含三嗪环阴离子Gemini表面活性剂的性能研究

研究了含三嗪环阴离子Gemini表面活性剂增溶、流变、溶致液晶、囊泡等性能。结果表明:增溶量随Gemini表面活性水基和联接基长度)对其水溶液的黏度有相同的影响;C6-2-C6、C8-2-C8、C8-3-C8、C8-4-C8、C8-6-C8、C12-2-C12在质量分数剂疏水链长度的增长而增大,C8-n-C8(n=23,4,6,)的增溶量随联接基长度增加而增加,C12-2-C12与SDS的复配体系比SDS的增溶量大,C12-2-C12与CTAB的复配体系比这2种表面活性剂单独使用时的增溶量小;Gemini表面活性剂溶液分子结构(疏分别为42.3%,37.8%,33.5%,30.4%,27.6%2,0.3%时均产生层状的溶致液晶;0.01 mol/L的单一Gemini表面活性剂水溶液均不能形成囊泡,而当n(C12-2-C12)∶n(CATB)为8∶2或9∶1时,复配体系的水溶液形成了大量的囊泡结构。     

羟基和酯基型Gemini双季铵盐表面活性剂在煤沥青表面的润湿特性

以自制的羟基和酯基型Gemini双季铵盐表面活性剂为研究对象,在考察其表面活性的基础上,进一步研究了表面活性剂在煤沥青表面的润湿性。研究表明,羟基型Gemini表面活性剂在煤沥青表面的接触角随疏水链长度的增长呈先减小后增大趋势,其中C_(12)-OH在煤沥青表面的润湿效果最好;对于m-n-m酯基型Gemini表面活性剂而言,接触角随疏水链长度的增长而降低。当疏水链长度一定时,m-6-m在煤沥青表面的润湿效果比m-2-m好。在一定浓度范围内,C_(10)-OH、C_(12)-OH和12-2-12 3种Gemini表面活性剂的表面张力与其在煤沥青表面黏附张力呈线性关系。煤沥青表面的Zeta电位随Gemini表面活性剂浓度的增大呈先增大后趋于平稳的趋势。     

磺酸盐型Gemini表面活性剂复配体系的黏度性质研究

对以溴代十四烷、乙二胺和1,3-丙磺内酯为原料合成的磺酸盐型Gemini表面活性剂的表面活性进行了评价。主要研究了不同碳链长度的季铵盐、无机盐和有机盐的加入,剪切时间以及温度对上述表面活性剂体系黏度性质的影响。结果表明,磺酸盐型Gemini表面活性剂的临界胶束浓度比相应的单链表面活性剂低1~2个数量级;当向质量分数为1%的磺酸盐型Gemini表面活性剂中加入季铵盐时,复配体系的黏度先增加后减少,且季铵盐的碳链越长,增黏效果越明显,复配体系的黏度最大可达245.5 m Pa·s,碳链的增长有助于蠕虫状胶束的形成;在磺酸盐型Gemini表面活性剂和十六烷基三甲基溴化铵(CTAB)的复配体系中,随着KCl,Na Cl以及水杨酸钠质量分数的增加,复配体系的黏度先增加后减少,其中KCl的增黏效果最为显著,当KCl的质量分数为0.12%,复配体系的黏度达到最大,为430.2 m Pa·s;在磺酸盐型Gemini表面活性剂/CTAB/KCl的复配体系中,随着剪切时间和温度的增加复配体系的黏度逐渐降低。     

非水相溶致液晶形成的研究进展

随着溶致液晶在生物仿生、功能材料、化学工业、医药学、石油工业、日用化妆品等领域的应用,人们对构建非水相溶致液晶的研究也日益深入。通过介绍表面活性剂聚集体溶致液晶形成的基础理论,综述了表面活性剂在直链醇(甘油、乙二醇等)、有机胺化合物(甲酰胺、N-甲基甲酰胺等)、离子液体等非水溶剂中溶致液晶的形成、表征手段和应用,并对该领域的发展趋势进行了展望。     

羟基和酯基型Gemini双季铵盐表面活性剂在煤沥青表面的润湿特性

以自制的羟基和酯基型Gemini双季铵盐表面活性剂为研究对象,在考察其表面活性的基础上,进一步研究了表面活性剂在煤沥青表面的润湿性。研究表明,羟基型Gemini表面活性剂在煤沥青表面的接触角随疏水链长度的增长呈先减小后增大趋势,其中C₁₂-OH在煤沥青表面的润湿效果最好;对于m-n-m酯基型Gemini表面活性剂而言,接触角随疏水链长度的增长而降低。当疏水链长度一定时,m-6-m在煤沥青表面的润湿效果比m-2-m好。在一定浓度范围内,C₁₀-OH、C₁₂-OH和12-2-123种Gemini表面活性剂的表面张力与其在煤沥青表面黏附张力呈线性关系。煤沥青表面的Zeta电位随Gemini表面活性剂浓度的增大呈先增大后趋于平稳的趋势。     

Gemini表面活性剂/醇/正辛烷/盐水体系微乳液的研究

以壬基酚为原料在催化剂存在下与二溴烷烃作用生成双醚,然后磺化,合成了一类Gemini阴离子表面活性剂,用悬滴法测定了其油水界面张力,结果表明,Gemini表面活性剂可使油水界面张力降低到 10-3mN/m。研究了Gemini表面活性剂 /醇 /正辛烷 /盐水体系的微乳液相行为,通过拟三元相图的方法确定了助表面活性剂醇的种类,实验结果表明,链长的比链短的醇具有更好的助活作用。通过正交实验方法得到了形成中相微乳液的最佳组成:w(GeminiD) =0 1%;w(n C6H13OH) =4 0%;w(NaCl) =1 5%。     

反离子盐(溴化钾)对不同疏水链长的Gemini阳离子表面活性剂表/界面活性的影响

以1,4-二溴-2-丁烯为连接基团,脂肪酰胺丙基二甲胺(PKO-12,PKO-16,PKO-18)为疏水链合成了一类连接基团为不饱和链的酰胺基Gemini表面活性剂(GS-12,GS-16,GS-18)。通过FTIR和¹H NMR对产物进行结构表征,并对其Krafft温度、溴化钾耐受性进行了测试。研究了KBr浓度对表面活性剂的表/界面活性以及在石蜡膜上的润湿性能的影响。结果表明,成功制备3种酰胺基Gemini表面活性剂GS-12,GS-16,GS-18,且其Krafft温度随链长的增加而升高。GS-12的Krafft温度低于0℃,GS-16,GS-18的Krafft温度分别为27,27.5℃。在KBr浓度0～100 mmol/L范围内,随着KBr盐浓度的增加表/界面张力显著降低。此外,在一定KBr浓度范围内,随着盐浓度的增加,润湿性能增强。     

Gemini型表面活性剂改性蒙脱土的制备与应用研究进展

总结了阳离子Gemini表面活性剂改性蒙脱土的制备方法,列出了Gemini表面活性剂在层间展现不同的排列方式,描述了含不同烷基链、间隔基、头基和官能团的Gemini表面活性剂对有机蒙脱土的影响,并对Gemini表面活性剂改性的有机蒙脱土应用研究进行了展望。     

双子表面活性剂疏水链对油水界面行为的影响

双子表面活性剂(Gemini surfactants)已经被认为是传统的单子表面活性剂的新型替代品。然而,双子表面活性剂对油水界面影响的微观机制还没有被充分理解,通过构建了具有不同疏水链长度的双子表面活性剂并利用耗散粒子动力学(DPD)模拟研究了双子表面活性剂对油水界面行为的影响,研究结果表明,双子表面活性剂的表面活性随着疏水链长度的增加而增加,这也促使油水界面从层状转变为乳状液滴形态。温度的上升有利于降低油水界面张力使混合体系转变为乳液状态。表面活性剂疏水尾链和油珠之间的相互作用随着疏水尾链长度的增加而增加。     

非离子型Gemini表面活性剂的性质

Gemini表面活性剂具有的优良表面活性,使之有望作为三次采油用的表面活性剂。用界面张力仪及HAAKERS600流变仪研究了非离子型Gemini表面活性剂的表面活性及流变特性。结果表明,25℃下,氧乙基数(EO数)分别为8,10,12的3种非离子型Gemini表面活性剂8-NP-8、10-NP-10及12-NP-12的临界胶束浓度(cmc)值分别为:0.99,0.15和0.032 mmol/L;非离子型Gemini表面活性剂的表面活性及cmc值受电解质的影响较小;氧乙基数为12的非离子型Gemini表面活性剂可以使亲水及亲油固体表面的接触角明显降低,水润湿性增强;非离子型Gemini表面活性剂溶液的粘度随剪切速率增加基本保持不变,呈现出牛顿流体的特性。     

离子液体表面活性剂的合成与应用(III)——离子液体表面活性剂的物化性能

重点介绍了离子液体表面活性剂的熔点与结构的关系。阳离子母体结构越不对称熔点越低,烷基链长增加熔点稍有提高;对阴离子型离子液体表面活性剂,阳离子的半径越大,其熔点越低;双子和Bola型离子液体表面活性剂比单疏水基离子液体表面活性剂的熔点高。室温呈液态的离子液体表面活性剂一般为黏稠液体,密度比一般有机溶剂大,在1 g/cm3左右,其表面张力为25~35 mN/m。     

Behaviour of the miscibility of poly(ethylene oxide)/liquid crystal blends

The microscopic behaviour of blends of poly(ethylene oxide) with two different low molecular weight liquid crystals (LC) was studied in order to evaluate miscibility. One of the liquid crystal components had a phase transition temperature lower than the melting temperature of poly(ethylene oxide) (PEO), and the other a higher value. The low molecular weight liquid crystal components were 4-cyano-4′-n-heptylbiphenyl (7CB) and p-cyanophenyl p-pentyloxybenzoate (pCP). Thermal analysis and polarized optical and scanning electron microscopy were employed. The melting temperature (T_m) depression of PEO increased with LC content in the blend, suggesting that the PEO was miscible with both liquid crystals in the isotropic phase. The spherulitic structural morphology of the semicrystalline components is affected by the presence of liquid crystals. © 1998 SCI.     

季铵盐型Gemini表面活性剂气液界面行为研究

合成了不溶于水的季铵盐型Gemini表面活性剂18-s-18(=3,4,6,8,10,12),研究了联结基团长度对Gemini表面活性剂在气液界面上的性质的影响.结果表明:对不同长度的联结基团,表面压-分子面积曲线很相似;极限面积在s≤6时几乎成直线快速增加,并在s=10时达到最大值,s>10时稍微下降.     

离子液体表面活性剂的合成与应用(Ⅱ)——离子液体表面活性剂的合成

按照离子液体表面活性剂的种类,分别介绍了不同类型离子液体表面活性剂的合成方法。阳离子型离子液体表面活性剂可以采用直接季铵化法、复分解法和离子交换法合成;阴离子型离子液体表面活性剂是采用传统阴离子表面活性剂与离子液体在有机溶剂或水/有机溶剂中复分解反应完成的;两性离子液体表面活性剂通常采用直接季铵化法合成;双子和Bola型离子液体表面活性剂与传统双子和Bola型表面活性剂的合成方法相似;微波和超声等新的辅助合成方法将明显促进离子液体表面活性剂的合成。     

Molecular dynamics simulation on the structure–activity relationship between the Gemini surfactant and foam properties

The structure–activity relationship between the molecular structure of Gemini surfactants and foam properties has not yet been deeply revealed. In this study, we clarified for the first time the structure–activity relationship between foam properties and molecular structure of Gemini surfactant by discussing the variation characteristics of parameters such as free energy of interface formation, radial distribution function, and mean square displacement calculated by molecular simulation method. The research results show that (1) the Gemini surfactant with the sulfonic acid head group has the most excellent foam properties; (2) the foam properties increase monotonously with the increase of the hydrophobic tail chain length; (3) the foam properties decrease monotonously with the increase of the spacer group length. It is hoped that this article can further broaden the application range of surfactants as foaming agents in industrial fields such as oil and gas exploitation.     

Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1∶1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.     

Preparation of polymethacrylate-based side-chain liquid crystalline polymers with various lengths of aliphatic spacer and their electrorheology

Three kinds of side-chain liquid crystal polymers (SCLCPs) were prepared in which the lengths of the flexible aliphatic spacer were 6, 8, and 12 methylene units. The SCLCPs consisted of a polymethacrylate backbone carrying cyanobiphenyl mesogenic groups as side chains. All the polymers exhibited liquid crystalline behavior of smectic A phase. The glass transition temperature decreased with increasing aliphatic spacer length. Electrorheological (ER) suspensions were prepared by dispersing the SCLCP particles in silicone oil and their ER effects were investigated. The ER response increased with increasing aliphatic spacer length, indicating that the spacer length between the polymethacrylate backbone and polar mesogenic groups influenced the ER behavior.     

Effects of Spacers on Surface Activities and Aggregation Properties of Anionic Gemini Surfactants

This present article employs four anionic Gemini surfactants with different spacer groups and investigates their physicochemical and aggregation properties. The critical micelle concentration (CMC), surface tension at CMC (γ_CMC) and C ₂₀ of these surfactants have been investigated using the du Nouy ring method. The aggregation number (N) was determined with intrinsic fluorescence quenching method using pyrene as a fluorescence probe and benzophenone as a quencher. Results show that these anionic Gemini surfactants have lower CMC and C ₂₀ values compared with those conventional ones and show higher surface activity. As expected, the spacer plays an important role in the aggregation properties of Gemini surfactants. Under experimental conditions, Gemini B–D with an alkoxylated group as spacer has a lower CMC and a higher aggregation number than Gemini A with methylene as spacer. For Gemini B–D, the CMC and aggregation number values decrease with the increasing flexible spacer length. The micropolarity also affects the aggregation of the present anionic Gemini surfactants. The micropolarity of micelle becomes low when the concentration of surfactants increases. Aggregation numbers of surfactants increase and fluorescence intensities decrease with the increasing concentration of NaCl. These results will help us to understand the relationship between the architectures of Gemini surfactants and their various properties in aqueous solution. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.