Phase Behavior in Mixtures of Cationic Dimeric and Anionic Monomeric Surfactants

The formation of mixed aggregates has been investigated in the mixture of oppositely charged surfactants vastly differing in molecular geometry and size. The systems considered is mixture of the cationic gemini surfactant, ethanediyl-1,2-bis(dodecyldimethylammonium bromide), and anionic surfactant, sodium dodecyl sulfate. Various mixed nano- and microaggregates (micelles, vesicles, thin lamellar sheets, and tubules) were formed depending on bulk composition and total surfactant concentration. Two types of aggregates were found in precipitate, the tubules as prevailing aggregates on the gemini-rich side, and vesicles as prevailing aggregates on the SDS-rich side. The tubules formation was ascribed to mutual influence of specific structure of cationic dimeric surfactant and electrostatic interactions at the bilayer/solution interface. The proposed mechanism involved the formation of lamellar sheets, which rolled-up into tubules.     

正离子Gemini表面活性剂/负离子聚电解质相互作用的研究

摘要 采用荧光探针法和电导法研究了正离子偶联表面活性剂(C₁₂H₂₅(CH₃)₂N-(CH₂)₆-N(CH₃)₂C₁₂H₂₅•2Br) (12-6-12• 2Br^－)和带相反电荷聚电解质聚丙烯酸钠(NaPA)的相互作用, 结果表明: 由于静电相互作用, 12-6-12•2Br^－和NaPA之间可以形成类胶束或复合物. 对比十二烷基三甲基溴化铵(DTMAB)与NaPA复配体系的荧光光谱, 发现偶联表面活性剂与NaPA的相互作用强于传统表面活性剂. 此外, 还研究了盐和醇对偶联表面活性剂/聚丙烯酸钠的复配体系微极性的影响, 发现盐和醇对表面活性剂在聚电解质上形成类胶束和复合物的溶解都有一定的促进作用.     

Mixing Behavior of Conventional and Gemini Cationic Surfactants

Micellization behavior of cationic monomeric surfactants, hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium bromide (CPB), cetylpyridinium chloride (CPC), tetradecyltrimethylammonium bromide (TTAB), and dimeric (gemini) cationic surfactant pentamethylene‐1, 5‐bis(hexadecyldimethylammonium bromide) with formula C₁₆H₃₃(CH₃)₂N⁺(CH₂)₅N⁺(CH₃)₂C₁₆H₃₃ · 2Br^?, abbreviated as 16‐5‐16, in mixed states (binary) have been studied by conductivity. The micellar compositions, activities of the components, and their mutual interactions have been estimated from Rubingh's theory. The mixtures show nonideal behavior with favorable interactions.     

pH-Responsive Rheological Properties and Microstructure Transition in Mixture of Anionic Gemini/Cationic Monomeric Surfactants

Surfactant aggregates have long been considered as a tool to improve drug delivery and have been widely used in medical products. The pH-responsive aggregation behavior in anionic gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C₁₂C₃C₁₂(SO₃)₂) and its mixture with a cationic monomeric surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. The spherical-to-wormlike micelle transition was successfully realized in C₁₂C₃C₁₂(SO₃)₂ through decreasing the pH, while the rheological properties were perfectly enhanced for the formation of wormlike micelles. Especially at 140 mM and pH 6.7, the mixture showed high viscoelasticity, and the maximum of the zero-shear viscosity reached 1530 Pa·s. Acting as a sulfobetaine zwitterionic gemini surfactant, the electrostatic attraction, the hydrogen bond and the short spacer of C₁₂C₃C₁₂(SO₃)₂ molecules were all responsible for the significant micellar growth. Upon adding CTAB, the similar transition could also be realized at a low pH, and the further transformation to branched micelles occurred by adjusting the total concentration. Although the mixtures did not approach the viscosity maximum appearing in the C₁₂C₃C₁₂(SO₃)₂ solution, CTAB addition is more favorable for viscosity enhancement in the wormlike-micelle region. The weakened charges of the headgroups in a catanionic mixed system minimizes the micellar spontaneous curvature and enhances the intermolecular hydrogen-bonding interaction between C₁₂C₃C₁₂(SO₃)₂, facilitating the formation of a viscous solution, which would greatly induce entanglement and even the fusion of wormlike micelles, thus resulting in branched microstructures and a decline of viscosity.     

Steady-state fluorescence investigations of aqueous binary mixtures of myristyl alcohol based bis-sulfosuccinate anionic gemini surfactant and effect of different conventional surfactants therein

The present research work is associated with the fluorescence investigations of binary aqueous mixed surfactants solutions of anionic bis-sulfosuccinate gemini surfactant (BSGSMA_1,8) and three different conventional surfactants—anionic viz. sodium dodecyl sulfate (SDS), cationic viz. cetyl trimethyl ammonium bromide (CTAB), and nonionic surfactant viz. Triton X 100. Steady-state fluorescence spectroscopy technique has been utilized to examine the micellization behavior of aqueous solution of pure myristyl alcohol-based BSGSMA_1,8 having flexible methylene chain [(CH₂)₈] as spacer group. Critical micelle concentration (CMC), aggregation number (N), and micropolarity of pure and mixed surfactants systems were explored during the investigations. The results revealed the best synergism behavior of prepared gemini BSGSMA_1,8 with SDS as compared to CTAB and Triton X 100. The maximum reduction in the value of pyrene intensity ratio (I₁/I₃) was observed for gemini and SDS mixed surfactant solution. On the other hand, the increased I₁/I₃ value of mixed gemini with Triton X 100 exhibited that mixed surfactant system of anionic gemini BSGSMA_1,8 with non-ionic Triton X 100 is not as compact as other mixed surfactant systems. Aggregation number increased and micropolarity decreased with increased concentration of gemini surfactants.     

Effects of Spacer Chain Length and Additives on Solution Properties of Cationic Gemini Surfactant

The critical micelle concentration (CMC) has been determined for the gemini surfactant trimethylene-1,3-bis(dodecyldimethyl ammonium bromide)12-s-12,2Br^?1 by means of electricity conductivity measurements. For the same number of carbon atoms in the hydrophobic chain per hydrophilic head group, geminis have CMC values well below those of conventional single-chain cationic surfactants. The CMC of 12-3-12 reduces with the addition of n-alcohol except ethanol and with the increase of n-alcohol chain length as well as increase of concentration of n-butanol and sodium chloride. Steady-state fluorescence quenching technology has been employed to study the aggregation number of micelle, which increases with increase in the length of n-alcohol. The Kraft temperature measurements also indicate that the stability of solid surfactant hydrate decreases along with the improvement of concentration of n-butanol and sodium chloride.     

阳、阴、非离子表面活性剂胶束对酯碱性水解的影响

应用紫外分光光度法和热动力学方法研究了芳香酸酯和正脂肪酸酯在表面活性剂ＤＴＡＢ、ＴＴＡＢ、ＣＴＡＢ、ＳＤＳ、Ｂｒｉｊ３５、ＴｒｉｔｏｎＸ－１００胶束中的碱性水解反应。阳、阴、非离子表面活性剂胶束对酯的碱性水解均有禁阻作用。讨论了胶束对酯碱性水解禁阻作用的原因。     

Prediction on Critical Micelle Concentration of Nonionic Surfactants in Aqueous Solution： Quantitative Structure-Property Relationship Approach

IntroductionCriticalmicelleconcentration (cmc)ofsurfactantsinaqueoussolutionisoneofthemostusefulparametersforcharacterizingthepropertiesofsurfactants.Overaverynarrowconcentrationrangearoundthecmctransitionsoftheexistenceofsurfactantsoccurfrommonomer ,premicel lartomicellar .Andcompanyingthesetransitions ,manyotherimportantpropertiesofsurfactantsolution ,suchassurfacetension ,interfacialtension ,conductivity ,osmoticpressure ,detergency ,emulsification ,foamingandsoon ,alsochangesharplyatthepoi…     

荧光探针法研究新型Gemini表面活性剂在水溶液中的聚集行为

以芘为荧光探针、二苯酮为猝灭剂,用稳态荧光探针法测定了新型Gemini表面活性剂的临界胶团浓度(CMC)、胶团聚集数(N_agg)及胶团微极性.研究了Gemini表面活性剂结构和氯化钠浓度对CMC、N_agg、胶团微极性的影响.结果表明,新型Gemini表面活性剂的CMC比常规表面活性剂的CMC低1—2个数量级.当疏水基碳原子数增加时,CMC依次降低,N_agg增大,胶团微极性减小.当氯化钠浓度增大时,N_agg增大,胶团微极性减小.     

壬基酚聚氧乙烯醚型Gemini季铵盐表面活性剂的合成 及其表面性质的研究

合成了系列壬基酚聚氧乙烯醚型Gemini季铵盐表面活性剂(GNPQA), 用核磁、红外和元素分析对它们的结构进行了表征, 考察了反应条件对转化率的影响, 并用表面张力法和稳态荧光探针法对GNPQA的表面性能及胶束聚集数(N)进行了研究. 结果表明, 较优的反应条件: 反应时间为12 h, 反应温度为70 ℃, 反应原料摩尔比为n(双聚壬基酚聚氧乙烯醚)∶n(三乙胺)∶n(环氧氯丙烷)＝1∶1∶1; GNPQA的临界胶束浓度(CMC)值较相应的单体壬基酚聚氧乙烯醚型季铵盐表面活性剂(NPQA)降低了1～2个数量级, 显示了较高的表面活性; 当GNPQA溶液浓度为5～9倍CMC时, N值随浓度增大而线性增大; 随着氧乙烯(EO)单元数的增长, GNPQA的CMC和N值均逐渐减小; 结合GNPQA的表面性能参数和N值的变化规律, 探讨了这类表面活性剂表面及胶束聚集体的结构形态.     

Salt Effect,Surface, and Aggregation Properties of Binary Surfactant Mixtures of a Nonionic Gemini Surfactant (HBA(EO)80) with Anionic Surfactants

Nonionic gemini surfactants HBA(EO)₈₀ were synthesized and characterized by means of surface tension measurements. CMCs of two mixed system, nonionic gemini mixed with anionic gemini (HBA(EO)₈₀/C11pPHCNa) and nonionic gemini mixed with anionic monomeric (HBA(EO)₈₀/SL) and the effect of salt on the two mixed system were investigated. Freeze-fracture transmission electron microscopy and scanning electron microscopy were used to investigate the mixed aggregates' morphologies. The results show that large spherical aggregates were formed in the mixed solution, which trend to transfer into micelles with the increases of the salt concentration.     

一种新型表面活性剂的表面活性的研究

采用表面张力法确定了新型表面活性剂3-对壬基苯氧基-2-羟丙基三甲基溴化 铵的临界胶束浓度(cmc)，并考察了盐度、温度和pH值对其cmc的影响。结果表明， 此种表面活性剂的表面活性较高，盐度对其cmc影响最大，其次是pH值，温度对其 cmc的影响较为复杂。理论计算结果表明，采用热力学函数可较好地解释试验结果 。     

离子液体型表面活性剂C12mimBr与普通表面活性剂混合性质的研究

研究了离子液体型表面活性剂C12mimBr与阳离子表面活性剂Gemini 12-3-12, DTAB及阴离子表面活性剂SDS复配体系的性质, 并分别采用Rubingh-Margules模型和Rubingh-正规溶液模型计算了临界胶束浓度和混合胶团组成. 研究发现, 两表面活性剂分子结构的匹配性及带电头基之间的相互作用是影响混合溶液性质的主要因素. 对于分子结构差别较大的C12mimBr与Gemini 12-3-12的混合, 其行为远远偏离理想混合性质; 对疏水链长相同仅亲水头基不同的C12mimBr与DTAB则接近于理想混合; 而对C12mimBr＋SDS的复配体系, 正、负电荷间强烈的相互吸引使得混合体系大大偏离理想行为. 计算发现, 两种理论模型得到的混合胶团组成基本一致, 但Rubingh-Margules模型预测的临界胶束浓度比Rubingh-正规溶液模型要好     

Synthesis and Surface Activity of Novel Triazole—based Cationic Gemini Surfactants

Gemini surfactants, which contain two hydrophilic groups and two hydrophobic groups in the molecule, are considered as a new generation of surfactants. These surfactants are about 3 orders of magnitude more efficient at reducing surface tension and more than 2 orders of magnitude more efficient at forming micelles than conventional surfactants1. During recent years, many gemini surfactants have been synthesized, and a considerable number of investigations have been reported on their unusua…     

Gemini 阴离子表面活性剂水溶液的聚集性质

合成了一种Gemini阴离子表面活性剂,测定了其临界胶束浓度cmc和cmc时的表面张力γcmc,与传统的单基表面活性剂相比,其临界胶束浓度降低了一个数量级,具有突出的降低水的表面张力的效率;研究了该种Gemini表面活性剂的浓度对于胶束聚集数的影响,结果表明,随着浓度的增加,胶束聚集数出现了一个极大值,同时观察到液晶微相的生成.     

壬基酚聚氧乙烯醚二聚和三聚表面活性剂的合成及表面性质

合成了系列壬基酚聚氧乙烯醚二聚表面活性剂(DNP)和三聚表面活性剂(TNP), 用核磁共振、红外光谱和元素分析等手段对其结构进行了表征, 并用表面张力法和稳态荧光法对DNP和TNP的表面性能进行了研究. 结果表明, 随着氧乙烯(EO)单元数的增长, DNP和TNP的临界胶束浓度(cmc)值逐渐增大; DNP和TNP的cmc值较相应的单体壬基酚聚氧乙烯醚表面活性剂(NP)明显降低, 显示了较高的表面活性、吸附能力和润湿能力.     

Interaction of Nonionic Surfactant Triton-X-100 with Ionic Surfactants

The interaction in two mixtures of a nonionic surfactant Triton-X-100 (TX-100) and different ionic surfactants was investigated. The two mixtures were TX-100/sodium dodecyl sulfate (SDS) and TX-100/cetyltrimethylammonium bromide (CTAB) at molar fraction of TX-100, α_TX-100 = 0.6. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γ_CMC), maximum surface excess concentration (Γ_max), and minimum area per molecule at the air/solution interface (A _min) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were also determined. Mixtures of both TX-100/SDS and TX-100/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.     

阴离子Gemini表面活性剂和阳离子传统表面活性剂混合体系双水相中囊泡形貌的转变

通过电子显微镜观察了阴离子gemini表面活性剂C₁₁- p-PhCNa和阳离子传统表面活性剂DTAB混合体系双水相中囊泡形貌随体系组成和浓度的转变。结果表明,双水相较浓的一相中形成了多层囊泡,囊泡的大小和壁厚随相的组成和浓度而改变,两组分等电荷混合有利于形成较大且壁较厚的囊泡。分析表明, gemini表面活性剂在聚集体中采取的反式构象可能是其容易形成厚壁多层囊泡的重要原因,C₁₁- p-PhCNa联接链上的苯氧基与DTA⁺之间的p-阳离子相互作用以及两组分相反电性头基之间的静电吸引使囊泡壁的多层结构更加稳定。     

水杨酸钠对阳离子Gemini表面活性剂水溶液中蠕虫状胶束形成和性质的影响

用稳态和震荡剪切实验研究了水杨酸钠(NaSal)对50 mmol·L^-1阳离子Gemini表面活性剂2-羟基-(三亚甲基-α,ω-双十二烷基三甲基溴化铵和三亚甲基-α,ω-双十二烷基三甲基溴化铵, 简写为12-3(OH)-12和12-3-12)水溶液中形成蠕虫状胶束及其性质的影响. 在无盐状态下, 50 mmol·L^-1的12-3(OH)-12或12-3-12在水溶液中仅形成球状或棒状胶束. NaSal可促进上述两体系胶束的生长, 生成蠕虫状胶束. 比较而言, 12- 3(OH)-12对NaSal更敏感, 可以在低盐浓度下生成蠕虫状胶束. 而且与12-3-12体系相比, 12-3(OH)-12生成了更长的蠕虫状胶束. 这些差别在于12-3(OH)-12体系中存在羟基连接链之间的氢键作用, 这增加了12- 3(OH)-12头基的亲水性, 促进了反离子的解离, 增大的胶束表面电荷密度更强烈地结合水杨酸根反离子, 减小了头基间的静电斥力, 反过来又增强了分子间氢键, 致使 12-3(OH)-12胶束迅速生长.