含酰胺基Gemini阳离子表面活性剂的合成

含酰胺基Gemini阳离子表面活性剂的合成     

Gemini阳离子表面活性剂在水溶液中胶团化行为的温度效 应与焓、熵补偿

测定了Cemini阳离子表面活性剂C~m-----s-----C~m·2Br(m=8,10,12,;s=2,6及m=12;s=3,4)水溶液的电导,从电导(k)～表面活性剂浓度(c)曲线的转折点可求得临界胶团浓度cmc.实验发现,Gemini阳离子表面活性剂的胶团化倾向明显强于其“单体分子”)即单离子头基单烷烃链表面活性剂)。根据质量作用模型计算了胶经过程的吉布氏能、焓和熵的改变。结果表明Gemini表面活性剂聚集机理和其对应的“单体分子”类似,主要来自熵驱动。所有的焓/熵补偿图均呈现良好的线性关系,补偿直线在γ轴的截距随s减小而变小,这意味着具有较小s的Gemini表面活性剂倾向于生成稳定的胶团。     

新型表面活性剂研究进展--Bola型表面活性剂与Gemini型表面活性剂

对两类新型表面活性剂--Bola型表面活性剂和Gemini型表面活性剂,从结构特点、研究历史、水中的溶解性与Krafft点、表面活性与表面吸附、临界胶团浓度、水中的聚集体类型与转化、研究前景等方面进行综述.     

油酸酰胺基季铵盐Gemini表面活性剂的制备及性能

以油酸酰胺丙基二甲基胺、1,3-二氯-2-丙醇、1,4-二溴-2-丁烯和1,4-二溴丁烷为原料,分别合成了3种不同连接基团的油酸酰胺基季铵盐阳离子Gemini表面活性剂GS-1、GS-2和GS-3。通过傅里叶变换红外光谱(FT-IR)和核磁共振波谱(1 H NMR)对其结构进行表征,并对其Krafft温度、表面活性、乳化性能、泡沫性能、润湿性等性能进行了测定。结果表明,成功制备了3种Gemini表面活性剂GS-1、GS-2和GS-3,且其Krafft温度均小于0℃,为其低温环境下使用,仍然保持较高表面活性提供了理论可能性。GS-1、GS-2和GS-3的临界胶束浓度(CMC)分别为7.7×10^-5、7.08×10^-5和2.63×10^-6 mol/L,和预期结果一致,Gemini表面活性剂的CMC比传统的单链表面活性剂低1~2个数量级;另外,表面活性剂GS-1、GS-2和GS-3均表现出良好的表面活性、乳化性能和泡沫稳定性。     

新一代表面活性剂: Geminis

表面活性剂Gemini (或称dimeric) 是由两个单链单头基普通表面活性剂在离子头基处通过化学键联接而成, 因而阻抑了表面活性剂有序聚集过程中的头基分离力, 极大提高了表面活性。与当前为提高表面活性而进行的大量尝试, 如添加盐类、提高温度或将阴离子表面活性剂与阳离子表面活性剂混合相比较, Gemini 表面活性剂是概念上的突破, 因而被誉为新一代的表面活性剂。     

动态光散射法研究季铵盐Gemini表面活性剂的胶团化行为

用动态光散射技术在10～70℃温度范围内,通过测定胶团的平均流体力学半径随温度、盐浓度和联接基团长度的变化情况,研究联接基团为聚亚甲基链的阳离子季铵盐Gemini表面活性剂胶团在无机盐介质中的长大规律.实验结果表明,增加盐量、降低温度和减小联接基团的长度均使平均流体力学半径变大,Gemini表面活性剂胶团长大时是由球状转变为棒状.从实验测定的平流体力学半径求算了支配球-棒转变的平衡常数及热力学函数值,并用NNLS(non-negatively constrainedleast square)算法对胶团的粒径分布情况进行了分析.此外,对具有短联接基团的Gemini表面活性剂胶团长大所具有的独特性质进行了讨论.     

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.     

联接基长度对Gemini表面活性剂流变性质的影响

用毛细管振荡剪切流动法研究了联接基团为聚亚甲基链的阳离子Gemini表面活性剂的流变性质。实验结果表明,无论是普通单链单头基或Gemini表面活性剂,其流变性质主要由胶团的大小和形状所决定;随着联接基团长度的增加,胶团的轴比率变小,导致流动阻力减小,粘度降低。此外对于球形和棒状胶团溶液,其流变性质主要以粘性为主．弹性可忽略不计。在低剪切速率下,溶液属于牛顿型流体;而在高剪切速率下,则表现出准塑性流体性质。     

新型阴离子Gemini表面活性剂与非离子表面活性剂C10E6混合溶液的胶团化的研究

研究了烷基苯磺酸盐Gemini表面活性剂Ia与非离子表面活性剂C10E6溶液混合胶团中分子间的相互作用. 通过表面张力法测定了Ia 和C10E6不同比例不同温度下的临界胶束浓度(cmc). 结果表明, 两种表面活性剂以任何比例复配的cmc比单一表面活性剂的cmc都低, 表现出良好的协同效应. 传统型非离子表面活性剂C10E6、Gemini表面活性剂Ia及混合物的cmc都随着温度升高而降低. 而且, 任何配比的混合胶团中两种表面活性剂分子间的相互作用参数β都是负值, 这说明两种表面活性剂在混合胶团中产生了相互吸引的作用. 混合表面活性剂体系的胶团聚集数比单一Ia的大, 但比单一C10E6的小. 向Gemini表面活性剂Ia胶束中加入非离子表面活性剂C10E6会使胶束的微观极性变小.     

芳香反离子与离子表面活性剂胶团的相互作用

用紫外吸收光谱的方法研究了多种芳香反离子与离子表面活性剂胶团之间的相互作用。发现阳离子表面活性剂和阴离子表面活性剂胶团对芳香反离子的吸收光谱有着显著不同的影响,芳香反离子结构的细微变化可导致光谱特性显著不同。这被解释为阳离子表面活性剂胶团与芳香环之间的阳离子-π相互作用。阳离子-π相互作用需要阳离子表面活性剂分子与芳香反离子具有合适的相对位置与距离。通过测定各混合体系的吸附量证明,不同的芳香反离子在胶团表面有不同的排列方式。NMR的实验结果支持了上述解释。     

含有酰胺基或酯基的可降解阳离子Gemini表面活性剂在水溶液中的聚集行为

In the last thirty years, Gemini surfactants with various structures have been designed, synthesized, and demonstrated to show superior physicochemical properties. However, the utilization of non-degradable surfactants, including these Gemini surfactants, poses a threat to the environment; hence, degradable Gemini surfactants are desirable. Herein, biodegradable cationic Gemini surfactants with amide or ester groups in the hydrophobic chains or the spacer were synthesized. A monomeric surfactant containing an amide group and a Gemini surfactant with amide groups both in the hydrophobic chains and the spacer were synthesized for comparison. The effects of amide group location on the aggregation behavior of Gemini surfactants were studied systematically. The differences between the Gemini surfactants with amide groups and Gemini surfactants with ester groups were evaluated by comparing their aggregation behavior and hydrogen bonding formation. The Gemini surfactants with amide groups (C₁₂A-C_n-AC₁₂) in the chains showed much larger exothermic ΔH_mic and more negative ΔG_mic values than those of the corresponding monomeric surfactant C₁₂A; besides, their critical micelle concentration (cmc) was more than one order of magnitude lower than that of C₁₂A. The amide groups located in the hydrophobic alkyl chains promoted hydrogen bonding formation and self-assembly of the Gemini surfactants C₁₂A-C_n-AC₁₂. Moreover, ¹H NMR spectra revealed that the co-effect of a short spacer and hydrogen bonding leads to slow exchange of the C₁₂A-C₂-AC₁₂ molecules between the monomer and the aggregate. For the Gemini surfactant series C₁₂-AC_nA-C₁₂, the amide groups notably increased the spacer length, and largest cmc value and smallest exothermic ΔH_mic value were observed for C₁₂-AC₂A-C₁₂ instead of C₁₂-AC₆A-C₁₂. In C₁₂-AC₁₂A-C₁₂, the spacer was long and sufficiently flexible to adopt a "U"-shaped conformation above the cmc, and it acted as the hydrophobic part of the surfactant, as confirmed by ¹H NMR spectra. Among the Gemini surfactant with amide groups in both the spacer and the hydrophobic alkyl chains, C₁₂A-AC₆A-AC₁₂ had a smaller cmc and I₁/I₃ ratio as well as more exothermic ΔH_mic values than those of C₁₂A-C₆-AC₁₂ and C₁₂-AC₆A-C₁₂. ¹H NMR spectra indicated that an ester-alcohol structural equilibrium exists during aggregation for the Gemini surfactants with ester groups. In addition, the Gemini surfactants with ester groups formed water-mediated hydrogen bonds in the aggregates. This water-mediated hydrogen bonding between ester groups was weaker than the direct hydrogen bonding between amide groups. Therefore, the Gemini surfactants with ester groups, C₁₂E-C₆-EC₁₂ and C₁₂-EC₆E-C₁₂, exhibited lower surface activity, a larger micelle ionization degree, higher micropolarity, and smaller exothermic ΔH_mic and less negative ΔG_mic values than their counterparts with amide groups, C₁₂A-C₆-AC₁₂ and C₁₂-AC₆A-C₁₂.     

碳量子点阳离子表面活性剂的多功能性

碳量子点以其多彩的荧光及廉价而丰富的制备原料引起人们的广泛兴趣。至今,已有大量关于碳量子点制备及其荧光性能直接利用的文献报道。若采用恰当的方法对碳量子点进行化学修饰,则可以将其转化为实用的精细化学品,从而拓展碳量子点的应用领域。本文报道了一种碳量子点阳离子表面活性剂的制备方法。首先,乙二胺四乙酸、二乙胺及双氧水的混合水溶液经水热处理,获得碳量子点(以OX-CQDs表示),再以氯代正构十二烷对其进行季铵化修饰,获得新型碳量子点阳离子表面活性剂(以OX-CQDs-C₁₂H₂₅表示)。OX-CQDs-C₁₂H₂₅具有良好的降低水的表面张力和减小水接触角的能力,水的界面张力能降低至26.7 mN∙m⁻¹,其性能超过了一些新型的Gemini型阳离子表面活性剂;季铵化的修饰也大大提高了OX-CQDs对大肠杆菌的抑菌能力,低至0.41 mg∙mL⁻¹的OX-CQDs-C₁₂H₂₅溶液其抑菌率接近100%。表面活性剂,抑菌性和荧光性能赋予了OX-CQDs-C₁₂H₂₅的多种功能性。     

Gemini表面活性剂与DNA在气/液界面上的相互作用

在气/液界面上, 阳离子表面活性剂可以通过静电作用与阴离子型的脱氧核糖核酸(DNA)分子形成复合膜, 并压缩沉积得到LB(Langmuir-Blodget)膜. 利用表面压-表面积(π-A)曲线、原子力显微镜(AFM)和石英晶体微天平(QCM)研究了阳离子Gemini表面活性剂([C₁₈H₃₇(CH₃)₂N⁺-(CH₂)_s-N⁺(CH₃)₂C₁₈H₃₇]·2Br^-, 简写为18-s-18, s=3, 4, 6, 8, 10, 12)与DNA(双链DNA(dsDNA), 单链DNA(ssDNA))之间的相互作用, 并对18-s-18在不同下相表面的分子面积进行了比较. 实验结果表明连接基团和下相的DNA对Gemini表面活性剂在气/液界面上的性质有很大影响. 此外, Gemini表面活性剂在界面上对DNA的吸附能力与它们之间的相互作用方式密切相关.     

Active control of surface properties and aggregation behavior in amino acid-based Gemini surfactant systems

Two types of Gemini surfactants containing a disulfide bond in the spacer, sodium dilauroyl cystine (SDLC) and sodium didecamino cystine (SDDC), were synthesized, and their surface properties and aggregation behavior in aqueous solution were studied by means of surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence. During the transition of the Gemini surfactants to their corresponding monomers through the reduction of disulfide bonds, the surface tensions of their aqueous solutions, as well as their aggregation behavior, changed greatly. The reduction of SDLC and SDDC led to disruption of the vesicle, and the oxidation of corresponding monomers to Gemini surfactants led to vesicle re-formation. These results demonstrated the control of surface properties and aggregation behavior by the reversible transition between the Gemini surfactant and its monomer via reduction/oxidation reactions.     

Antibacterial and Antifungal Activities—Surface Active Properties Relation of Novel Dischiff Base Cationic Gemini Amphiphiles Bearing Homogeneous Hydrophobes

A novel series of cationic Gemini amphiphiles containing Dischiff base species were synthesized and their chemical structures were determined using different analytical tools. Their surface properties were determined using surface tension measurements. The adsorption and micellization thermodynamic parameters were calculated using Gibb's equations at 25°C. The surface parameters were also determined including critical micelle concentration, effectiveness, efficiency, maximum surface excess, minimum surface area, interfacial tension, and emulsification power. The synthesized cationic Gemini surfactants were evaluated as bactericides for gram negative and gram positive bacteria and also against sulfur reducing bacteria (SRB). The results of the cytotoxicity of the synthesized compounds against the targeted bacterial strains were promising and completely dependent on the surface activity of these compounds.     

磺酸盐型Gemini表面活性剂合成研究进展

磺酸盐型Gimini表面活性剂是一类新型的阴离子表面活性剂,它由联结基团通过化学键将2个或多个单体磺酸盐型表面活性剂连接在一起,由此产生高表界面活性,低临界胶束浓度值,增强了洗涤能力,与传统的阴离子表面活性剂有较好的复配性,奇异的流变特性和良好的抗盐性等一系列的性质,从而具有广泛的应用前景。 本文以原料来源不同分类,综述了一系列磺酸盐型Gemini表面活性剂的合成方法,展望了合成磺酸盐型Gemini表面活性剂的研究方向。     

荧光探针法研究双子型阳离子表面活性剂与明胶的相互作用

利用荧光探针法研究了双子型阳离子表面活性剂与明胶的相互作用,考察了此类表面活性剂的分子结构和明胶对临界胶团浓度(cmc)、胶团聚集数(N_agg)和胶团微极性的影响.结果表明,当双子型阳离子表面活性剂的疏水基增长时,cmc减少,N_agg增加,胶团的微极性降低;加入明胶后,双子型阳离子表面活性剂的N_agg减少,cmc和胶团微极性增加.     

季铵盐型Gemini表面活性剂在金表面的吸附行为

以邻苯二酚(CC)为电化学探针, 利用循环伏安、交流阻抗等方法研究了不同阳离子Gemini表面活性剂(C16H33(CH3)2N-C4H8-N(CH3)2C16H33 (C16-C4-C16)、C12H25(CH3)2N-C4H8-N(CH3)2C12H25 (C12-C4-C12)、C8H17(CH3)2N-C4H8-N(CH3)2C8H17 (C8-C4-C8))在金电极表面的吸附性能. 结果表明, CC在KNO3溶液中可产生两对峰; 当向溶液中加入阳离子Gemini表面活性剂时, 第一对峰降低, 第二对峰升高, 峰电位差变大; 碳链长的表面活性剂对CC的氧化还原峰的影响较大. 同样, 碳链长的表面活性剂使电极界面的阻抗增大较多, 使石英晶片的频率变化较大. 根据CC的第一个氧化峰的面积随表面活性剂吸附的变化, 估测了它们的吸附模式. 发现这三种表面活性剂在金电极表面的吸附基本符合Langmuir吸附模型.     

pH-responsive surface activity and solubilization with novel pyrrolidone-based Gemini surfactants

A new series of pH-responsive Gemini surfactants with 2-pyrrolidone head groups, N,N'-dialkyl-N,N'-di(ethyl-2-pyrrolidone)ethylenediamine (Di-C(n)P, where n = 6, 8 10, 12), were synthesized and characterized by (1)H NMR, (13)C NMR, ESI-MS, and elemental analysis. The surface activity and micellization behavior at acidic, neutral, and basic conditions were characterized by equilibrium surface tension and fluorescence techniques. It was found that the surface activity of Di-C(n)P depends on the pH of aqueous solutions due to the protonation state of surfactant molecules when pH was varied. The new compounds have lower cmc and γ(cmc) in comparison with that of m-2-m type conventional cationic Gemini surfactants and gluconamide-type nonionic Gemini surfactants. Fluorescence data confirm that micelles are formed when the concentration is above the cmc. Since micellization is of fundamental importance in surfactant applications such as solubilization, microemulsion, and related technologies, the significant difference in cmc at different pH of this new Gemini surfactant is employed to solubilize cyclohexane. The preliminary result indeed shows that the solubilization capacity of Di-C(n)P can be tuned by pH.