Review on Anionic/Cationic Surfactant Mixtures

It is commonly known that cationic and anionic surfactants cannot be mixed without the risk of precipitation or instability. However, many studies have shown that not only is it possible to combine cationic and anionic surfactants, but also that this combination can present synergic properties. Mixtures of anionic and cationic surfactants have many unique properties that can be very useful when used properly. The aim of this report is to present relevant information concerning the interaction between anionic and cationic surfactants. A bibliographic review on anionic/cationic mixtures is presented here in order to better understand their properties and possible synergic effects, as this is of practical importance for the chemical industry.

Interactions between Anionic Polyacrylamide and Cationic Gemini/Conventional Surfactants

The interaction of anionic polymer polyacrylamide and cationic Gemini surfactants, namely: α,ω-bis(hexadecyldimethylammonium)alkane dibromides, (16-s-16), s = 5, 6 and their conventional counterpart cetyltrimethylammonium bromide (CTAB) has been investigated by electrical conductivity, rheology, and scanning electron microscopy (SEM) techniques. Stronger interaction of Gemini surfactants in comparison to their conventional counterpart CTAB was observed from conductivity studies, while viscosity studies show that the interaction is quite significant with Gemini surfactants. The thermodynamic parameters for interactions show feasibility of interaction between the polymer and surfactant. SEM results support the viscosity data.     

一些阴离子／阳离子二元混合体系的增溶行为

研究了十二烷基聚氧乙烯（约含3个EO基团）硫酸三乙醇铵（TADPS）分别与十六烷基三甲基溴化铵（CTABr）、氯化十六烷基毗院（CPCI）以及氯化十二烷基吡啶（DPCI）的二元混合体系对正庚烷、正辛醇以及甲苯的饱和增溶行为。结果表明,混合体系在增溶方面的协同效应取决于增港物的极性或增港物在胶团中的位置．对增溶于胶团内核的非极性正庚烷,TAPDS／CTABr体系显示出较强的实际正协同效应,最大添加浓度（MAC）可用Nishikido的阴离子-阳离子复合物理想增港模型来预测;对既可增溶于胶团的内核,又可增溶于胶团栅栏中的微极性的甲苯,三个混合体系皆表现出实际的正协同效应;但对增溶于胶团栅栏,与表面活性剂形成混合胶团的两亲物质正辛醇,TAD－PA／CTABr体系显示出负协同效应,并且增溶物在胶团相和水相中的分布系数符合Treiner的非理想增溶模型。这些结果表明,阴离子／阳离子混合体系在胶团强化超滤（MEUF）技术中具有潜在的应用前景。     

阴离子／阳离子混合表面活性剂体系的协同效应及其应用

综述了阴离子／ 阳离子混合表面活性剂体系在表面张力降低的效率、效能、混合胶束形成及其增溶能力等方面的协同效应以及相行为方面的研究结果。为针对不同应用场合的阴／ 阳离子混合体系的选择提供了理论依据     

阴-阳离子捕收剂浮选铁尾矿中低品位云母的试验研究

云母是一种重要的非金属矿物资源,以云南铁尾矿中的低品位云母为研究对象,通过化学分析、X射线衍射(XRD)分析和矿物参数自动定量分析(MLA)对原样进行了工艺矿物学研究,白云母是主要的目的矿物,黑云母少量存在,脉石矿物主要为石英、钠长石、赤铁矿和绿泥石.本文重点研究了不同阴-阳离子捕收剂组合、阴-阳离子捕收剂的配比和捕收剂用量等对云母浮选的影响,十二烷基磺酸钠(SDS)和十二胺(DDA)为最佳的捕收剂组合,其最佳的用量配比为2∶1、最佳用量分别为40 g/t和20 g/t.再磨能有效提升粗精矿的回收率,最佳的再磨细度为-45 μm占90％.最终,采用一粗一扫五精的浮选闭路流程,可获得钾的品位和回收率分别为7.82％和64.74％的云母精矿.XRD及化学分析显示,云母在精矿中得到了较好的富集.     

Cationic Antimicrobial Polymers and Their Assemblies

Cationic compounds are promising candidates for development of antimicrobial agents. Positive charges attached to surfaces, particles, polymers, peptides or bilayers have been used as antimicrobial agents by themselves or in sophisticated formulations. The main positively charged moieties in these natural or synthetic structures are quaternary ammonium groups, resulting in quaternary ammonium compounds (QACs). The advantage of amphiphilic cationic polymers when compared to small amphiphilic molecules is their enhanced microbicidal activity. Besides, many of these polymeric structures also show low toxicity to human cells; a major requirement for biomedical applications. Determination of the specific elements in polymers, which affect their antimicrobial activity, has been previously difficult due to broad molecular weight distributions and random sequences characteristic of radical polymerization. With the advances in polymerization control, selection of well defined polymers and structures are allowing greater insight into their structure-antimicrobial activity relationship. On the other hand, antimicrobial polymers grafted or self-assembled to inert or non inert vehicles can yield hybrid antimicrobial nanostructures or films, which can act as antimicrobials by themselves or deliver bioactive molecules for a variety of applications, such as wound dressing, photodynamic antimicrobial therapy, food packing and preservation and antifouling applications.     

Microstructure and Phase Behavior of Cationic Gemini/Anionic Polyelectrolyte/Water Ternary System

The microstructure of cationic gemini surfactant 1,6-bis(dodecyldimethylammonium) hexane dibromide [C12H25(CH3)2N-(CH2)6-N(CH3)2C12H25×2Br] (12-6-12×2Br-) and oppositely charged polyelectrolyte poly(acrylic acid, sodium salt) (NaPA) in aqueous solution has been studied by using fluorescence, conductivity measurement, freeze-etching and TEM. The data obtained from fluorescence and conductivity measurement show that micelle-like or complex can form between the gemini surfactant (12-6-12×2Br-) and polyelectrolyte NaPA due to the static electric interaction and hydrophobic forces. Through freeze-etching and TEM, the microstructure of the mixture solution has been studied, which is consistent with the result from micropolarity. Comparing the fluorescence spectrum of system of dodecyltrimethylammonium bromide (DTAB) and NaPA with that of system of gemini surfactant (12-6-12×2Br-) and NaPA, it can be found that the interaction between gemini surfactant (12-6-12×2Br-) and NaPA is stronger than that between DTAB and NaPA. And the phase behavior of (12-6-12×2Br-) and NaPA in aqueous solution has also been detected. It can be shown that the precipitate will transform into gel in higher NaPA concentration.     

高碳链正负离子表面活性剂复配溶液的表面物理化学性质研究

研究了负离子表面活性剂C12SNa同正离子表面活性剂（C18H37）2N（CH3）3Cl、C16H33N（CH3）3Cl复配溶液的表面物理化学性质,结果表明复配液具有比单一表面活性剂更高的表面活性,且无论正负离子表面活性剂复配比例如何,表面的吸附量与1:1复配液吸附量相似,即吸附量R^ 同R^-比例为1:1左右。     

Tailoring Chitosan/LTA Zeolite Hybrid Aerogels for Anionic and Cationic Dye Adsorption

Chitosan (CS) is largely employed in environmental applications as an adsorbent of anionic dyes, due to the presence in its chemical structure of amine groups that, if protonated, act as adsorbing sites for negatively charged molecules. Efficient adsorption of both cationic and anionic dyes is thus not achievable with a pristine chitosan adsorbent, but it requires the combination of two or more components. Here, we show that simultaneous adsorption of cationic and anionic dyes can be obtained by embedding Linde Type A (LTA) zeolite particles in a crosslinked CS-based aerogel. In order to optimize dye removal ability of the hybrid aerogel, we target the crosslinker concentration so that crosslinking is mainly activated during the thermal treatment after the fast freezing of the CS/LTA mixture. The adsorption of isotherms is obtained for different CS/LTA weight ratios and for different types of anionic and cationic dyes. Irrespective of the formulation, the Langmuir model was found to accurately describe the adsorption isotherms. The optimal tradeoff in the adsorption behavior was obtained with the CS/LTA aerogel (1:1 weight ratio), for which the maximum uptake of indigo carmine (anionic dye) and rhodamine 6G (cationic dye) is 103 and 43 mg g⁻¹, respectively. The behavior observed for the adsorption capacity and energy cannot be rationalized as a pure superposition of the two components, but suggests that reciprocal steric effects, chemical heterogeneity, and molecular interactions between CS and LTA zeolite particles play an important role.     

阴离子型水性聚氨酯和阳离子型水性聚氨酯的合成及分析

以甲苯二异氰酸酯（TDI）和聚酯二醇等为基本原料,在NCO／OH比例及反应物量相同的情况下,分别合成了阴离子型水性聚氨酯和阳离子型水性聚氨酯。对它们进行了红外光谱分析、热重分析、粒径分析、吸水率测定和力学测试。结果表明：合成的阴离子水性聚氨酯无残余的-NCO,粒径、吸水率小于阳离子型水性聚氨酯,拉伸强度、断裂伸长率大于阳离子型水性聚氨酯,耐水性强于阳离子型水性聚氨酯。     

阴/阳离子表面活性剂复配改性粘土/橡胶纳米复合材料的结构与性能

采用阴离子表面改性剂十二烷基磺酸钠(SDS)与阳离子表面改性剂十八烷基三甲基溴化铵(STAB)复配改性粘土,制备有机粘土/橡胶纳米复合材料,考察其结构和性能。结果表明:当SDS/STAB质量比为2/4时,有机粘土/丁腈橡胶(NBR)纳米复合材料的综合物理性能最优,STAB的有机阳离子取代无机粘土层间可交换的阳离子,SDS通过碳-氢键与无机粘土层间非极性较强的质点发生范德华力及离子静电吸附作用,获得晶层间距更大的有机粘土;与非极性的丁苯橡胶和天然橡胶相比,极性的NBR使粘土的远程聚集趋势减小和界面吸附作用增强,相应复合材料的物理性能增幅更大。     

阴阳离子表面活性剂自发形成囊泡的影响因素

在阴阳离子表面活性剂(SDS/CTAB)复配体系中自发形成囊泡。通过TEM、Zeta粒径分析和表面张力测定等手段进行表征,结果表明浓度、温度、溶剂、pH值等因素对囊泡稳定性有影响,在T=40℃,40%的乙醇为溶剂,调控pH=5,复配浓度在2×10-3mol/L条件下形成的囊泡稳定性最佳。     

阳离子聚电解质与阴离子表面活性剂大分子复合物的形成及其溶液流变性能

将不同阳离子电荷度的丙烯酰胺-丙烯酰氧乙基三甲基氯化铵共聚物与反电性阴离子十二烷基硫酸钠复合,由电导率测定发现两者依靠静电引力结合的大分子复合物存在着非电荷化学计量比关系。低于临界沉淀浓度时,大分子复合物能够保持分散溶解状态,溶液属于假塑性流体。并且分子复合作用使溶液的抗剪切稀释能力增强。     

Properties of a Binary System Containing Anionic and Cationic Gemini Surfactants

Surface tension, fluorescence, and dynamic light scattering were used to investigate the properties of a binary surfactant system comprising an anionic gemini surfactant (DLMC) and cationic gemini surfactant (II‐12‐EO₂). Surface tension measurements afforded the critical micelle concentration (cmc) of the mixture and the values are all lower than those of pure constituent surfactants. For the mixtures of II‐12‐EO₂/DLMC, the micelle aggregation number decreases with the increase of II‐12‐EO₂, and the micropolarity of the micelle is lowest when the molar fraction of II‐12‐EO₂ is 0.5; the hydrodynamic radius (R_h) of the mixed micelle first increases and then decreases with the addition of II‐12‐EO₂, and larger micelles are obtained when the molar fraction of II‐12‐EO₂ is 0.5 or 0.7.     

Photoimmunotherapy Using Cationic and Anionic Photosensitizer-Antibody Conjugates against HIV Env-Expressing Cells

Different therapeutic strategies have been investigated to target and eliminate HIV-1-infected cells by using armed antibodies specific to viral proteins, with varying degrees of success. Herein, we propose a new strategy by combining photodynamic therapy (PDT) with HIV Env-targeted immunotherapy, and refer to it as HIV photoimmunotherapy (PIT). A human anti-gp41 antibody (7B2) was conjugated to two photosensitizers (PSs) with different charges through different linking strategies; “Click” conjugation by using an azide-bearing porphyrin attached via a disulfide bridge linker with a drug-to-antibody ratio (DAR) of exactly 4, and “Lysine” conjugation by using phthalocyanine IRDye 700DX dye with average DARs of 2.1, 3.0 and 4.4. These photo-immunoconjugates (PICs) were compared via biochemical and immunological characterizations regarding the dosimetry, solubility, and cell targeting. Photo-induced cytotoxicity of the PICs were compared using assays for apoptosis, reactive oxygen species (ROS), photo-cytotoxicity, and confocal microscopy. Targeted phototoxicity seems to be primarily dependent on the binding of PS-antibody to the HIV antigen on the cell membrane, whilst being independent of the PS type. This is the first report of the application of PIT for HIV immunotherapy by killing HIV Env-expressing cells.     

Synergism and Performance for Systems Containing Binary Mixtures of Anionic/Cationic Surfactants for Enhanced Oil Recovery

The surfactant structure–performance relationship and application properties in enhanced oil recovery (EOR) for binary mixtures of anionic and cationic surfactants are presented and discussed. A polyoxyethylene ether carboxylate anionic surfactant was blended with a quaternary ammonium chloride cationic surfactant and tested for a high-temperature, low-salinity, and high-hardness condition as found in an oil reservoir. These mixtures were tailored by phase behavior tests to form optimal microemulsions with normal octane (n-C8) and crude oil having an API gravity of 48.05°. The ethoxy number of the polyoxyethylene carboxylate anionic surfactant and the chain length of the cationic surfactant were tuned to find an optimal surfactant blend. Interfacial tensions with n-C8 and with crude oil were measured. Synergism between anionic and cationic surfactants was indicated by surface tension measurement, CMC determination, calculation of surface excess concentrations and area per molecule of individual surfactants and their mixtures. Molecular interactions of anionic and cationic surfactants in mixed monolayers and aggregates were calculated by using regular solution theory to find molecular interaction parameters β ^σ and β ^M . Morphologies of surfactant solutions were studied by cryogenic TEM. The use of binary mixtures of anionic/cationic surfactants significantly broadens the scope of application for conventional chemical EOR methods.     

含环戊二烯络铁基团苯乙烯聚合物的合成和表征

介绍了含环戊二烯络铁基团苯乙烯聚合物的合成,并用核磁共振仪、红外光谱仪、差热分析仪对该类聚合物的结构、性质进行了研究和表征.实验表明在丙酮溶剂中,以偶氮二异丁腈为引发剂,含环戊二烯络铁基团苯乙烯在(60士5)℃进行均聚或与甲基苯乙烯共聚收率高.用凝胶色谱仪分析,聚合物分子量较大,分子量分布范围(PDI)小于3.0.     

Adsorption Behavior of Cationic and Anionic Dyes onto Acid Treated Coconut Coir

The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) from aqueous solutions by acid treated coconut coir was investigated under laboratory conditions to assess its potential in removing cationic and anionic dyes. The acid treated coconut coir exhibited better adsorption capacity in cationic dye MB than anionic dye AO7 and the data obtained can be well described by both Langmuir and Freundlich isotherm models. According to the Langmuir isotherm model, the maximum adsorption capacities of MB and AO7 onto acid treated coconut coir were 121 mg/g and 10 mg/g, respectively. The adsorption behavior of MB and AO7 onto acid treated coconut coir was analyzed with first-order Lagergren model and pseudo-second order model.     

The Effect of Ethanol on Nanostructures of Mixed Cationic and Anionic Surfactants

Micellization of tetradecyl trimethyl ammonium bromide (TTAB) and sodium dodecyl sulfate (SDS) in water–ethanol (ET) micellar solutions, with the weight percent of ET changing within the range 0–30, was studied by means of surface tension and conductivity measurements. Surface tension measurements also provided information about the dependence of the surface excess concentration, the minimum area per surfactant molecule, and the standard Gibbs energy of adsorption on the added weight percent of the organic solvent. Information about the degree of counterion dissociation and phase transition was obtained through conductivity measurements. Cyclic voltammetry (CV) and dynamic light scattering (DLS) was also employed to investigate the mixed micellar behavior of the binary mixtures. It was shown that an excess of cationic surfactant and ET resulted in a phase transition of vesicles and large micelles to mixed micelles. The regular solution theory approximation was used to determine various micellar parameters of ideal systems. The regular solution interaction parameter (β) suggests that the formation of mixed micelles is due to the synergistic interactions in the case of TTAB/SDS systems and becomes affected by the water/ET ratio.