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.     

胶束模拟酶的研究——1.手性胶束中酮的不对称还原

在( )和(-)-N-十六烷基—N,N-二甲基-α-苯乙铵溴化物(1a和1b)及N-十二烷基-N,N-二甲基麻黄素溴化铵(2)等表面活性剂形成的手性胶束溶液中,以NaBH_4还原潜手性的苯基烷基酮可诱导出不对称中心,生成旋光性的醇。e.e.%最大值可达8.6%。产物醇的构型取决于所用胶束的构型,对只有一个手性中心的胶束1a和1b,产物构型和胶束相反。手性胶束结构对产物的光学得率影响较大。     

胶束模似酶的研究1.手性胶束中酮的不对称还原

在(+)和(-)-N-十六烷基-N,N-二甲基-α-苯乙铵溴化物(1a和1b)及N-十二烷基-N,N-二甲基麻黄素溴化铵(2)等表面活性剂形成的手性胶束溶液中,以NaBH~4还原潜手性的苯基烷基酮可诱导出不对称中心,生成旋光性的醇.e.e.%最大值可达8.6%.产物醇的构型取决于所 用胶束的构型,对只有一个手性中心的胶束1a和1b,.产物构型和胶束相反.手性胶束结构对产物的光学得率影响较大.     

介孔SiO2孔道内Gemini分子有序自组装构筑正相胶束辅助传递OH-离子

利用Gemini型阳离子表面活性剂(顺丁烯二酸二乙酯撑基双[辛烷基二甲基氯/溴化铵], G_8-2-8)在有机反离子水杨酸根(Sal^-)的诱导作用下, 于介孔SiO₂孔道内有序组装, 构筑表面带有季铵基团的正相蠕虫胶束. 胶束外表面有序排布的季铵基团与介孔SiO₂孔道内壁布满的硅羟基共同作用形成环形保水腔室, 即构筑了OH^-传递的有序通道. 通过对G_8-2-8/NaSal 胶束体系的流变学性质研究, 结果表明, 胶束网络结构已经形成. 将G_8-2-8/NaSal胶束网络形成过程引入聚砜(PSF)体系中, 制备出有序OH^-迁移通道的高耐碱性的阴离子导电膜. 相关性能测定结果表明, 随着G_8-2-8质量分数的增加, 电导率、 含水率及离子交换量均呈现上升趋势, 特别是在离子交换量和含水率均较低的情况下, OH^-的迁移效率得到明显提升. 经过400 h的耐碱性测试, 结果表明, 该系列膜的电导率降幅仅为1.5%左右, 且外观形貌无明显变化, 表现出优异的耐碱稳定性.     

甘氨酸衍生物对油酸钠胶束化的影响

以N,N-二甲基甘氨酸甲酯为原料合成了两种甘氨酸衍生物,碘化N,N,N-三甲基甘氨酸甲酯(GE)和碘化N,N,N-三甲基甘氨酸钠盐(SG),并利用电导法研究了稀浓度的GE、SG对油酸钠(NaOA)胶束化的影响.结果表明,随着反离子GE、SG浓度的增加,NaOA/GE或SG体系的临界胶束浓度(cmc)、反离子解离度(α)、胶束化自由能(#Gmic)逐渐降低.通过分析这两种反离子的分子结构,我们得出反离子的疏水性是影响这些热力学参数变化的主要因素,疏水性较强的GE更有利于油酸钠胶束的形成.     

三聚阴离子表面活性剂/阳离子添加剂混合体系的流变行为

表面活性剂的分子结构对蠕虫胶束的形成与性质有着重要影响。本文以十四酸和间苯三酚为起始原料,合成了一种三聚阴离子表面活性剂（2, 2', 2"-（苯基-1, 3, 5-三（氧））-三-十四酸钠,简写为Ph-TrisC₁₄Na）,并通过稳态和动态流变测试,研究了单组分的Ph-TrisC₁₄Na和Ph-TrisC₁₄Na/阳离子添加剂体系的粘弹性质。阳离子添加剂分别为正丁基三甲基溴化铵（C₄TAB）,正己基三甲基溴化铵（C₆TAB）和正辛基三甲基溴化铵（C₈TAB）。结果表明,依赖于独特的分子构型,Ph-TrisC₁₄Na分子自身即可形成蠕虫胶束,使溶液表现出明显的粘弹性。阳离子添加剂的加入可进一步优化Ph-TrisC₁₄Na的分子几何结构,促进蠕虫胶束更为快速地生长。随着阳离子添加剂疏水链长的增加,溶液的粘弹性显著增强,体系微结构对添加剂的敏感性也增加。对于50 mmol·L^-1的Ph-TrisC₁₄Na溶液来说,在C₈TAB与Ph-TrisC₁₄Na的摩尔比为0.5时,体系的零剪切粘度可达1535 Pa·s,蠕虫胶束的长度则达到4.0-7.5 μm。该体系体现出低聚表面活性剂在构筑表面活性剂粘弹溶液方面的优势,可拓展高粘弹性阴离子蠕虫胶束体系的研究范围。     

四甲基溴化铵及不同链长表面活性剂对甲基纤维素-邻甲氧基肉桂酸溶液凝胶化行为的影响

测定了四甲基溴化铵以及表面活性剂十二烷基三甲基溴化铵(DTAB)、十四烷基三甲基溴化铵(TTAB)和十六烷基三甲基溴化铵(CTAB)对甲基纤维素(MC)-4邻甲氧基肉桂酸钠盐(OMC-)体系的凝胶化行为的影响.结果表明:含DTAB、TTAB以及CTAB的MC-OMC溶液的溶胶-凝胶转变温度不随表面活性剂质量分数的变化而变化,但是向MC-OMC溶液中加入四甲基溴化铵,体系的溶胶-凝胶转变温度会显著下降.在含四甲基溴化铵或不同链长表面活性剂的MC-OMC-溶液中,TTAB等表面活性剂分子更倾向于在水溶液中形成球状胶束;四甲基溴化铵与OMC-有着较强的静电作用,会导致MC和OMC-形成的核-壳结构破裂.     

手性胶束中的不对称Micheal反主尖

本文研究了手性表面活性剂N,N-二甲基-N-十二烷基麻黄素溴化铵及N,N-二甲基-N-十六烷基麻黄素溴化铵所形成的手性胶束体系中,以六氢吡啶作为碱催化剂,硝基甲烷或硫酚对查耳酮类化合物的Michael加成反应.     

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.     

新型不对称季铵盐Gemini表面活性剂的合成及其表面活性

以溴代烷和N,N,N′,N′-四甲基乙二胺为原料,经过两步季铵化反应合成了一种新型的不对称型阳离子Gemini表面活性剂——二亚甲基-1-正己基二甲基溴化铵-2-十八烷基二甲基溴化铵(3),其结构经1H NMR和元素分析表征.研究结果表明,3的Krafft点为21.9℃,且聚集能力强.     

Wormlike micelles formed by mixed cationic and anionic gemini surfactants in aqueous solution

The formation and the properties of wormlike micelles in aqueous solutions of mixed cationic and anionic gemini surfactants, 2-hydroxyl-propanediyl-α,ω-bis(dimethyldodecylammonium bromide) (12-3(OH)-12) and O,O'-bis(sodium 2-dodecylcarboxylate)-p-benzenediol (C(12)?C(12)), have been studied by steady-state and dynamic rheological measurements at 25°C. With the addition of a small amount of C(12)?C(12) into the solution of 12-3(OH)-12, the total surfactant concentration of which was always kept at 80 mmol L(-1), the solution viscosity was strongly enhanced and its maximum was much larger than that of the mixed system of propanediyl-α,ω-bis(dimethyldodecylammonium bromide) (12-3-12) and C(12)?C(12). The results of dynamic rheology measurements showed that 12-3(OH)-12/C(12)?C(12) formed longer wormlike micelles in comparison with 12-3-12/C(12)?C(12). This was attributed to the effect of hydrogen bonding occurring between 12-3(OH)-12 molecules, which was an effective driving force promoting micellar growth. As few C(12)?C(12) participated in the micelles, the electrostatic attraction between the oppositely charged head groups of 12-3(OH)-12 and C(12)?C(12) made the molecules in the aggregates pack more tightly. This reinforced the hydrogen-bonding interactions and greatly promoted the micellar growth.     

Binary mixtures with novel monomeric and dimeric surfactants: influence of the head group nature and number of hydrophobic chains on non-ideality

The micellization and micellar growth in the mixtures of N,N-dimethyl, N-phenyl,N-dodecylammonium bromide, PH12, N,N-dimethyl,N-ciclohexylmethyl,N-dodecylammonium bromide, CH12, and their two dimeric counterparts m-dimethylphenyl-α-ω-bis(dodecyldimethylammonium) bromide, 12PH12, and m-dimethylciclohexyl-α-ω-bis(dodecyldimethylammonium) bromide, 12CH12, with dodecyltrimethylammoniumbromide, DTAB, and with N-decanoyl N-methylglucamide, MEGA10, were investigated at 303 K. Circular dichroism, CD, experiments showed the formation of mixed micelles. Two-dimensional, 2D, rotating frame nuclear Overhauser effect spectroscopy (ROESY) experiments indicated that the arrangement of the rings in the pure and mixed micelles is similar, with the rings bent into the micelle interior avoiding contact with water. Application of different theoretical approaches shows that PH12 and CH12 mixtures with DTAB and with MEGA10 behave almost ideally. The binary systems of 12PH12 and 12CH12 with DTAB and with MEGA10 show a non-ideal behavior. An increment in the solution mole fraction of MEGA10 and DTAB diminishes the tendency of the micellar aggregates to grow.     

Surface properties, aggregation behavior and micellization thermodynamics of a class of gemini surfactants with ethyl ammonium headgroups

Cationic gemini surfactant homologues alkanediyl-α,ω-bis(dodecyldiethylammonium bromide), [C(12)H(25)(CH(3)CH(2))(2)N(CH(2))(S)N(CH(2)CH(3))(2)C(12)H(25)]Br(2) (where S=2, 4, 6, 8, 10, 12, 16, 20), referred to as C(12)C(S)C(12)(Et) were synthesized systematically. This paper focused on various properties of the above gemini surfactants in order to give a full understanding of this series of surfactants. The following points are covered: (1) surface properties, which include (i) effect of the spacer carbon number on the general properties and (ii) the effect of added NaBr on the general surface properties; (2) aggregation behavior in bulk solution, including (i) morphologies of above gemini surfactants classed as having short spacers, middle-length spacers and long spacers and (ii) superior vesicle stability against high NaBr concentration for the long spacer gemini surfactants; (3) thermodynamic properties during micellization and the effect of spacer carbon number on them; and (4) perspectives for the further use and application of these compounds.     

Gemini表面活性剂乙烷基-α,ω-双十四烷基二甲基溴化铵产生的高稳定泡沫

报道了由gemini表面活性剂乙烷基-α,ω-双十四烷基二甲基溴化铵(14-2-14)产生的高稳定泡沫体系.泡沫塌陷到初始高度一半所对应的时间(t1/2)用来表征泡沫的稳定性.测得14-2-14体系的t1/2高达961min,远大于乙烷基-α,ω-双十二烷基二甲基溴化铵(12-2-12)产生泡沫的t1/2(754min),表明带有一根短联接链和两条长尾链的gemini表面活性剂是高效的泡沫稳定剂.为了揭示界面弹性与泡沫稳定性之间的关联,测量了表面活性剂吸附膜的扩张流变行为.在指定的表面过剩量下,吸附膜的高频极限弹性再一次被发现与泡沫稳定性相关,较大的极限弹性很好地对应更加稳定的泡沫.     

Study of the reaction 2-(p-nitrophenyl)ethyl bromide + OH⁻ in dimeric micellar solutions

The dehydrobromination reaction 2-(p-nitrophenyl)ethyl bromide + OH? was investigated in several alkanediyl-α-ω-bis(dodecyldimethylammonium) bromide, 12-s-12,2Br? (with s = 2, 3, 4, 5, 6, 8, 10, 12) micellar solutions, in the presence of NaOH 5 × 10?3 M. The kinetic data were quantitatively rationalized within the whole surfactant concentration range by using an equation based on the pseudophase ion-exchange model and taking the variations in the micellar ionization degree caused by the morphological transitions into account. The agreement between the theoretical and the experimental data was good in all the dimeric micellar media studied, except for the 12-2-12,2Br? micellar solutions. In this case, the strong tendency to micellar growth shown by the 12-2-12,2Br? micelles could be responsible for the lack of accordance. Results showed that the dimeric micelles accelerate the reaction more than two orders of magnitude as compared to water.     

CO2 responsive wormlike micelles based on sodium oleate,potassium chloride and N,N-dimethylethanolamine

The anionic surfactant sodium oleate (NaOA) can self-assemble in aqueous solution in the presence of counter-ion inorganic salts to form wormlike micelles (WLMs), which exhibited viscoelastic behavior. In this paper, KCl was used to induce the formation of wormlike micelles with sodium oleate. In this process, we found that the addition of N, N-dimethylethanolamine (DMEA) can destroy the structure of WLMs leading significant decrease of viscosity. However, after introducing CO₂ into the ternary solution (KCl-NaOA-DMEA), the WLMs can be regenerated due to the electrostatic interaction between the protonated DMEA and the anionic surfactants. The addition of sodium hydroxide (NaOH) causes the electrostatic interaction between OA^- and DMEAH⁺ be destroyed, which results in the wormlike micelles becoming spherical micelles of lower viscosity. The transition of WLMs with high viscosity and low viscosity spherical micelles can be repeated several times by using CO₂ and NaOH.     

Anionic wormlike micellar fluids that display cloud points: rheology and phase behavior

We report our investigations into the self-assembly of sodium oleate (NaOA) in the presence of a binding salt (triethylammonium chloride, Et(3)NHCl) simple salt (potassium chloride, KCl). Both salts promote the growth of long, wormlike micelles in NaOA solutions, thereby increasing the fluid viscosity. The significant difference with the Et(3)NHCl salt is that it also modifies the phase behavior of NaOA solutions. Specifically, NaOA/Et(3)NHCl solutions display cloud points upon heating, followed by phase separation into two liquid phases. Such cloud point behavior is rarely observed in ionic surfactant systems, although it is common in nonionic surfactant solutions. Interestingly, while cloud points are not observed with KCl, the addition of KCl to NaOA/Et(3)NHCl solutions further lowers the cloud point temperature. Also, in the case of tetraethylammonium halide salt, neither a cloud point nor an increase in viscosity is observed. The clouding in the case of Et(3)NHCl is attributed to the temperature-induced aggregation of anionic micelles whose surface is covered by bound counterions.     

(1)H NMR and viscometric studies on cationic gemini surfactants in presence of aromatic acids and salts

In this paper, we are reporting the influence of addition of aromatic acids (anthranilic and benzoic acid) and their sodium salts on the micellar morphological changes in three cationic gemini surfactant solutions, viz. 5 mM tetramethylene-1,4-bis(N-hexadecyl-N,N-dimethylammonium bromide), 10 mM pentamethylene-1,5-bis(N-hexadecyl-N,N-dimethylammonium bromide), and 10 mM hexamethylene-1,6-bis(N,-hexadecyl-N,N-dimethylammonium bromide). The solubilization site of the counterions (obtained from the additives) near the micellar surface are inferred by 1H NMR. The behavior is explained in the light of binding of counterions to the micelle as well as the nature of the functional group attached to the additive.     

Resiliently spherical micelles of alkyltrimethylammonium surfactants with multivalent, hydrolyzable counterions

A series of C(12)-C(16) alkyltrimethylammonium surfactants with hydrolyzable phosphate (PO(4)(3-), HPO(4)(2-), and H(2)PO(4)(-)), oxalate (HC(2)O(4)(-) and C(2)O(4)(2-)), and carbonate (HCO(3)(-) and CO(3)(2-)) counterions have been prepared, and their micellar solution behavior has been characterized. Critical micelle concentrations were measured using electrical conductivity and were found to depend on both the counterion and its hydrolysis state. All monovalent counterions bind less strongly to the micelle surface than does bromide or chloride, whereas multivalent species bind more strongly. Small-angle neutron scattering reveals that, unlike alkyltrimethylammonium bromides and chlorides, micelles are small and spherical in the presence of hydrolyzable counterions of all valences and remain spherical even in the presence of added electrolyte. This is consistent with the strong solvation of even strongly bound hydrolyzable counterions, which prevents the screening of repulsions between adjacent headgroups necessary for sphere-cylinder transformations. Salts of multivalent hydrolyzable counterions could thus be used to control the micelle structure in novel ways.