohexane) content. However, at higher oil content, the reversibility is gradually lost. In the case of reverse micelles, the reduction current, as well as the reduction potential, of AQ depend on the transition from a micellar solution to a stable solution of reverse micelles that occurs with added 1-butanol. In microemulsions, the change in cyclohexane content was found to cause a linear increase in the peak current for AQ reduction as well as a linear decrease in the corresponding reduction potential. As the cyclohexane content is increased, the o/w microemulsions dominated by micelles undergo a transition to a w/o microemulsion dominated by reverse micelles, which causes changes in the electrochemical behavior.     

Channel shape effects on the solution-flow characteristics and the liquid/liquid extraction efficiency in polymer microchannel chips.

A polymer microchannel chip with a symmetrical or unsymmetrical zigzag-side-walled structure was fabricated by an imprinting method, and applied to study shape effects on solution flow characteristics as well as on the liquid/liquid extraction efficiency of an aluminium(III) chelate complex (Al-DHAB: DHAB = o,o'-dihydroxyazobenzene) in a microchannel chip. In an unsymmetrical zigzag-side-walled channel chip (us-channel), an oil/water interface was sinusoidal, while that in a symmetrical zigzag-side-walled channel chip (s-channel) was flat as long as the observation was made under an optical microscope. It was demonstrated that the efficiency of the water-to-oil (1-butanol) extraction of Al-DHAB in the microchannel was governed by the contact time between the two phases. As the most important results, furthermore, the extraction efficiency was higher in the us-channel, as compared with that in the s-channel, owing to the sinusoidal liquid/liquid interfacial structure and, therefore, to the high interfacial area between the two phases.