阴离子Gemini表面活性剂在油/水界面行为的分子动力学模拟

采用分子动力学方法研究了磺酸盐型阴离子Gemini表面活性剂在油/水界面的吸附行为, 考察了不同长度的连接基(Spacer)对表面活性剂在界面的聚集形态及界面性质的影响. 密度分布和微观结构信息显示, Gemini表面活性剂能在油/水界面形成单层膜结构. Gemini表面活性剂能使油/水界面的厚度显著增大, 并使界面形成能降低. 当连接基为6个碳时, 此类磺酸盐型Gemini表面活性剂的界面厚度最大, 形成的界面最稳定. 连接基长度对Gemini表面活性剂单层膜周围的水分子和Na⁺的吸附结构影响不大, 但是能影响水分子的扩散行为.     

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。     

两性离子表面活性剂的合成及其表面性质

合成了一类含季铵基和磺酸基结构的非对称Gemini两性离子表面活性剂;利用红外光谱、质谱、离子定性试验验证了合成产物的分子结构,并测定了其表面性质.结果表明,目标产物的分子结构符合设计预期;五种非对称Gemini两性离子表面活性剂的表面张力在30mN/m左右,临界胶束浓度达到10-4~10-5数量级.此外,虽然非对称Gemini两性离子表面活性剂的起泡性能比相应单链型表面活性剂的稍差,但其稳泡性明显优于后者.     

不同电性Gemini表面活性剂界面扩张性质

利用Langmuir槽法研究了含聚氧乙烯醚链中间链的两性Gemini表面活性剂C8E4NC12、阳离子Gemini表面活性剂C12NE3NC12和阴离子Gemini表面活性剂C8E4C8在空气/水表面和癸烷/水界面上的扩张性质,考察浓度对3种Gemini表面活性剂溶液表、界面扩张性质的影响.结果表明,由于分子间存在库仑引力,两性Gemini分子表现出较高的扩张弹性和粘性,且界面扩张性质类似于表面.对于有相同电荷Gemini分子,C8E4C8分子中的刚性苯环导致其疏水长链在表面上的取向不同于C12NE3NC12分子,两者表现出不同的表面扩张性质;而油分子能改变同电荷Gemini分子中长链烷基的取向,造成其界面扩张弹性和粘性远低于表面.提出了不同电性Gemini分子在界面排布的示意图,并利用弛豫过程的特征参数进行了验证.     

《化学通报》网络版（Chemistry Online）2006年第7期论文摘要

[w077]精氨酸类表面活性剂的合成与性能Syntheses and Properties of Arginine-based Surfactants丁兆云郝爱友*(山东大学化学与化工学院济南250100)精氨酸类表面活性剂是一类基于天然再生资源、低毒、生物降解性好、表面活性优良且具有广谱抑菌性的表面活性剂,被誉为绿色表面活性剂。本文综述了其中三类精氨酸表面活性剂:N-酰基精氨酸酯盐酸盐、Gemini类精氨酸表面活性剂和1,2-二烷酰基-3-(N-乙酰基精氨酰)甘油盐酸盐的合成方法、物化性能和生物性质。Arginine-based surfactants,called green surfactants,show low toxicity,quick bi…     

萘(苯)双十四烷基双磺酸钠Gemini表面活性剂合成及性能研究

Gemini表面活性剂因其特殊的分子结构，使它在降低表面张力的效率与效能，以及起泡性、乳化力、润湿性等方面的性能大大优于传统表面活性剂。由此，Gemini表面活性剂成为近年日用化工及胶体与界面化学领域研究的热点课题之一。目前，Gemini表面活性剂优良的表化性能已被广泛认识，相应的理论研究趋于成熟，但Gemini表面活性剂在实际生产中的应用却不多见，究其原因主要是Gemini表面活性剂大都合成路线长，产品价格高，从而限制了它们的使用。本文拟以α-十四烯烃磺酸为原料，采用“一步法”合成萘（苯）双十四烷基双磺酸钠Gemini表面活性剂，其合成路线和反应条件均与现在生产α-烯烃磺酸钠相似，但成本却低于后者，有望实现高的性能价格比。     

Gemini型甜菜碱表面活性剂合成进展

Gemini型甜菜碱结合了甜菜碱和Gemini型表面活性剂的优点,可以在较低浓度下达到超低油水界面张力、配伍性好、耐温耐盐性好、Krafft点以及吸附量低,被广泛应用于日用化学、化学化工、纳米材料、生物技术和石油开采等领域。本文基于间隔基的类型介绍了近年来Gemini型甜菜碱表面活性剂方面的最新研究进展。重点阐述了对称胺型、三嗪环型、二卤代物型Gemini甜菜碱的合成方法,并从原料成本、产率、反应周期以及产物的性能等方面对合成方法进行了分析和比较。最后对Gemini型甜菜碱表面活性剂的发展进行了展望。     

C12-m-C12型阳离子Gemini表面活性剂在煤沥青表面的润湿性

利用座滴法和电泳法研究了阳离子Gemini表面活性剂C₁₂-m-C₁₂·2Br^-(m=4、6、8、10)在煤沥青表面的润湿性质及吸附机理。结果表明, 表面张力均随表面活性剂浓度的增大而减小, 超过临界胶束浓度(CMC)后趋于平稳, 接触角θ和铺展系数S的变化趋势与表面张力类似; 在所研究浓度范围内,C₁₂-10-C₁₂型表面活性剂的γ_lg~cosθ曲线符合Zisman理论, 且侵湿功(W_i)与表面张力也呈线性关系; 煤沥青表面的Zeta电位随表面活性剂浓度的增加从负电变为正电,最后趋于平稳, 且零电位对应的浓度比CMC至少低一个数量级; C₁₂-8-C₁₂型Gemini表面活性剂能显著改变煤沥青表面的润湿性. 由Gemini表面活性剂在煤沥青表面润湿结果及Zeta电位可以看出, C₁₂-m-C₁₂型Gemini表面活性剂在煤沥青表面的润湿是静电作用和范德华吸附共同作用的结果; 润湿过程可分为三个阶段。     

支链醇对Gemini表面活性剂表面活性和胶束化行为的影响

Gemini表面活性剂是一类高效的新型表面活性剂,而醇是工业界和日化领域最常采用的表面活性剂助剂,因此研究不同结构的醇对Gemini表面活性剂表面活性和胶束化行为的影响规律和机理对于促进Gemini表面活性剂的发展和实际应用具有重要意义.利用表面张力、电导、等温滴定微量热,低温透射电镜和核磁共振研究了直链醇1-戊醇和具有相同主链的支链醇2-己醇与3-庚醇对具有不同长度连接基团阳离子季铵盐型Gemini表面活性剂C₁₂C_SC₁₂Br₂ （S=2,4,6,8,10,12）的表面活性和胶束化行为的影响,结果发现,支链醇能够显著影响表面活性剂在气/液界面的排布,使得C₂₀ （使溶剂的表面张力降低20 mN/m所需的表面活性剂浓度）和γ_CMC （CMC时表面张力值）随醇支化度的增加而显著降低,而支链醇对表面活性剂在溶液中的临界胶束浓度以及胶束的尺寸和形貌均没有明显影响,同时这些醇对Gemini表面活性剂的影响与连接基团的长度相关.阐述了上述结果产生的机理,将有助于指导如何选择合适结构的醇助剂去调控Gemini表面活性剂的表面和溶液性质.     

m-6-m型Gemini双季铵盐表面活性剂与DNA的相互作用

合成了5种m-6-m型Gemini双季铵盐表面活性剂,在对产物结构和表面活性进行分析的基础上,分别采用紫外分光光度法和荧光分光光度法考察了m-6-m型Gemini双季铵盐表面活性剂与DNA的相互作用.结果表明,m-6-m型Gemini表面活性剂的CMC随烷基疏水链的增长呈逐渐下降趋势.几种表面活性剂均没有使DNA的紫外吸收峰发生红移或蓝移现象,说明复合物无嵌插作用或氢键形成,表面活性剂与DNA作用后的吸光度随表面活性剂浓度的增大而增强,当表面活性剂的浓度相同时,吸光度随疏水链的增大而逐渐减弱.Gemini表面活性剂浓度增大导致荧光强度降低,表面活性剂与DNA作用时的猝灭为静态猝灭,随着疏水链长度的增长,荧光猝灭常数降低,表面活性剂与DNA之间的作用力减弱.     

松香改性制备表面活性剂及其应用研究进展

从松香出发,可制备阴离子、阳离子、非离子和两性离子等四类表面活性剂。文章综述了国内外近年来以松香和改性松香为主要原料合成表面活性剂及其应用方面的研究进展,分别讨论了这些表面活性剂在使用过程中的主要优势和存在问题。     

Dimeric and oligomeric surfactants. Behavior at interfaces and in aqueous solution: a review

Dimeric and oligomeric surfactants are novel surfactants that are presently attracting considerable interest in the academic and industrial communities working on surfactants. This paper first presents a number of chemical structures that have been reported for ionic, amphoteric and nonionic dimeric and oligomeric surfactants. The following aspects of these surfactants are then successively reviewed the state of dimeric and oligomeric surfactants in aqueous solutions at concentration below the critical micellization concentration (cmc); their behavior at the air/solution and solid/solution interfaces; their solubility in water, cmc and thermodynamics of micellization; the properties of the aqueous micelles of dimeric and oligomeric surfactants (ionization degree, size, shape, micropolarity and microviscosity, solution microstructure, solution rheology, micelle dynamics, micellar solubilization, interaction between dimeric surfactants and water-soluble polymers); the mixed micellization of dimeric surfactants with various conventional surfactants; the phase behavior of dimeric surfactants and the applications of these novel surfactants.     

Structural Parameters of Mixed Nonionic Surfactants Microemulsions

In this study, we estimated the structural parameters of water/mixed nonionic surfactants/R (+)-limonene microemulsions. The mixed surfactants are sucrose laurate and ethoxylated mono-di-glyceride. U-type microemulsion region was observed in these systems. It was found that changes in the surfactants mixing ratio, surfactants contents and oil/water weight ratio in the microemulsions incite a considerable change in the aggregation number, core radius and interfacial area per mixed surfactants head groups in the formed microemulsions. The interfacial area per mixed surfactant head groups increases while the aggregation number decreases with the increase in the ethoxylated mono-di-glyceride mass fraction in the mixed surfactants. The For an oil/water weight content equals unity, the interfacial area per mixed surfactants head groups is constant for mixed surfactants contents below 35 wt%. For mixed surfactants contents above 35 wt% the interfacial area per mixed surfactants head groups decrease and stabilizes at the lower value. The aggregation number decreases with the increase in the mixed surfactants contents. The aggregation number decreases also with the increase in the oil/water weight ratio at fixed mixed surfactants content.     

聚氨酯类反应型高分子表面活性剂的研究进展

反应型高分子表面活性剂兼有反应型表面活性剂可以以牢固的共价键键合到聚合物粒子上,有效避免了表面活性剂在聚合物膜中迁移的优点和高分子表面活性剂性质稳定、耐水性好、低毒或无毒的优点,是一种备受关注的新型表面活性剂,其中含有双键的聚氨酯类可聚合型高分子表面活性剂因其软硬度可调、反应活性高等优点而成为此类研究的一个新热点。本文综述了国内外聚氨酯类反应型高分子表面活性剂最新研究概况,简述了其合成路线和应用性能,并对未来的研究方向进行了预测。     

Cationic ester-containing gemini surfactants: chemical hydrolysis and biodegradation

Two cationic gemini surfactants having ester bonds between the hydrophobic tail and the cationic moiety have been synthesized. The ester bonds were either with the ester carbonyl group away from the positive charge (esterquat type arrangement) or facing the positive charge (betaine ester type arrangement). The chemical hydrolysis of the surfactants was investigated and compared with the hydrolysis of the corresponding monomeric surfactants. The betaine ester type of surfactants was found to hydrolyze much faster than the esterquat surfactants. It was also seen that above the critical micelle concentration the gemini surfactants were much more susceptible to alkaline hydrolysis than the corresponding monomeric surfactants. The biodegradation of the geminis and the monomeric surfactants were also studied. It was found that whereas the monomeric surfactants were rapidly degraded, the two gemini surfactants were more resistant to biodegradation and could not be classified as readily biodegradable. The 60% biodegradation was reached after 35-40 days. Thus, there was no correlation between rate of chemical hydrolysis and rate of biodegradation.     

Synthesis and aqueous solution properties of homologous gemini surfactants with different head groups

A series of homologous gemini surfactants possessing identical hydrophobic chains but different ionic head groups (cationic, anionic, zwitterionic) were synthesized, and their aqueous solution properties were examined. The results showed that the surface activities of gemini surfactants are superior to those of corresponding conventional monomeric surfactants, and molecular arrangements of gemini surfactants at the air-water interface are tighter than those of corresponding conventional surfactants. It was also found that zwitterionic gemini surfactant possesses the highest surface activity among the three surfactants. The behavior at the air-water interface is closely related to the molecular structural features of surfactants, which provide an indication for synthesizing highly-efficient surfactants.      

Macromolecular surfactants for miniemulsion polymerization

The use of polymeric surfactants as stabilizers in miniemulsion polymerization was reviewed. The structural characteristics of reported polymeric surfactants were detailed and compared. The concept of multi-functional polymeric surfactants was evidenced. The specificities brought by polymeric surfactants in the process of miniemulsion polymerization in comparison to molecular surfactants were analysed for the stability of the initial monomer emulsion, polymerization kinetics and characteristics of the obtained latexes. The contribution of polymeric surfactants to the control of the characteristics of the obtained nanoparticles was detailed with regard to the nature of the core material and to the surface coverage. Polymeric surfactants can be seen as powerful tools for the design of original nanoparticles. On the basis of the available data, possible research topics are suggested.     

Oil Solubilization Capacity,Liquid Crystalline Properties,and Antibacterial Activity of Alkanolamine‐Based Novel Cationic Surfactants

A series of monomeric and dimeric cationic surfactants with tuned polarity was synthesized. Oil solubilization capacity, thermotropic liquid crystalline properties, and minimum inhibitory concentration (MIC) of novel hydroxylated cationic surfactants using selected gram positive and gram negative bacteria were examined. Antibacterial activity and the propensity of gemini surfactants for oil solubilization were observed to be better than those of corresponding monomeric surfactants. Pseudo ternary phase diagrams for these surfactants, methyl methacrylate (MMA), and water clearly showed, that microemulsions can be easily formulated with all these surfactants. Solubilization and foam studies of mixed surfactant systems were also examined. Molecular architecture like the tail length, head group area, and presence of ethanolic goups in the surfactant affect the performance properties. Unlike conventional gemini surfactants the synthesized gemini surfactants also show thermotropic liquid crystalline properties (smectic‐A, L_α phase).     

Synthesis and properties of novel cationic gemini surfactants with adamantane spacer

Novel quaternary ammonium cationic gemini surfactants, with two hydrocarbon chains and an adamantane core, were designed and synthesized by three-step reactions from adamantane. The structure of obtained surfactants were confirmed by 1H NMR, FTIR and elements analysis and the surface properties of these surfactants were also studied by surface tension measurements. These target surfactants exhibit much lower critical micelle concentrations （CMC） and higher efficiency in lowering the surface tension of water than typical surfactants.     

Synthesis of novel quaternary ammonium surfactants containing adamantane

A series of novel quaternary ammonium surfactants containing adamantane were designed and synthesized from 1-adamantanecarboxylic acid.The structures of target surfactants were confirmed by]H NMR,elements analysis and FTIR.Surface properties of these surfactants were investigated.Due to the lipophilicity of adamantane,the critical micelle concentration（CMC） and C₂₀ values of the synthesized quaternary ammonium surfactants are lower than that of conventional quaternary ammonium surfactants.