阴离子表面活性剂－溴化十二烷基二甲基苄基铵－溴百里酚蓝显色反应的分光光度法研究

本文研究了溴化十二烷基二甲基苄基铵－溴百里酚蓝与阴离子表面活性剂显色反应的适宜条件。结果表明，在ｐＨ７．４～８．２范围内阴离子表面活性剂与题示试剂形成１：２：１的绿色离子缔合物，其最大吸收峰位于６１４ｎｍ处。表现摩尔吸光系数分别为：＝３．９９×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）；＝３．７０×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）；＝１．７１×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。ＳＤＢＳ在０～１９５μｇ／１０ｍＬ，ＳＤＳ在０～１５８μｇ／１０ｍＬ，ＳＬＳ在０～６０μｇ／１０ｍＬ范围内遵守比耳定律。该法用于河水和生活废水中阴离子表面活性剂测定，结果满意。     

荧光探针法测定甜菜碱cmc的研究

荧光探针法测定甜菜碱ｃｍｃ的研究任学贞，李干佐，王弘立，翟立民，隋卫平，徐欣艳（山东大学化学系，济南，２５０１００）关键词甜菜碱，芘，临界胶束浓度Ｅｋｗａｌｌ等［１］发现，表面活性剂的溶液能够增溶多环芳烃并发射较强的荧光．在常用的测定表面活性剂临界胶...     

阴离子表面活性剂—溴化十二烷基二甲基苄基铵—溴百里酚蓝显色反应…

本文研究了溴化十二烷基二甲基苄铵－溴百里酚蓝与阴离子表面活性剂显色反应的适宜条件结果表明，在ｐＨ７．４～８．２范围内阴离子表面活性剂与题示试剂形成１：２：１的绿色离子缔合物，其最大吸收峰位于６１４ｎｍ处。表观摩尔吸光系数分别为ε＾ＳＤＢＳ６１４＝３．９９×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１；ε＾ＳＤＳ６１４＝３．７０×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，ε＾ＳＬＳ６１４＝１．７１×１０＾４Ｌ．     

微乳液法制备超细包裹型铁粉

应用Ｗ／Ｏ型微乳流法制备了纳米量级包裹型超细铁粉,由ＸＲＤ、ＳＥＭ、ＴＥＭ和ＩＲ谱测试表明：它属于表面活性剂包裹型超细微粒。平均粒径约１２０ｎｍ,微粒的密度为３．００ｇ／ｃｍ＾３。比饱和磁化强度σｓ＝９２．４Ａｍ＾２／ｋｇ,矫顽力Ｈｅ＝４３（Ｏｅ）,剩磁ｒ＝３．８９Ａｍ＾２／ｋｇ。将其用于制备磁流变液（ＭＲＦ）,具有良好的磁流变（ＭＲ）性能和优良的沉降稳定性。     

1-(4-硝基苯基)-3-[4-(苯基偶氮)苯基]-三氮烯-溴化十六烷基三甲铵-阴离子表面活性剂显色反应的研究及应用

在三乙醇胺存在下,１－（４－硝基苯基）－３－［４－（苯基偶氮）苯基］－三氮烯（Ｃａｄｉｏｎ）与溴化十六烷基三甲铵（ＣＴＭＡＢ）和阴离子表面活性剂（ＡＳ）形成红色配合物,其最大吸收位于５５０ｎｍ。改变阴离子表面活性剂十二烷基苯磺酸钠、十二烷基磺酸钠、十二烷基硫酸钠时,有色配合物的表观摩尔吸光系数ε５５０分别为３．０２×１０４、２．１３×１０４、２．９４×１０４（Ｌｍｏｌ－１ｃｍ－１）,阴离子表面活性剂服从比尔定律的范围分别为０～４．１８ｍｇ／Ｌ,０～２．１８ｍｇ／Ｌ,０～３．４６ｍｇ／Ｌ。方法用于测定环境水样中阴离子表面活性剂,结果满意     

光谱与停流荧光法研究肌红蛋白及其突变体D60K与表面活性剂的相互作用

用停流荧光法、紫外光谱法、荧光光谱法和圆二色(CD)光谱法研究了肌红蛋白(Mb)及其突变体Mb(D60K)分别与两种表面活性剂的相互作用.停流荧光数据表明不同浓度的十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)与Mb及Mb(D60K)相互作用均为(准)一级反应,虽然Mb(D60K)只是将肌红蛋白表面的60位天冬氨酸突变为赖氨酸,但二者性质差异显著,说明60位氨基酸对蛋白质性质影响较大.紫外、荧光与圆二色谱的结果也表明在上述表面活性剂作用下肌红蛋白及其突变体结构与功能均发生变化,其适应性和稳定性有一定差异.综合数据分析得知,肌红蛋白突变体D60K在表面活性剂溶液中性质更加稳定.     

铵基乙酸盐型两性表面活性剂的合成

以月桂酸、硬酯酸和羟乙基乙二胺为原料，经环化、还原和季铵化合成了４种新化合物，对其中２种按基乙酸盐两性表面活性剂的表面张力、临界胶束浓度（ｃｍｃ）和泡沫性能做了测定。     

表面活性剂对完全液相法制Cu-Zn-Al浆状催化剂结构和性能的影响

采用完全液相法制备了Cu-Zn-Al双功能浆状催化剂, 利用不同类型表面活性剂对其进行了修饰和改性. 通过N2气吸附、XRD和XPS等方法考察了表面活性剂类型对催化剂织构、物相以及表面性质的影响, 采用浆态床反应装置对其合成气一步法制备二甲醚的催化活性进行了评价, 讨论了催化剂结构与性能的关系. 结果表明, 表面活性剂主要是通过与活性金属的作用调节催化剂的表面性质、孔结构、相结构以及晶粒大小, 进而影响催化剂的催化活性; 非离子表面活性剂总体上对催化剂的性能有促进作用, 阳离子表面活性剂和阴离子表面活性剂对催化剂性能存在不利影响; 表面活性剂与活性金属作用的强弱是影响性能的关键.     

表面张力法和电导法对比测定表面活性剂临界胶束浓度*

通过比较表面张力法和电导法测定阴离子表面活性剂十二烷基硫酸钠(SDS)和非离子表面活性剂辛基酚聚氧乙烯醚(TX-100)的临界胶束浓度的实验效果,明确了2种方法的优劣。 采用挂环法测试了不同浓度SDS和TX-100水溶液的表面张力,得到了它们的临界胶束浓度以及饱和吸附量、分子截面积;采用电导法研究上述2种表面活性剂溶液的电导率曲线,仅得到SDS的临界胶束浓度。与电导法相比,表面张力法得到的表面活性剂性质信息更多,应用更广泛。该实验使学生加深理解不同电性表面活性剂临界胶束浓度的性质及测定方法,明确不同方法的优缺点,扩大知识面,同时也提高学生处理数据的能力,为学生今后进一步学习应用表面活性剂打下良好基础。     

新试剂3,5-二溴-4-偶氮间苯二酚苯基荧光酮与锗配合物的分光光度法研究

本文研究了在表面活性剂Ｔｗｅｅｎ６０存在下，新试剂３，５－二溴－４－偶氮间苯二酚苯基荧光酮与锗（Ⅳ）的显色反应和光度性质。在０．５～１．５ｍｏｌ／ＬＨＣｌ介质中，锗与试剂形成１２的红色三元胶束配合物，最大吸收波长为５３２ｎｍ，表观摩尔吸光系数ε为１．６８×１０５Ｌｍｏｌ－１ｃｍ－１，锗浓度在０～５μｇ／２５ｍｌ范围内符合比尔定律。拟定方法用于煤样中微量锗的分析，结果满意。     

New fluorescence method for the determination of the critical micelle concentration by photosensitive monoazacryptand derivatives

A novel fluorescence method for the determination of the critical micelle concentration (cmc) is reported. The cmc values of nonionic and anionic surfactants were evaluated utilizing a photosensitive monoazacryptand-Ba2+ complex, whose fluorescence intensity is sensitively changed by environmental conditions based on the photoinduced electron transfer (PET) mechanism as a fluorescent probe (PET method). Based on a comparison of the cmc values obtained by the PET method versus those obtained by conventional fluorescence-based methods as well as the values reported in the literature, one can conclude that the PET method is useful for the cmc determination. In particular, the PET method was more effective for the cmc determination of nonionic surfactants with very low cmc values (< 10(-5) M) than any other fluorescence-based method. In the cases of anionic surfactants, the PET method revealed the formation of the premicellar aggregates comprised of surfactant molecules and fluorescent probes below the cmc. Moreover, the hydrophobicity around the monoazacryptand-Ba2+ complex incorporated into various nonionic surfactant micelles was evaluated by this PET method.     

Fluorescence spectroscopy of fulvic acids’ interaction with surfactants

Fluorescence spectra of two fulvic acid (FA) samples, FA0 from underground water and FA1 from forest soil, were recorded in various surfactant solutions. Alkyltrimethylammonium ions with different alkyl chain lengths induced a decrease in the fluorescence intensity for both FAs at concentrations below the critical micelle concentration (cmc) and an enhancement above the cmc. The intensity minimum thus obtained at the cmc was deeper for surfactants with longer alkyl chains. This effect was attributable to the formation of insoluble FA–surfactant complexes below the cmc and to the solubilization of the complex into micelles above the cmc. Dodecylpyridinium chloride caused a monotonic decrease in the FA fluorescence even far above the cmc. This was attributable to the quenching of FA fluorescence by the positioning of the pyridinium head group near the FA fluorophore. Anionic and nonionic surfactants showed little to no effect on the FA fluorescence.     

Surfactant Effects on the Permeability of Photosynthetic Membrane from Rhodobacter sphaeroides 2.4.1 Probed by Electrochromic Shift of Endogenous Carotenoids

Four surfactants, sodium cholate(SC), n-dodecyl-β-D-maltopyranoside(DDM), lauryldimethylamine oxide(LDAO) and Triton X-100(TX), which are generally used in photosynthetic pigment-protein complexes preparation, were studied on their interaction with photosynthetic membrane from Rhodobacter sphaeroides 2.4.1 by electrochromic absorption band-shift of endogenous carotenoids and by vesicle size measurements as well. The surfactant critical micelle concentration(cmc) was found to be negatively correlated with the capability of enhancing the permeability of photosynthetic membranes to proton, and more elaborated model of surfactants interacting with membranes was obtained. The electrochromic absorption band-shift measurement might develop into a useful tool to evaluate the effects of surfactants on various membranes.     

Sorption of a fluorescent whitening agent (Tinopal CBS) onto modified cellulose fibers in the presence of surfactants and salt

The combined effect of salt (10 mmol L(-1)) and surfactants on the sorption of the fluorescent brightener 4,4'-distyrylbiphenyl sodium sulfonate (Tinopal CBS) onto modified cellulose fibers was studied. Sorption efficiencies with both cationic and anionic surfactants were evaluated. Emission spectroscopy was used for quantitative analysis since Tinopal has an intense fluorescence. The sorption efficiency of the brightener is greater for solutions containing a cationic surfactant (DTAC) below the critical micelle concentration (cmc), while for an anionic surfactant (SDS) above its cmc the efficiency is greater. The profile of the sorption isotherms were interpreted in terms of the evolution of surfactant aggregation at the fiber/solution interface. Salt influences the efficiency of the Tinopal sorption on the modified cellulose fibers either because it decreases the cmc of the surfactants or because the ions screen the surface charges of the fiber which decreases the electrostatic interaction among the charged headgroup of the surfactant and the charged fiber surface.     

A simplified method for predicting the dynamic surface tension of concentrated surfactant solutions

A simplified method for predicting the dynamic surface tension of concentrated surfactant solutions is proposed. It is implemented using the framework of the Henry's Law analytical solution to the Ward and Tordai equation for diffusion-controlled adsorption, with the necessary parameters being deduced from the measured equilibrium surface tension equation and a value for the surfactant monomer diffusivity. The method is tested by calculating the dynamic surface tension relaxations of aqueous C10E6 and C10E8 solutions over concentration ranges from well below to well above their critical micelle concentrations (cmc). Results are compared with measured relaxations over 0.001-50 s, and semiquantitative agreement is found, with the best results obtained for concentrations near the cmc. The predictive method may prove useful in such applications as the screening of candidate surfactants for inks used in inkjet printing.     

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.     

Alpha-Lactalbumin is unfolded by all classes of surfactants but by different mechanisms

We show that all four classes of surfactants (anionic, cationic, non-ionic, and zwitterionic) denature alpha-lactalbumin (alphaLA), making alphaLA an excellent model system to compare their denaturation mechanisms. This involves at least two steps in all surfactants but is more complex in charged surfactants due to their strong binding properties. At very low concentrations, charged surfactants bind specifically as monomers, but the first denaturation process only sets in when 4-10 surfactant molecules are bound to form clusters on the protein surface and is followed by a second loss of structure as 20-25 surfactant molecules are bound. Sub-micellar interactions can be modeled as simple independent binding at multiple sites which does not achieve saturation before micelle formation sets in. In contrast, no specific sub-micellar surfactant binding is detected by calorimetry in the presence of zwitterionic and non-ionic surfactants, and denaturation only occurs around the cmc. Unfolding rates are very rapid in charged surfactants and reach a similar plateau level around the cmc, indicating that monomers and micelles operate on a mutually exclusive basis. In contrast, unfolding occurs slowly in zwitterionic and non-ionic surfactants and the rate increases with the cmc, suggesting that monomers cooperate with micelles in denaturation.     

Study of the formation of dye-induced premicellar aggregates and its application to the determination of quaternary ammonium surfactants

Formation of dye-induced mixed premicellar aggregates from binary surfactant solutions is proposed for the determination of alkyltrimethylammonium surfactants at the muM level. The Coomassie Brilliant Blue G (CBBG) dye, negatively charged, induces the formation of cationic surfactant aggregates at concentrations far below the cmc. The role of CBBG in the formation of premicelles was studied by using pyrene as a fluorimetric probe. Formation of CBBG-cationic surfactant aggregates of well-defined stoichiometries that depend on the total surfactant concentration added is demonstrated. Also, the influence of analytical parameters affecting the concentration at which a given aggregate is formed was studied. Linear calibrations for alkyltrimethylammonium surfactants were obtained by using different cationic surfactants as titrants; therefore, the previously derived measurement parameter for mixed micelles is applicable to premicellar aggregates as well.     

Surface tension and aggregation properties of novel cationic gemini surfactants with diethylammonium headgroups and a diamido spacer

A series of novel cationic gemini surfactants with diethylammonium headgroups and a diamido spacer were synthesized, and their surface and bulk properties were investigated by surface tension, electrical conductivity, fluorescence, viscosity, dynamic light scattering (DLS), and transmission electron microscopy (TEM) measurements. An interesting phenomenon, that is, the obvious decline in surface tension upon increasing concentration above the critical micelle concentration (cmc), was found in these gemini surfactant solutions, and two explanations were proposed. This surface tension behavior could be explained by the rapid increase in the counterion activity in the bulk phase or the continued filling of the interface with increasing surfactant concentration above the cmc. More interestingly, not only vesicles but also the surfactant-concentration-induced vesicle to larger aggregate (spongelike aggregate) transition and the salt-induced vesicle and spongelike aggregate to micelle transition were found in the aqueous solutions of these gemini surfactants. The spongelike aggregate that is first reported in the cationic gemini surfactant-water binary system is probably caused by the adhesion and fusion of vesicles at high surfactant concentration.     

乙醇/水混合溶剂中Gemini表面活性剂的表面性质

通过对Gemini表面活性剂12-s-12 (Et)(s=4, 6, 8, 10, 12)体系在乙醇/水混合溶剂中的表面张力曲线的测定, 对该体系的表面性质进行了研究. 发现随乙醇/水比例变化, Gemini各种表面化学性质, 如临界胶束浓度(cmc)、表面张力(γcmc)、饱和吸附量(Γmax)和最小分子占有面积(Amin)等的变化规律. 拓展了Gemini表面活性剂在混合溶剂中表面吸附的研究.