复合表面活性剂的表面特性：临界胶束浓度的测定

用电导、表面张力和折光指数法估算了十二烷基硫酸钠（ＳＬＳ）、十二烷基苯磺酸钠（ＳＤＢＳ）和辛基酚聚氧乙烯基醚（ＯＰ）复合乳化剂的临界胶束浓度（ＣＭＣ）。发现，ＳＬＳ／ＯＰ和ＳＤＢＳ／ＯＰ的ＣＭＳ值约为１０＾－３ｇ／ｍｌ数量级，数据与乳化剂纯度有关，但与复合乳化剂中两者的比例无关。同时对三种测定方法作了评价。     

电导法测定表面活性剂溶液的临界胶束浓度

本文用电导法测定了十二烷基磺酸钠在４０℃和６０℃时的临界胶束浓度（ＣＭＣ），根据“相分离模型”计算了４０℃时十二烷基硝酸钠溶液的胶束形成标准焓变（△Ｈｍ），标准吉布斯自由能变化（△Ｇｍ）和标准熵变（△Ｓｍ）。     

吸附伏安法测定阳离子表面活性剂的临界胶束浓度

以中性红为探针,用吸伏安法测定了十六烷基三甲基溴化铵的临界胶速浓度,基本原理为：存在于表面活性剂溶液中的微量中性红在悬汞电极上的吸附伏安峰电流对表面活性剂浓度的曲线在临界胶束浓度处有一拐点,此点即为阳离子表面活性剂的临界胶束浓度。     

低聚型表面活性剂临界胶束浓度的分光光度法测定

本文在前人的基础上提出了一种采用紫外分光光度法测定聚型表面活性剂的临界胶束浓度的新方法，探讨了不同条件对测定结果的影响，并确立了优化条件。通过对增溶机理的讨论，进一步说明了低聚型表面活性水溶液的特征。     

聚酯型高分子表面活性剂临界胶束浓度的测定：紫外分光光度法

本文通过实验选出了适用于测定聚酯型表面活性剂临界胶束浓度的添加物二甲基偶氮苯,确定了最佳浓度区间,建立了简单,快速的测定方法。     

碘光谱法测定非离子表面活性剂的临界胶束浓度

考察了碘光谱法测定非离子表面活性剂在水溶液中的临界胶束浓度（ｃｍｃ）的影响因素。欲得正确结果，须将碘－胶束溶液（不同浓度）放置，待碘的分配达到平衡（例如２４ｈ）后再进行测定，这样测得ＴｒｉｔｏｎＸ－１００、ＴｒｉｔｏｎＸ－３０５和单分散的纯化合物Ｃ１２Ｈ２５Ｏ（Ｃ２Ｈ４Ｏ）６Ｈ的ｃｍｃ分别为２．４×１０－４、３．５×１０－４和８．４×１０－５ｍｏｌ·ｄｍ－３，与文献中用表面张力法测得的结果一致。若按Ｒｏｓｓ和Ｏｌｉｖｅｒ将预先配好的溶液稀释后１小时内测定的方法，则所得结果偏低。只要测定时碘－胶束溶液已达平衡，则碘浓度在４～１２ｍｇ／１００ｍｌ范围内对ｃｍｃ的测定结果无明显的影响。文献中提到的碘浓度对ｃｍｃ测定值的影响可能是由于碘的分配未达平衡所致。     

溶液中表面活性剂临界胶束浓度降低措施的研究进展

表面活性剂增效技术是近期发展起来并被认为是可对污染地下水进行有效修复的技术之一,但为避免引起新的污染,需控制其投放剂量。综述了通过表面活性剂的优化匹配及水化学组分调节等方式降低表面活性剂的临界胶束浓度,进而实现减少表面活性剂投放量的研究进展,指出其存在的问题,展望其发展前景。     

人工神经网络预测阴离子表面活性剂的临界胶束浓度

根据定量结构-性能关系原理,利用人工神经网络模型,采用Wn、S和Sn三种拓扑指数描述阴离子表面活性剂的分子结构并作为网络输入,预测阴离子表面活性剂的临界胶束浓度。确定了网络参数,利用43组数据对网络进行训练和预测,并与文献值进行了比较。结果表明,预测精度较高,说明人工神经网络方法具有很好的预测能力。     

电导法测定阳离子型表面活性剂临界胶束浓度实验研究

采用电导法测定一定温度下不同浓度的十四烷基三甲基氯化铵(TTAC),十六烷基三甲基氯化铵(CTAC),十八烷基三甲基氯化铵(STAC)溶液的电导率值,计算摩尔电导率,研究碳链上碳原子数对表面活性剂临界胶束浓度(CMC)的影响。结果表明:CMC(TTAC)=0.00580 mol/L,CMC(CTAC)=0.0041mol/L,CMC(STAC)=0.0039 mol/L,可知随着碳链上碳原子个数的增多,相应的临界胶束浓度(CMC)呈减小趋势。     

基于正规溶液理论计算三元混合表面活性剂的临界胶束浓度

随着溶液pH的降低,TX-100/N,N-二甲基十二烷基氧化胺二元表面活性剂混合体系变为三元表面活性剂混合体系;利用滴体积法测定了不同pH时该混合体系的临界胶束浓度,并利用正规溶液理论计算了该三元表面活性剂混合体系的临界胶柬浓度,计算结果在一定范围内与实验较好地相符.     

Fluorescence technique for the determination of low critical micelle concentrations

A technique for determining low critical micelle concentrations (CMC) by means of a hydrophobic fluorescence probe has been developed. The amount of the fluorescent probe at the CMC is so small that the effect of the probe on micelle formation is negligible. The fluorescence intensity was measured at fixed dye/surfactant ratios, and it decreased with concentration. A quantity proportional to fluorescent quantum yield was calculated and found to be high for concentrations of surfactant above the CMC and almost zero below the CMC, giving a distinct break in the quantum yield vs. the concentration curve.     

Alanine-based surfactants: Synthesis and some surface properties

A homologous series of anionic surfactants, namely, sodium-N-(alkyloxycarbonyl) alanine (where alkyl=octyl-, dodecyl-, hexadecyl-, and octadecyl-) were synthesized having the formula: R-OCO-CH₂NH-CH₂-CH₂-COONa. Surface properties of their solutions, including surface tension, critical micelle concentration, effectiveness, maximum surface excess, and minimum surface area, were investigated for different concentrations at 25°C. The effects of these surfactants on the solubilization of a polar and a nonpolar solute were studied. Standard free energies of micellization and adsorption were calculated for the prepared surfactants in aqueous solution.     

胶团强化超滤中SDS临界胶团浓度变化规律研究

用电导法对十二烷基硫酸钠(SDS)的临界胶团浓度(CMC)进行了研究,考虑了温度、pH值、金属离子(Cd2+、Zn2+、Pb2+)浓度变化以及SDS和3种非离子表面活性剂(Brij35、TritonX-100、APG)的复配对溶液CMC值的影响。结果表明,随温度升高,pH值上升,金属离子浓度增加以及Brij35/SDS、TritonX-100/SDS、APG/SDS混合体系配比的增加,溶液CMC值减小。特别当复配比在0.13～1时,CMC值的下降趋势非常明显。这一结果为采用胶团强化超滤技术处理电解锌废水时SDS最佳添加量的确定提供了有效的依据。     

Critical micelle concentrations of ternary surfactant mixtures: Theoretical prediction with user-friendly computer programs and experimental design analysis

We studied the behavior of an aqueous ternary surfactant mixture composed of a nonionic surfactant and two anionic surfactants which differ in both surfactant hydrophobic tail length and surfactant hydrophilic head structure. We used an experimental design program to calculate the critical micelle concentrations (CMCs) of this ternary surfactant mixture over the entire range of solution compositions. As inputs, the experimental design methodology requires the values of the ternary surfactant mixture CMCs for a limited subset of solution compositions which is determined by the experimental design program. We showed that this subset of ternary surfactant mixture CMC values can either be measured experimentally or predicted theoretically. The theoretical CMCs were predicted by a series of userfriendly computer programs which are based on molecular-ther-modynamic theories describing single and mixed micelle formation. The experimental design program generated two surfaces describing the ternary surfactant mixture CMCs over the entire solution composition range—one based on the experimentally measured subset of CMC values, and the other based on the theoretically predicted CMC values for the same subset of solution compositions. We found that these two CMC surfaces agree very well, thus demonstrating the utility of the computerassisted molecular-thermodynamic modeling as a predictive tool in surfactant mixture characterization and design.     

Polymeric surfactants for enhanced oil recovery. Part I—critical micelle concentration of some ethoxylated alkylphenol—formaldehyde nonionics

Four low molecular weight nonionic polymeric surfactants were prepared by condensing octyl-, dodecyl-, tetradecyl- and hexadecylphenol with para-formaldehyde, and then reacting the resulting resins with ethylene oxide to obtain products with the desired degree of ethoxylation. The molecular weights of the prepared alkylphenol-formaldehyde resins (prior to ethoxylation) were determined by vapour pressure osmometry. The surface tensions of aqueous solutions of these nonionic polymeric surfactants were determined by using the spinning drop method. Plotting the surface tensions obtained versus the logarithm of concentrations resulted in two lines: the pre-CMC (CMC = critical micelle concentration) line (the linear portion below the CMC value) and the post-CMC line (the linear portion above the CMC value). Least squares regression analysis was performed to get the best equation for each of the two lines. Solving these two equations simultaneously resulted in the value of the CMC and the corresponding surface tension (γ_CMC) for each surfactant of the four polymeric nonionic groups. The CMC values obtained for these polymeric surfactants are of the same order of magnitude obtained for monomeric and other polymeric nonionic surfactants.     

吸附伏安法测定阳离子表面活性剂的临界胶束浓度

以中性红为探针,用吸附伏安法测定了溴化十六烷基三甲铵的临界胶束浓度。     

分光光度法研究十二烷基硫酸钠的临界胶束浓度

在碘的水溶液和I<'-><,3>溶液2种体系中测定了十二烷基硫酸钠(SDS)的临界胶束浓度(CMC),并讨论了在I<'-><,3>体系中,不同硫酸钠和氯化钾2种盐对测定结果的影响,在碘的水溶液中研究了不同碘浓度对SDS的CMC的影响.采用分光光度法求得SDS在两种体系中的CMC值,硫酸钠与氯化钾对CMC的值有影响,且无...