Poly(N-ethyl-4-vinylpyridinium bromide)–sodium dodecyl sulfate complexes. Formation and supramolecular organization in salt containing aqueous solutions

Formation and supramolecular organization of poly(N-ethyl-4-vinylpyridinium bromide) (PEVP)–sodium dodecyl sulfate (SDS) complexes in aqueous-salt solutions have been studied. PEVP samples of three polymerization degrees (P_w = 570, 1200 and 2350) were used. For PEVP of lower polymerization degree (P_w = 570) only insoluble complexes were observed in the whole range of the reaction mixture composition studied: Z = [SDS]/[PEVP] ≤ 1. For PEVP of higher polymerization degrees (P_w = 1200 and 2350), water-soluble complexes are formed up to a critical value of the reaction mixture composition, Z, that is similar for both PEVP fractions. It was found that water-soluble complex species are either molecularly dispersed (i.e. each complex particle comprises only one macromolecule) or aggregated (includes about 40 polymer chains and 20,000 surfactant ions) depending on the complex composition. Complex composition, in its turn, was shown to be determined by PEVP polymerization degree and the reaction mixture composition.     

Electro-oxidation of sodium lauryl sulfate aqueous solutions

The electro-oxidation of dilute aqueous solutions of sodium lauryl sulfate (LS) was studied in the presence of metal ions and sulfuric acid, in order to achieve the complete destruction of the detergent. An undivided cell and rhodiated titanium electrodes were used. The LS concentration was studied as a function of time, added metal ion, pH, temperature, initial current density and detergent concentration. The results obtained showed that 99% LS destruction can be easily achieved and that complete oxidation occurs. LS depletion rate was found to increase with temperature, current density (up to 2 A dm^–2) and detergent concentration but to decrease with pH. The best results were obtained with iron ions dissolved in the electrolyte, but the process rate was nearly independent of Fe concentration above 0.5 mM.     

十二烷基硫酸钠对聚乙烯吡咯烷酮水溶液黏度特性的影响

利用乌氏黏度计在(30±0.05)℃条件下研究了不同聚乙烯吡咯烷酮(PVP)质量浓度与不同十二烷基硫酸钠(SDS)浓度组合的复合溶液的黏度,观察到PVP-SDS溶液黏度曲线上存在双临界浓度c1和c2,表明在c1和c2之间SDS以束缚胶束形式簇集在PVP高分子链上;研究了不同"比簇集量"的PVP-SDS团簇溶液的比浓黏度特性,发现比浓黏度随PVP质量浓度降低反而显著增大,偏离了单纯PVP溶液而与典型的聚电解质聚丙烯酸钠(Na PAA)溶液相似;计算了PVP-SDS团簇中高分子链的均方末端距r2及其与单纯PVP类比的链相对扩张量k值,发现随着比簇集量[Г]增加k值增大。根据实验结果,将上述现象解释为由于带电的SDS束缚胶束簇集在PVP高分子链上,产生了"聚电解质效应",从而导致高分子链扩张。     

Interactions of aminoalkylcarbamoyl cellulosics and sodium dodecyl sulfate. I. Surface tension

We have compared the interactions between Polyquaternium 10 and sodium dodecyl sulfate (SDS) with similar complexes of mono and diquaternary aminoalkylcarbamoyl cellulose derivatives by measuring the surface tension of their aqueous solutions. The results indicate that reduction of surface tension of aqueous solutions occurs via the formation of highly surface active polymer–surfactant complexes. At approximately a 1 : 1 stoichiometric ratio of SDS to quaternary groups, a complex of low solubility forms which is more efficient at reducing surface tension than the surfactant alone. The ability of the polymer–surfactant complex to reduce surface tension appears to be independent of polymer architecture and dependent only upon adsorption of the surfactant species at the cationic polymer sites. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1091–1097, 1998     

十二烷基苯磺酸钠与非离子氟碳表面活性剂复合驱油剂的研究

研究了十二烷基苯磺酸钠(SDBS)/氟碳Intechem-01表面活性剂(FC-01)复合驱油剂的性能,以驱油率、界面张力、与注入水和模拟地层水的配伍性为考察指标,正交实验结果表明,氟碳Intechem-01表面活性剂的质量分数为0.05%,十二烷基苯磺酸钠的质量分数为0.15%,碳酸钠、碳酸氢钠的质量分数都为0.25%时,复配体系的效果较好,且复配体系与定边油田采油注入水和模拟地层水有良好的配伍性。     

十二烷基硫酸钠与氟碳表面活性剂混合体系的溶液性能

测定新型非离子氟碳表面活性剂(Intechem-01)与十二烷基硫酸钠(SDS)混合体系的表面张力、cmc、泡沫性能,研究了两者之间的相互作用。结果表明:Intechem-01与SDS质量比为3:1时,体系表面张力最低,cmc最小,体系出现最大协同效应;并且Intechem-01显示了良好的稳泡性能,当其与SDS质量比为5:1时,混合体系25%析液时间可达99.2s。     

Precipitation in solutions containing mixtures of synthetic anionic surfactant and soap. I. Effect of sodium octanoate on hardness tolerance of sodium dodecyl sulfate

The effect of sodium octanoate (SO) and pH on the precipitation of sodium dodecyl sulfate (SDS) with calcium (hardness tolerance) in water was investigated. SO can exist as octanoate anion (O⁻) or as the protonated nonionic fatty acid (HO) with the HO/O⁻ ratio increasing with decreasing pH. At intermediate pH levels, SO or SO/SDS systems are composed of mixtures of anionic and nonionic surfactants, resulting in enhancement of micelle formation due to nonideal mixed micelle formation. Above the critical micelle concentration (CMC), the highest hardness tolerance at each pH level occurs at a mole ratio of 80∶20 SDS/SO due to synergism in the SDS/SO mixtures. This synergism also results in an increase in hardness tolerance of SDS with decreasing pH above the CMC.     

Solution properties of mixed surfactant system sodium dodecyl sulfate and alkyl polyoxyethylene ether system

The effect of oxyethylene groups in a nonionic surfactant on the solution properties of anionicnonionic systems is described; these systems are sodium dodecyl sulfate (SDS)—hexadecyl polyoxyethylene ethers (C₁₆POE_n, where n=10, 20, 30 and 40). The degree of ionic dissociation of the mixed micelles decreases with increasing numbers of oxyethylene groups in the nonionic surfactant. As polyoxyethylene chain lengths increase, the electrical conductivities of the mixed surfactant solutions decrease, in spite of the decrease in activation energy for conduction. The radius of the mixed micelle with the electric double layer is larger for a nonionic surfactant having a shorter polyoxyethylene chain length than for one having a long polyoxyethylene chain. This may be attributed to the fact that the mixed micelle is formed more easily by a nonionic surfactant with a shorter polyoxyethylene chain length than by one with a longer chain.     

十二烷基苯磺酸钠水溶液聚集性质的研究

用滴体积法测出十二烷基苯磺酸钠（ＳＤＢＳ）稀水溶液的表面张力；然后求出其临界胶束浓度（ＣＭＣ）。同时通过溶液的电导率、吸收光谱以及荧光光谱测定求出其ＣＭＣ。这样测出的ＣＭＣ值为１．２～１．６×１０－３ｍｏｌ／Ｌ，与文献值相符。也研究了部分水解的聚丙烯酰胺（ＰＨＰＡＭ）对ＳＤＢＳ聚集性质的影响；发现ＳＤＢＳ的ＣＭＣ值随ＰＨＰＡＭ的加人而减少并且ＰＨＰＡＭ水溶液的粘度随ＳＤＢＳ的存在而急剧降低（类似盐效应）。这些方法与性质对强化采油（ＥＯＲ）是重要的。     

Changes in phospholipid bilayers caused by sodium dodecyl sulfate/nonionic surfactant mixtures

The interaction of mixtures of sodium dodecyl sulfate (SDS) and oxyethylenated nonylphenol (30 mol of ethylene oxide) [NP(EO)₃₀] with phosphatidylcholine liposomes was investigated. Permeability alterations were detected as a change in 5(6)-carboxyfluorescein (CF) released from the interior of vesicles, and bilayer solubilization was measured as a decrease in the static light scattered by liposome suspensions. Three parameters were described as the effective surfactant/lipid molar ratios (Re) at which the surfactant system: (i) resulted in 50% CF release (Re _50%CF); (ii) saturated the liposomes (Re _SAT); (iii) led to complete solubilization of these structures (Re _SOL). The corresponding surfactant partition coefficients (K _50%CF, K _SAT, and K _SOL) were determined from these parameters. The free surfactant concentrations S _W were lower than the mixed surfactant critical micellar concentration at subsolubilizing levels, whereas they remained similar to these values during saturation and solubilization of bilayers. Although the Re values increased linearly as the mole fraction of the SDS rose (X _SDS), the K parameters showed maximum values at X _SDS 0.6 for K _50%CF and approximately at X _SDS 0.2 for K _SAT and K _SOL, respectively. Thus, the lower the surfactant contribution in the surfactant/lipid system, the higher the X _SDS at which the maximum bilayer/water partitioning of added mixed surfactant systems occurred. As a consequence, the influence of SDS in this partition appears to be more significant at the sublytic level (monomeric effect), whereas the influence of NP(EO)₃₀ seems to be greater during saturation and solubilization of liposomes via formation of mixed micelles.     

Influence of sodium dodecyl sulfate on the characteristics of bovine serum albumin solutions and foams

Results from surface tension measurements on mixed solutions of the protein bovine serum alburnin (BSA) and an anionic surfactant (SDS: sodium dodecyl sulfate) suggested that at an air-liquid interface, adsorption was affected by the protein-surfactant interaction and by the relative concentration of each component in solution. Two plateaus corresponding to the critical aggregation concentration (CAC) and the critical micelle concentration (CMC) of SDS, respectively, were observed in the surface tension isotherms of SDS in the presence of BSA. The CAC and CMC depended on the concentration of BSA. Effects of SDS concentration on the conformational changes of BSA were investigated by Fourier transform-Raman spectroscopy. The results showed that the contents of α-helix decreased while the contents of random coil increased. The presence of the anionic surfactant SDS had a negative influence on the way that proteins adsorb at an air-liquid interface, leading to the change of behavior of protein-stabilized film.     

Entry in emulsion polymerization using a mixture of sodium polystyrene sulfonate and sodium dodecyl sulfate as the surfactant

A mixture of sodium polystyrene sulfonate (NaPSS) and anionic surfactant, sodium dodecyl sulfate (SDS), was used as the emulsifier in the emulsion polymerization of styrene at 60 °C. The latexes prepared were stable, bearing the better resistance to the addition of electrolyte, and have the larger values in particle size and the higher polymerization rates than those counterparts prepared using SDS only. The NaPSS was prepared by a series of process: a concentrated cyclohexane solution of an anionically polymerized polystyrene (PS) was sulfonated with sulfuric acid at 80 °C, and then neutralized and purified through dialysis. The data of average polymer number per particle (n_p) were found useful in investigating the surfactant content effect on the entry of radicals into particles, where the latex particle size plays an important role.     

A comparison of surface tension data for aqueous dodecylammonium salt solutions

Literature data for natural solutions is compared and a wide spread of surface tension values is shown. A comparison of three techniques, capillary rise, drop weight and maximum bubble pressure failed to indicate that the technique alone was responsible. Repeating the determinations at pH 9.5 did indicate marked dependence on the technique employed. Wetting problems coupled with a pronounced time dependence of the surface tension were responsible. The bubble pressure method is shown to be the most suitable, being versatile enough to handle the dynamics. A comparison of critical micelle concentration (c.m.c.) data as a function of pH with the calculated solubility limit of dodecylamine as a function of pH revealed an interesting incompatibility; at pH greater than 9, the indicated c.m.c. was greater than the solubility limit.     

Two-phase aqueous systems of cetyltrimethylammonium bromide/sodium dodecyl sulfate with and without polyethylene glycol

Aqueous two-phase systems of cetyltrimethylammonium bromide and sodium dodecyl sulfate mixtures without and with polyethylene glycol (PEG) added have been studied at 313.15 K. The results have shown that PEG has a strong effect on the phase diagram of ATPS and microstructures of surfactants aggregates. The addition of PEG leads to the formation of bigger surfactant aggregates, which can be attributed to both the screening effect and the connection effect of PEG. All ATPS, especially those with PEG added, may have potential applications in separation and purification of biomaterials.     

纳米SiO_2/表面活性剂对油水界面张力的影响

以液体石蜡为油相,考察了疏水性纳米SiO_2对阴离子表面活性剂SDS、阳离子表面活性剂CTMAB与非离子表面活性剂OP-10的协同效应,以及Na Cl浓度对复配体系油水界面张力的影响。试验结果表明:纳米SiO_2与SDS和CTMAB之间具有良好的协同作用,且油水界面张力在400 s内变化明显,超过600 s后几乎不再变化;质量分数0.004%的纳米SiO_2与SDS和CTMAB复配后随着表面活性剂浓度升高(0.001 mol/L升至0.1 mol/L),协同效应越来越不明显,但表面活性剂浓度稀释至0.1 mmol/L后纳米颗粒分散稳定性差;随着NaCl浓度升高,与单一表面活性剂相比,SDS/SiO_2协同作用先增强后减弱,CTMAB/SiO_2协同作用持续减弱且200 s内界面张力变化幅度较大;纳米SiO_2与OP-10之间未观察到明显的协同作用,但OP-10分散稳定性强,即使在高矿化度也具有良好的分散能力。     

The effect of micellar lifetime on the rate of solubilization and detergency in sodium dodecyl sulfate solutions

The slow relaxation time (τ₂) of sodium dodecyl sulfate (SDS) micelles, measured by the pressure-jump technique, was maximum at 200 mM concentration at 25°C, indicating that the most stable micelles are formed at this concentration. This is presumably related to the optimum molecular packing in the micelle. The rate of solubilization of benzene and Orange OT dye into SDS solutions was also maximum at 200 mM concentration. The results are explained as follows: The distance between micelles (i.e., intermicellar distance) decreases as the surfactant concentration (or the number of micelles) increases, resulting in a stronger electric repulsion between micelles. Therefore, the micelles become more rigid, due to the compressive force of intermicellar repulsion, as the concentration increases up to 200 mM SDS. With further increase in the SDS concentration, the micellar shape changes from spherical to cylindrical to accommodate more surfactant molecules in the solution and to minimize the free energy of the system. The interior of the tightly packed micelles is more hydrophobic than that of loosely packed micelles and, therefore, the tightly packed micelles induce rapid solubilization of nonpolar molecules (e.g., benzene, Orange OT) into these micelles.     

Influence of detergent builders on surface properties of sodium dodecyl sulfate solutions under dynamic and static conditions

The effects of various detergent builders on surface properties of sodium dodecyl sulfate (SDS) solutions have been investigated by measuring the equilibrium surface tension and hysteresis curves of surface pressure vs surface area under dynamic conditions. While the adsorbed layer of SDS under static conditions is in the liquid-expanded state, a two-dimensional phase transition of the adsorbed layer from liquid-expanded to condensed-film can be observed on compression at higher rates beyond the saturated adsorption. For the SDS solution containing excess NaCl (1×10⁻¹ M), the adsorbed layer of SDS is already in the condensed state under static condition due to a depression in the dissociation of SDS. It has been found that some polyelectrolytes, as well as conventional ionic builders, contribute to increasing the surface excess concentration of SDS together with promoting micelle formation and also to stabilizing the adsorbed layer of SDS. On the other hand, poly(vinyl alcohol) (PVA) as a nonionic polymer is adsorbed at the air-water interface in preference to SDS. In this case, the hysteresis of the dynamic surface behavior of the mixed solution can be attributed to the structural change of the adsorbed layer of PVA rather than SDS, which is different from the other ionic builders.     

芳基烷基磺酸盐链长对烷烃的油-水动态界面张力的影响

采用旋转滴法测定系列自制芳基烷基磺酸盐（C_nNPAS, n=8,10,12,14,16）水溶液对烷烃的油-水动态界面张力,考察了表面活性剂烷基链长、表面活性剂浓度、弱碱浓度、烷烃碳数等因素对油-水动态界面张力的影响。结果表明,增大C_nNPAS的烷基链长和碱含量均会使界面张力达到稳定值的时间增长;增加C_nNPAS浓度和烷烃碳数均会使界面张力动态变化加快,达到平衡所需时间减少。C_nNPAS表面活性剂可在低浓度范围较明显地降低界面张力,而随着浓度的增加界面张力回升明显。     

十二烷基硫酸钠对膜蒸馏过程影响

膜蒸馏具有较低的操作压力、操作温度以及运行成本等优点，因此在水处理方面有广泛的应用前景。但是膜蒸馏过程中的膜润湿和膜污染现象仍然是阻碍其工业化应用的主要问题。表面活性剂作为一种能显著降低溶液表面张力、改变进料液性质的物质，对膜蒸馏造成的影响值得被研究。基于此，研究了在直接接触式膜蒸馏（DCMD）过程中表面活性剂对不同商业微孔疏水膜造成的影响，选用了一种常见的阴离子表面活性剂十二烷基硫酸钠(SDS)进行实验。结果表明，进料液中SDS浓度的上升会引起更为严重的膜润湿现象，并且所使用的三种商业膜中，双疏膜抗润湿性最强，而PVDF膜最弱。而当Ca²⁺大量存在于进料液中时，Ca²⁺与SDS的聚集降低了膜润湿的程度但其在膜表面的沉积造成了严重的膜污染。界面相互作用自由能的计算结果表明Ca²⁺/SDS与PVDF膜之间的吸引力最大、PTFE膜其次、双疏膜最小，这一结果与膜蒸馏过程中通量变化情况相符。     

石墨烯修饰微生物燃料电池降解十二烷基磺酸钠

以十二烷基磺酸钠为阳极电子供体,同时以石墨烯为催化剂对电极进行修饰。将修饰前后微生物燃料电池的产电性能和十二烷基磺酸钠的降解情况进行对比,经过修饰的电极装置产电效率明显增大,最大电压增加了1倍,并使十二烷基磺酸钠的降解率从49.85%提高到65.11%。这说明用石墨烯修饰后的微生物燃料电池在稳定产电的同时降解十二烷基磺酸钠是可行的,为废水中阴离子表面活性剂的去除提供了新的方法与研究方向。