Interaction of Nonionic Surfactant Triton-X-100 with Ionic Surfactants

The interaction in two mixtures of a nonionic surfactant Triton-X-100 (TX-100) and different ionic surfactants was investigated. The two mixtures were TX-100/sodium dodecyl sulfate (SDS) and TX-100/cetyltrimethylammonium bromide (CTAB) at molar fraction of TX-100, α_TX-100 = 0.6. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γ_CMC), maximum surface excess concentration (Γ_max), and minimum area per molecule at the air/solution interface (A _min) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were also determined. Mixtures of both TX-100/SDS and TX-100/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.     

Spectrophotometric Determination of Some Antibacterial Drugs Using p-Nitrophenol

Abstract

A simple, quick and sensitive spectrophotometric method for pipemidic acid, norfloxacin and ciprofloxacin lactate is described, based on a reaction with p-nitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complexes with analytically useful maximum absorption at 404 nm, 407nm and 403nm. Optimum conditions for determination, linear calibration range and apparent molar absorptivities have been reported. The methods are highly accurate and have been successfully applied to the determination of pipemidic acid, norfloxacin and ciprofloxacin lactate in tablets. The results are in good agreement with the official methods.     

The Micellar Dissociation Concentration of Polyoxyethylene Mono N-Decylether Nonionic Surfactants in Water

This paper will demonstrate a method for determining the micellar dissociation concentration (MDC) of polyoxyethylene mono n-decylether nonionic surfactants in water. Turbidity and surface tension measurements were applied to commercial samples without further purification. Complicated curves containing turbidity maxima and surface tension minima were obtained for some impure samples. It is difficult to determine the critical micellar concentration (CMC) for impure surfactants. Explanations are given for all curves obtained for pure and impure samples and the method of identifying the MDC values is illustrated. It is more practical for surfactant users to determine the MDC values in their own laboratory than to search for the CMC values in the literature when the surfactants arc impure.     

Interaction of Polyacrylamide with Conventional Anionic and Gemini Anionic Surfactants

The interaction of polyacrylamide (PAM) with conventional anionic (sodium lauryl sulphate, NaLS) and gemini anionic (sodium salt of bis(1-dodecenyl succinimic acid), represented as NaBDS) surfactants has been studied in alkaline medium by electrical conductance and surface-tension measurements at 35⁰C in order to compare the behavior of two surfactants toward the polymer. The surface parameters and thermodynamic parameters have been evaluated and compared. The results indicate more readily interaction of anionic gemini surfactant with the polymer (PAM).     

Thermodynamic and Dynamic Properties of Micellar Aggregates of Nonionic Surfactants with Short Hydrophobic Tails

The densities and viscosities of binary aqueous mixtures of poly(ethylenoxide)hexanols [C₆H₁₃(OCH₂CH₂)_mOH, C₆E_m] (m= 3, 4, and 5) have been studied in the micellar composition range. For the same surfactants the self-diffusion coefficients in mixtures with heavy water have been determined by the spin-echo pulsed field gradient method. The volumetric data are interpreted by means of the phase separation model, and values of the CMC, volume change, and standard free energy change of micellization are obtained. From the viscosity data the hydration numbers of the surfactant hydrophilic head in the micellar state are computed; they are in agreement with those obtained from HDO self-diffusion data. The surfactant self-diffusion data are used to calculate the apparent micelle radius and the aggregation number. The micellization parameters obtained for the different surfactants are compared and discussed.     

Physicochemical Investigation of the Micellar Behavior of a Diblock (PEO)62-b-(PBO)33 Copolymer in Water and its Interaction with Ionic Surfactants

The physicochemical investigations on the associative, micellar, and thermodynamic properties of a diblock (PEO)₆₂-b-(PBO)₃₃ copolymer in aqueous medium and its interaction with ionic surfactants were carried out by using surface tensiometry, laser light scattering, and steady-state fluorescence spectroscopy. Surface tension and fluorescence measurements were used to find out the critical micelle concentration (CMC) and related thermodynamic parameters of micellization copolymer at various temperatures. The data from dynamic light scattering (DLS) were helpful to obtain the values of hydrodynamic radii (R_h), volume (υ_h), and hydrodynamic expansion parameter (δ_h) of the copolymer micelle. Likewise, the measurements from static light scattering (SLS) were employed to determine weight-average molar (M_w), association number (N_w), thermodynamic radius (R_t), thermodynamic volume (υ_t), anhydrous volume (υ_a), and thermodynamic expansion parameter (δ_t) of the copolymer micelles in the temperature range of 20–50°C. Similarly, the interactions between (PEO)₆₂-b-(PBO)₃₃ and two ionic surfactants, sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB), have also been investigated by fluorescence spectroscopy and DLS at 30°C. Similarly, the interactions between (PEO)₆₂-b-(PBO)₃₃ and two ionic surfactants, sodium dodecyl sulfate and hexadecyl trimethylammonium bromide, have also been investigated by fluorescence spectroscopy and DLS in detail.     

Interaction of Anionic Gemini Surfactants with Other Surfactants

The interaction of anionic gemini surfactants with other surfactants (such as anionic, cationic, nonionic) was systematically overviewed, paying attention to synergism observed in various properties. These mixed systems were found to show remarkable synergism in micelle formation. The critical micelle formation values being lower than the individual gemini surfactants indicate that the mixed micellization is due to attractive interaction between the two components. Almost all combinations were discussed in terms of respective surface tension reduction effectiveness and surface tension reduction efficiency and aggregation number for evaluation of synergism.     

Synergistic Behavior of Binary Mixed Micellar Solution

Conductivity measurement has been used to study the properties of aqueous solutions of the nonionic polyoxyethylene sorbitan(20)monooleate (T₈₀) and the cationic 1,1′ lauryl amido propyl ammonium chloride (LAPACl) and their mixtures in the presence of 0.1 M HCl and at 303 K. The values of the critical micelle concentration (CMC) of the individual surfactants and their mixtures were determined from the conductometric measurements. Based on Rubingh's theory (approximation of the theory of regular solutions), the compositions of micelles (X₁), and the parameters of interaction between the molecules of cationic and nonionic surfactants (β) were calculated for mixture of systems LAPACl+α T₈₀ and T₈₀+α LAPACl. The mixture LAPACl+α T₈₀ showed synergistic interactions up to α=0.2 whereas those of T₈₀+α LAPACl registered antagonistic behavior. The study disclosed that for cationic/nonionic surfactants mixtures, the priority is for mixtures of cationic base with small mole fraction of nonionic surfactant and not the reverse.     

Catalytic Spectrophotometric Determination of Ultratrace Amounts of Silver with Solubilizing Effect of Nonionic Surfactant

ＩｎｔｒｏｄｕｃｔｉｏｎＴｒｉａｚｅｎｅｒｅａｇｅｎｔｓａｒｅｉｎｔｅｒｅｓｔｉｎｇｂｅｃａｕｓｅｏｆｔｈｅｉｒｓｔｒｏｎｇｃｏｍｐｌｅｘａｔｉｏｎａｂｉｌｉｔｉｅｓｗｉｔｈｔｒａｎｓｉｔｉｏｎｍｅｔａｌｓ .1 6Ｈｏｗｅｖｅｒ,ｌｉｔｔｌｅｄｅｃｏｌｏｒａｔｉｏｎｏｆｔｈｅｍｃａｔａｌｙｚｅｄｂｙｓｉｌｖｅｒｉｏｎｈａｓｂｅｅｎｓｔｕｄｉｅｄｉｎａｎａｌｙｔｉｃａｌｃｈｅｍｉｓｔｒｙ .Ｍａｎｙａｎａｌ ｙｓｉｓｔｓｈａｖｅｒｅｐｏｒｔｅｄｔｈｅｕｓｅｏｆｃａｔａｌｙｔｉｃｒｅａｃｔｉｏｎｓｆｏｒｔ…     

Salt Effect,Surface, and Aggregation Properties of Binary Surfactant Mixtures of a Nonionic Gemini Surfactant (HBA(EO)80) with Anionic Surfactants

Nonionic gemini surfactants HBA(EO)₈₀ were synthesized and characterized by means of surface tension measurements. CMCs of two mixed system, nonionic gemini mixed with anionic gemini (HBA(EO)₈₀/C11pPHCNa) and nonionic gemini mixed with anionic monomeric (HBA(EO)₈₀/SL) and the effect of salt on the two mixed system were investigated. Freeze-fracture transmission electron microscopy and scanning electron microscopy were used to investigate the mixed aggregates' morphologies. The results show that large spherical aggregates were formed in the mixed solution, which trend to transfer into micelles with the increases of the salt concentration.     

Spectrophotometric determination of cationic and anionic surfactants with anionic dyes in the presence of nonionic surfactants,part I: A general aspect

The behavior of color development of anionic azo dyes, methyl orange and its analogues, was examined in aqueous media by changing the microenvironment of the dyes. The addition of alcohols, organic onium ions, anionic surfactants and nonionic surfactants brought about a decrease of the band at wavelengths near 480 nm and an increase of the band at wavelengths near 420 nm. Such a shift toward the shorter wavelengths in spectra was attributed to the change of the micro-environment around the dyes from a polar field to a less polar field; that is, the shift is caused by the change of the contribution of the following resonance forms, On the basis of the color change phenomena, the spectrophotometric methods for the determination of organic onium ions and anionic surfactants were proposed.     

几种聚氧乙烯型非离子表面活性剂的分光光度法测定及其应用

介绍了几种聚氧乙烯型非离子表面活性剂的KI-I2分光光度法测定,讨论不同实验条件对测定的影响。结果表明,以碘-碘化钾溶液为显色剂的KI-I2分光光度法测定波长为500nm,显色时间为120min,Brij35,Brij30,TritonX-100和Tween-80工作曲线相关系数在0.9971~0.9995之间;检测范围分别为0.2~25mol/L、0.4~25mol/L、1.5~50mol/L和0.5~50mg/L;操作简单,酸稳定性好,大部分盐类、非离子和阴阳表面活性剂、土壤腐植酸、土壤浸提液对测定的干扰小;易水解的Al3 和Fe3 对测定有较大的干扰,但加酸后即可消除。方法直接用于测定聚氧乙烯型非离子表面活性剂在土壤上的吸附等温线获得了满意的效果。     

连接基长度对Gemini表面活性剂胶团间相互作用的影响

用电导率法和动态光散射法测定十二烷基三甲基溴化铵和季铵盐型Gemini表面活性剂胶团的电离度和扩散系数,并结合DLVO理论研究联接基长度和电解质浓度对胶团间相互作用的影响.实验结果表明,联接基团长度会改变胶团电离度和胶团表面电荷密度,从而影响胶团间的相互作用,其影响程度主要取决于联接基的吸电子能力和Gemini表面活性剂分子中两个带电基团的电荷重叠程度;电解质浓度对胶团间相互作用的影响可分为两种情况:在低电解质浓度时,胶团间的相互作用以排斥力为主,不利于胶团的生长;而在高电解质浓度时,胶团间的相互作用以吸引力为主,有利于胶团的生长.     

Spectrophotometric Determination of Polyoxyethylene Nonionic Surfactants in Ground Waters Using Triple-Stage Solid-Phase Extraction Followed by an Improved Ferric Thiocyanate Complexation Method

A practical spectrophotometric determination method for polyoxyethylene nonionic surfactants in ground waters was established, which is based on a ferric thiocyanate complexation colorimetric method preceded by a triple-stage solid-phase extraction technique using SCX, SAX, and C18 cartridges interconnected. Cationic and anionic surfactants interfere with the determination and were therefore effectively trapped and isolated by the SCX and SAX solid phases, respectively. Nonionic surfactants (NSs) were finally introduced and concentrated in the C18 cartridge. The analyte was quantitatively eluted from the C18 sorbent, and the residue was subjected to the colorimetric determination. The calibration line was linear (r² = 0.9997) up to 200µgL^–1 of heptaoxyethylenedodecylether when analyzing sample sizes of 100mL. Overall recoveries were 95–97% with an RSD of less than 3%. The method was applied to the analysis of river water, and 6.4µgL^–1 of NSs as heptaoxyethylenedodecylether was found by means of the standard addition method. The proposed method is very practical and features minimum consumption of chemicals.     

Mechanism of the Micellar Solubilization of Curcumin by Mixed Surfactants of SDS and Brij35 via NMR Spectroscopy

The micellar solubilization mechanism of curcumin by mixed surfactants of SDS and Brij35 was investigated at the molecular scale by NMR spectroscopy. Through the investigation of the micelle formation process, types and structures of mixed micelles and solubilization sites, the intrinsic factors influencing the solubilization capacity were revealed. For systems with α_SDS = 0.5 and 0.2, the obtained molar solubilization ratios (MSRs) are consistent with the MSR_ideal values. However, for α_SDS = 0.8, the solubilization capacity of curcumin is weakened compared to the MSR_ideal. Furthermore, only one single mixed SDS/Brij35 micelles are formed for α_SDS = 0.5 and 0.2. However, for α_SDS = 0.8, there are separate SDS-rich and Brij35-rich mixed micelles formed. In addition, NOESY spectra show that the interaction patterns of SDS and Brij35 in mixed micelles are similar for three systems, as are the solubilization sites of curcumin. Therefore, for α_SDS = 0.5 and 0.2 with single mixed micelles formed, the solubility of curcumin depends only on the mixed micelle composition, which is almost equal to the surfactant molar ratio. Although curcumin is solubilized in both separate micelles at α_SDS = 0.8, a less stable micelle structure may be responsible for the low solubility. This study provides new insights into the investigation and application of mixed micelle solubilization.     

用刚果红分光光度法测定阳离子表面活性剂

在弱酸性的HCl-NaAc缓冲介质中,某些阳离子表面活性剂(CS)与刚果红(CR)反应,形成离子缔合物时,刚果红发生褪色作用,最大褪色波长分别在510nm(CR-溴化十六烷基吡啶(CPB)体系)、514nm(CR-十六烷基三甲基溴化铵(CTAB)体系)。在最大褪色波长处,CS的浓度在0~4.16×10-5mol.L-1(CPB体系)、0~3.18×10-5mol.L-1(CTAB体系)范围内遵守比尔定律,表观摩尔吸光系数为1.62×104L/(mol.cm)(CPB体系)、1.72×104L/(mol.cm)(CTAB体系),检出限为9.78×10-7mol.L-1(CPB体系)、1.04×10-6mol.L-1(CTAB体系)。方法具有较高的灵敏度和良好的选择性,用于水样中CS的测定,结果满意。     

Synthesis and Evaluation of Some Schiff Base Surfactants for Treating Crude Oil Emulsions

Water soluble nonionic surfactants based on Schiff base monomers were prepared by their etherification with β,^` β- dichlorodiethylether and PEG 400 in presence of NaOH. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for synthetic water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 45°C and 60°C. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 90% and 100% at some concentrations.     

Ionic Complexes of Biotechnological Polyacids with Cationic Surfactants

Summary: Stoichiometric complexes of biotechnological poly(γ-glutamic) acid and poly(β,L -malic) acid with alkyltrimethylammonium surfactants of long alkyl chains could be readily prepared in aqueous medium. They adopt a biphasic layered structures in which the main chain and the side chain alternate with nanometric periodicity. Alkyl side chains show reversible melting that involves generation of mesophases. Complexes degraded by water by different mechanisms depending on the constitution of the main chain; the polymalic complexes underwent surface erosion whereas the polyglutamic ones degraded in bulk. Erythromycin could be homogenously loaded into the paraffinic subphase of the complexes and delivered upon incubation under physiological conditions in parallel to the hydrolysis of the polymer.     

UV–Spectral Study on the Effects of Inert Salts on the Nonionic Micellar Solubilization of Phenyl Salicylate in the Absence and Presence of a Cationic Surfactant Under Alkaline Aqueous Medium

The values of the fraction of ionizes phenyl salicylate, f_PS-, obtained from initial absorbance measurement of phenyl salicylate at 350 nm, remain unchanged with the increase in [CH₃CO₂Na] from 0.0 to 0.7 M at 0.01 M NaOH (f_PS- ≈ 0.70) and 0.02 M NaOH (f_PS- ≈ 0.93). The values of f_PS- decrease from ～ 1.0 to 0.90 and ～ 1.0 to 0.84 with the increase in respective [CH₃CO₂Na] and [NaBr] from 0.0 to 0.6 M at 0.01 M NaOH, 0.02 M C₁₂E₂₃(=C₁₂H₂₅(OCH₂CH₂)₂₃OH) and 0.01 M CTABr (=C₁₆H₃₃NMe₃Br).