辛基三甲基溴化铵与辛基硫酸钠混合水溶液的相行为

对辛基三甲基溴化铵(OTAB)与辛基硫酸钠(SOS)正、负离子混合表面活性剂水溶液的相行为进行了研究.在高浓度的溶液中,混合表面活性剂形成液晶相,随着混合摩尔比OTAB/SOS接近于1,液晶结构由六角相转层状相,同时夹杂少量沉淀物;在中等浓度时,任意混合摩尔比例下皆为均相透明溶液;在低浓度下,在很宽的OTAB/SOS混合摩尔比的范围,出现双水相,其中的表面活性剂稀薄相,为不同大小的胶团与囊泡组成的稀溶液,另一表面活性剂富集相中则为数密度很大的囊泡聚集体,富集相对油溶性染料的增溶作用比非富集相高得多.     

盐引发阴离子/非离子表面活性剂复配体系中囊泡自发形成

在无盐时, 阴离子表面活性剂十二烷基苯磺酸钠(SDBS)与非离子表面活性剂壬基酚聚氧乙烯(10)醚(TX-100)的复配体系中只有混合胶束存在, 而盐的加入即可以引发体系中囊泡的自发形成, 这使得囊泡的形成变得更加简单. 引发机理可以归因于盐对离子表面活性剂的极性头双电层的压缩作用, 减少了极性头的面积, 加上非离子表面活性剂的参与使得堆积参数P增加, 导致了半径更大的聚集体的形成. 制作了SDBS/TX-100/盐水拟三元相图, 通过目测和表面张力的变化确定了囊泡形成的带状区域, 并用负染色电镜(TEM)对囊泡进行了表征, 同时测定了盐度以及相同盐度下表面活性剂浓度对囊泡粒径的影响, 发现囊泡的粒径随着盐度的增加而增加, 而在同一盐度下, 囊泡的粒径基本不受表面活性剂浓度的影响.     

十四烷基三甲基氯化铵/十二烷基苯磺酸钠混合表面活性剂双水相体系的萃取性能

研究了十四烷基三甲基氯化铵(TTAC)与十二烷基苯磺酸钠(SDBS)混合表面活性剂水溶液双水相体系的分相情况、萃取性能及两相的微观结构.结果表明,TTAC/SDBS混合表面活性剂水溶液在30℃下能够形成稳定的双水相体系;该双水相体系对亚甲基蓝、靛红都具有一定的萃取分离作用.其上、下两相的微观结构明显不同,这是其能够形成稳定双水相体系且具有萃取作用的重要原因.     

表面活性剂混合物水溶液中的囊泡形成

1:1烷基羧酸钠-溴化烷基三甲铵混合水溶液的浓度在cmc以上时, 能自发或超声分散形成一类新型混合表面活性剂囊泡(单层膜), 正负离子表面活性剂的突出囊泡形成能力以及不同表面活性剂结构组合变化所显现的多样特性, 皆预示出混合功能有序组合体研究的广阔前景。     

类水滑石诱导囊泡的自发形成

报道了一种新的囊泡合成方法——荷电固体纳米颗粒诱导囊泡的自发形成. 研究发现, 将5.0 g/L带结构正电荷的Mg₃Al类水滑石(HTlc)溶胶和0.02 mol/L由两性表面活性剂十二烷基甜菜碱(C₁₂BE)和阴离子表面活性剂双(2-乙基己基)琥珀酸磺酸钠(AOT)组成的溶液(C₁₂BE与AOT物质的量比为3∶2)混合, 当HTlc溶胶与表面活性剂溶液的体积比在1∶9～4∶6范围内, 在HTlc纳米颗粒的诱导下可自发形成囊泡, 并获得稳定的HTlc-囊泡复合分散体系.     

pH及有机小分子物质对SDS/CTAB/H2O系统双水相性质的影响

正离子表面活性剂与负离子表面活性剂混合物能产生比单一表面活性剂更高的表面活性[1 ] 。在适当条件下 ,正负离子表面活性剂的水溶液能产生两个互不相溶的水相 ,即表面活性剂双水相系统[2 ] (ＡｑｕｅｏｕｓＴｗｏ -ＰｈａｓｅＳｙｓｔｅｍ -ＡＴＰＳ)。作者曾指出双水相上相为液晶 (ＬｉｑｕｉｄＣｒｙｓｔａｌ -ＬＣ)结构 ,下相为各向同性溶液 ,盐离子通过改变双水相中表面活性剂有序组合体的反离子层的状态而对双水相的组成、结构等产生重要的影响[3,4] 。本文进一步研究ｐＨ及有机小分子物质在十二烷基硫酸钠 /十六烷基三甲基溴化铵 /…     

蛋白质在表面活性剂与高分子共组双水相体系中 的分配

高分子和正负离子表面活性剂混合物可形成一种新型双水相体系。研究蛋白质在溴化十二烷基三乙铵/十二烷基硫酸钠与聚氧乙烯(EO)-聚氧丙烯(PO)嵌段共聚物(EO~2~0PO~8~0)共组双水相体系中的分配。通过在高分子接上亲和配基,研究蛋白质在带有亲和配基高分子的双水相体系中的分配。将表面活性剂富集相稀释或加热高分子富集相,又可形成新的双水相体系,由此可进行蛋白质的多步分配。在蛋白质的分配完成之后,通过将表面活性剂富集相进一步稀释或将高分子富集相加热至高分子浊点以上可将表面活性剂和高分子与目标蛋白质分离。正负离子表面活性剂和高分子还可以循环使用。     

N-烷基-N-(2-羟乙基)-N,N-二甲基溴化铵与十二烷基硫酸钠复配系统的双水相

合成了N-十二烷基-N-(2-羟乙基)-N,N-二甲基溴化铵、N-十四烷基-N-(2-羟乙基)-N,N-二甲基溴化铵和N-十六烷基-N-(2-羟乙基)-N,N-二甲基溴化铵等3个季铵盐阳离子表面活性剂. 研究了它们以及N-十六烷基-N,N,N-三甲基溴化铵(CTAB)与阴离子表面活性剂十二烷基硫酸钠(SDS)复配系统在313.15 K时的双水相行为. 复配系统在两个非常狭窄的区域能形成双水相, 两相区近似以等摩尔线为中心对称分布, 随着阳离子表面活性剂碳链长度的增长, 富含阳离子表面活性剂的双水相区向阴阳离子表面活性剂摩尔比减小的方向稍有移动.     

环境因素对正负表面活性剂体系相行为的影响

在1:1正负离子表面活性剂混合体系(十二烷基硫酸钠/辛基三甲基溴化铵 SDS-C8NM3Br; 十二烷基硫酸钠/十二烷基三甲基溴化铵,SDS-C12NM3Br)中加入短链脂肪醇 (乙醇,正丙醇,正丁醇),正负离子表面活性剂沉淀溶解,出现表面活性剂双水相.上相有液晶存在,下相有囊泡自发形成.折光率数据和电镜结果表明:上相为表面活性剂富集相,下相表面活性剂浓度较低.混合体系中,出现表面活性剂双水相所需短链脂肪醇的体积百分数,随短链脂肪醇的链长增加而降低.温度升高,出现表面活性剂双水相所需短链脂肪醇的体积百分数降低.对SDS/C8NM3Br/H2O体系的研究结果表明:超声处理,可使混合体系中沉淀向囊泡转化,与短链脂肪醇的加入后的作用类似.     

正负离子表面活性剂与高聚物混合双水相体系的相行为及蛋白质的分配

报道了由正负离子表面活性剂与高聚物混合溶液形成的一种可用于蛋白质的分离及分析的新型双水相萃取体系.研究了正负离子表面活性剂(溴化十二烷基三乙铵/十二烷基硫酸钠)分别与葡聚糖和聚乙二醇混合双水相体系的形成规律、相行为及牛血清蛋白和溶菌酶在双水相体系中的分配.通过在高聚物分子中接上亲和配基,研究蛋白质在双水相体系中的亲和分配.结果表明,在该体系中,表面活性剂与高聚物分别富集于不同相中.升高温度及加入无机盐均可促进双水相体系的形成,不同蛋白质可分配于不同的相中.亲和配基的引入极大地增强了蛋白质分配的选择性.     

表面活性剂双水相的性质及其应用 Ⅰ. 表面活性剂双水相的微环境性质

阴、阳离子表面活性剂混合体系, 在一定浓度及混合比范围内, 可以形成两个互不相溶、平衡共存的水相, 称为表面活性剂双水相。其中阳离子表面活性剂过量的双水相体系, 称为阳离子双水相。本文分别以芘和罗丹明B作为探针, 用荧光探针法研究了摩尔比为1.6:1的C12NE和SDS混合体系成形成的阳离子双水相,测定其上层和下层的胶束微环境的极性和微粘度, 取得了有意义的结果。     

Limonene in Arizona liquid systems used in countercurrent chromatography. II Polarity and stationary-phase retention

The previous article in this series described the physico-chemical properties and chemical compositions of the two phases of the limonene–ethyl acetate–ethanol–water biphasic liquid system. This system was designed to be a “green” version of the so-called Arizona (AZ) scale of heptane–ethyl acetate–methanol compositions in which the heptane–ethyl acetate volume ratio is exactly the same as the methanol–water ratio. The first major difference between the standard and “green” AZ systems is the difference in upper and lower phase densities. The higher density of limonene compared with heptane greatly reduces the density difference of the “green” system: half the compositions have a density difference lower than 0.06 g mL^?1, precluding their use in hydrodynamic CCC columns. The other major difference is the phase polarity. The better distribution of ethanol between the upper organic and lower aqueous phases of the “green” AZ scale renders them more polar than their counterparts in standard heptane-based compositions. The test solutes aspirin and coumarin have higher distribution constants in the “green” AZ compositions. It is revealed that a hydrostatic column is suitable for use with all “green” compositions, with very good phase retention and limited driving pressure at high flow rates. A hydrodynamic column only functioned at limited flow rates with polar compositions of sufficient phase-density difference. The CCC chromatograms obtained with different compositions and columns are shown, and their peak position and sharpness discussed.     

Adsorption, association and precipitation in hexadecyltrimethylammonium bromide/sodium dodecyl sulfate mixtures

The phase equilibria of surfactant aqueous mixtures, hexadecyltrimethylammonium bromide and sodium dodecyl sulfate, have been studied by polarizing microscopy, quasielastic light scattering, conductivity, potentiometric, electrophoretic, and surface tension measurements. Adsorption at the air/solution interface, association and precipitation in bulk solution strongly depended on the molar ratio and the concentration of surfactants. Catanionic vesicles coexisted with crystalline catanionic salts in a broad concentration range. The relative proportions of crystallites and vesicles varied according to the concentration and the molar ratio of the surfactants. The solid crystalline phase was progressively converted to catanionic vesicles with increasing surfactant molar ratio. At the highest excess of one of the surfactants transition from catanionic vesicles to mixed micelles occurred. The formation and stability of different phases are discussed in terms of surfactant molecular packing constraints and electrostatic interactions in the headgroup region. Surfactant tail-length asymmetry and the change of electrostatic interactions in the headgroup region from attractive to repulsive are governing factors for the transition from planar to curved bilayers. Received: 9 June 1998 Accepted: 18 August 1998     

DTAB-月桂酸钠体系表面活性剂双水相研究

绘制和分析了十二烷基三甲基溴化铵（DTAB） 月桂酸钠（SL）组成的表面活性剂混合体系相图,系统研究了温度和无机盐等因素对该体系表面活性剂双水相 (ASTP) 影响的规律性.结果表明:与富含负离子表面活性剂双水相 (ASTP A) 相比较,富含正离子表面活性剂双水相(ASTP C)区域更大、更稳定;温度升高,无机盐(NaBr)的浓度增大,都引起 ASTP 体系上相体积的减小和下相体积的增加;囊泡普遍存在于ASTP的上下相之中.     

Aqueous Two‐Phase System (ATPS) Containing Gemini (12‐3‐12,2Br−) and SDS I: Phase Diagram and Properties of ATPS

Two phases coexist in an aqueous system that contains the two surfactants cationic gemini 12‐3‐12,2Br? and anionic SDS. An aqueous two‐phase system (ATPS) is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic‐anionic surfactant systems. In that region, the molar ratio of gemini to SDS varies with the total concentration of surfactants. ATPS not only has higher stability but also has longer phase separation time for the new systems than that of the traditional system. Furthermore, the optical properties of ATPS are different at different total concentrations. All of these experimental observations can be attributed to the unique properties of gemini surfactant and the synergy between the cationic gemini surfactant and the anionic surfactant SDS.     

两相催化体系中双子表面活性剂对1-十二烯氢甲酰化反应的助催化作用

合成了几种具有刚性连接基团的双子表面活性剂,研究了它们在Rh-TPPTS体系中催化长链烯烃氢甲酰化反应中的助催化作用.结果表明,在水/有机两相催化体系中,新型双子表面活性剂的助催化作用比单链表面活性剂CTAB更好,在较低的表面活性剂浓度下能得到较高的反应转化率.这归因于此类表面活性剂有较低的cmc,降低界面张力的能力和对1-十二烯的增溶能力比CTAB更强.     

Electron microscopic and light scattering observation on a system with two iridescent phases

Electron microscopic observations and classical light-scattering measurements have been carried out for dodecyldimethylaminoxide/hexanol/water mixtures in the concentration range where iridescent colors occur. This system has two different iridescent phases. The iridescent phase with more hexanol forms quickly, and the phase with less hexanol forms very slowly. Three different isotropic phases which show strong flow birefringence are found near both iridescent phases. The electron microscopic pictures show clearly that only one of these isotropic phases with strong flow birefringence is a bicontinuous sponge phase (L_3h -phase). This is the phase which comes out by adding some alkanol to the upper lamellar phase. The flow birefringent phase below the lower lamellar phase forms unilamellar vesicles. The flow birefringent phase which occurs between both iridescent phases contains multilamellar vesicles and is shown to be a precursor of a lamellar phase.     

正负离子表面活性剂/离子液体双水相性质研究

本文把短链离子液体(IL)四氟硼酸1-乙基-3-甲基咪唑鎓[C2mim]BF4引入正负离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)双水相体系(SDS/DTAB/H2O)中,研究了IL对双水相相图及相分离体系性质的影响。结果表明,[C2mim]BF4的阳离子性质是影响阴离子表面活性剂过量区域性质的主要因素,IL通过静电作用、氢键作用等改变体系中聚集体的形貌,最终导致阴离子双水相(ATPSa)的消失。IL的阴离子对阳离子双水相(ATPSc)区域性质起着决定作用;IL的盐效应引起的对表面活性剂混合胶束扩散双电层的压缩作用,不但促进胶团的形成,缩短了形成稳定胶团所需要的时间,加快了双水相的相分离速度,而且也造成了形成ATPSc所需DTAB含量的提高。IL的引入改变了ATPSc上、下相表面活性剂的组成及含量,使富含表面活性剂的上相中阳离子表面活性剂含量更高,进而提高了双水相的萃取性能,其上相对甲基橙的萃取效率可高达96.67%。