Thermodynamics of non-ionic surfactant Triton X-100-cationic surfactants mixtures at the cloud point

This study investigates the effects of gemini and conventional cationic surfactants on the cloud point (CP) of the non-ionic surfactant Triton X-100 (TX-100) in aqueous solutions. Instead of visual observation, a spectrophotometer was used for measurement of the cloud point temperatures. The thermodynamic parameters of these mixtures were calculated at different cationic surfactant concentrations. The gemini surfactants of the alkanediyl-α-ω-bis (alkyldimethylammonium) dibromide type, on the one hand, with different alkyl groups containing m carbon atoms and an ethanediyl spacer, referred to as “m-2-m” (m = 10, 12, and 16) and, on the other hand, with –C₁₆ alkyl groups and different spacers containing s carbon atoms, referred to as “16-s-16” (s = 6 and 10) were synthesized, purified and characterized. Additions of the cationic surfactants to the TX-100 solution increased the cloud point temperature of the TX-100 solution. It was accepted that the solubility of non-ionic surfactant containing polyoxyethylene (POE) hydrophilic chain was a maximum at the cloud point so that the thermodynamic parameters were calculated at this temperature. The results showed that the standard Gibbs free energy , the enthalpy and the entropy of the clouding phenomenon were found positive in all cases. The standard free energy increased with increasing hydrophobic alkyl chain for both gemini and conventional cationic surfactants; however, it decreased with increasing surfactant concentration.     

Micelle-mediated cloud point extraction and spectrophotometric determination of rhodamine B using Triton X-100

A new micelle-mediated cloud point extraction method is described for sensitive and selective determination of trace amounts of rhodamine B by spectrophotometry. The method is based on the cloud point extraction of rhodamine B from aqueous solution using Triton X-100 in acidic media. The extracted surfactant rich phase is diluted with water and its absorbance is measured at 563 nm by a spectophotometer. The effects of different operating parameters such as concentration of surfactant and salt, temperature and pH on the cloud point extraction of rhodamine B were studied in details and a set of optimum conditions were obtained. Under optimum conditions a linear calibration graph in the range of 5-550 ng mL⁻¹ of rhodamine B in the initial solution with r = 0.9991 (n = 15) was obtained. Detection limit based on three times the standard deviation of the blank (3S_b) was 1.3 ng mL⁻¹ (n = 10) and the relative standard deviation (R.S.D.) for 50 and 350 ng mL⁻¹ of rhodamine B was 2.40 and 0.87% (n = 10), respectively. The method was applied for the determination of rhodamine B in soft pastel, hand washing liquid soap, matches tip and textile dyes mixture samples.     

Kinetics,mechanism and cloud point measurements in the oxidative degradation of non-ionic Triton X-100 surfactant in acidic permanganate solutions

The polyoxyethylene chain of non-ionic surfactant Triton X-100 [4-(1,1,3,3-tetramethylbutyl) phenyl polyethylene glycol,TX-100] was degraded by permanganate in the presence of HClO₄. The oxidative degradation rate and cloud point have been obtained as a function of [surfactant], [permanganate], [HClO₄], and temperature. Dependence of the reaction rate on adding inorganic salts (Na₄P₂O₇, NaF and MnCl₂) was also examined. The oxidation rate increased with increase in [TX-100] and [H⁺]. The higher order kinetics with respect to [TX-100] at lower [H⁺] shifted to lower order at higher [H⁺]. The cloud point of TX-100 (67°C) shifted to lower temperature (23±0.5°C) after oxidative degradation of the polyoxyethylene chain. Evidence of complex formation between TX-100 and MnO ₄ ⁻ was obtained spectrophotometrically. Presence of the primary alcoholic (–OH) group in the TX-100 skeleton is responsible for the degradation of oxyethylene chain. Both monomeric and aggregated TX-100 molecules are oxidized by permanganate. A catalytic oxidation mechanism is proposed on the basis of the experimental findings.     

Role of the nonionic surfactant Triton X-405 in emulsion polymerization. I. Homopolymerization of styrene

The emulsion polymerization of styrene was studied using the nonionic surfactant Triton X-405 (octylphenoxy polyethoxy ethanol). Two separate nucleation periods were noted in these polymerizations resulting in bimodal final latex particle size distributions. The partitioning of the surfactant between the phases was found to play the major role in determining the nucleation mechanism(s) in these polymerizations. Although the total concentration of the emulsifier was always added at a level above its critical micelle concentration (CMC) based on the water phase in the recipe, it was found that the portion of the surfactant initially present in the aqueous phase was below its CMC due to the partitioning. This CMC was also found to increase with increasing total surfactant because the distribution of the surfactant (varying ethylene oxide chain length) depended on the partitioning between the phases. Under these conditions, the first of the two nucleation periods was attributed to homogeneous nucleation, while the second was attributed to micellar nucleation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3813–3825, 1997     

Spectrophtometric determination of malachite green in fish farming water samples after cloud point extraction using nonionic surfactant Triton X-100

A novel and sensitive cloud point extraction procedure for the determination of trace amounts of malachite green by spectrophotometry was developed. Malachite green was extracted at pH 2.5 mediated by micelles of nonionic surfactant Triton X-100. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 630 nm. The effect of different variables such as pH, Triton X-100 concentration, cloud point temperature and time and diverse ions was investigated and optimum conditions were established. The calibration graph was linear in the range of 4-500 ng mL⁻¹ of malachite green in the initial solution with r = 0.9996 (n = 10). Detection limit based on three times the standard deviation of the blank (3S_b) was 1.2 ng mL⁻¹ and the relative standard deviation (R.S.D.) for 20 and 300 ng mL⁻¹ of malachite green was 1.48 and 1.13% (n = 8), respectively. The method was applied to the determination of malachite green in different fish farming and river water samples.     

有机酸对非离子型表面活性剂浊点的影响

有机酸对非离子表面活性剂TritonX-100浊点的影响与酸的亲水性能、空间效应及其在胶束中的增溶位置有关。直链一元酸的加入均使浊点下降,且酸的碳链越长影响越大。直链二元酸对TritonX-100浊点下降的影响小于直链一元酸,且碳原子数nc<6时,使得浊点略有升高;nc≥6时,使得浊点下降。由于空间位阻作用,支链酸和取代酸使TritonX-100浊点降低幅度较小。     

Influence of alcohols on the lower consolute behavior and thermodynamic approach of Triton X-114 aqueous two-phase systems

The addition of foreign material to surfactants shows the change in temperature at which the clouding process occurs. This work evaluates the impact of n-alcohols on Cloud Point (CP) of nonionic surfactant Triton X-114 at variable concentrations. It was found that the CP of pure Triton X-114 shows concentration-dependent variation. The presence of lower alcohols improves CP value whereas the addition of higher alcohols brings down CP with variation as concentration increases. These effects can be clarified in view of the site of the impact of molecular design of added substances on the stability of micelle organization. The foaming ability and foam stability data are also used to discuss the stability of micellar accumulation. Considering CP as a threshold temperature of the solubility, the thermodynamic parameters of the clouding process ΔG⁰_cl, ΔH⁰_cl, and ΔS⁰_cl, have been assessed, using the “Phase Separation Model”. The outcomes of the work demonstrate that the clouding phenomenon of Triton X-114 is an exothermic and non-spontaneous process.     

Role of Cloud Point of the Capping Agent (Nonionic Surfactant,Triton X-100) on the Synthesis of Silver Nanoparticles

The solution behavior of the nonionic surfactants below and above the cloud point (CP) is quite different. Below CP, a single phase of molecular or micellar solution exists, whereas above the CP, the solution separates into two phases: the first one is denser and smaller phase and contains most of the surfactant and the other one is relatively a voluminous aqueous phase and has surfactant concentration close to the critical micelle concentration (cmc). There are many reports available where nonionic surfactant is used as capping agent. But, to the best of our knowledge, there is no report on the CP's role on the synthesis of nanoparticles (NPs). Therefore, it is very important to understand the role of the CP on the synthesis of NPs. In the present work, we report the role of the clouding of the nonionic surfactant Triton X-100 (using as capping agent) on the synthesis of AgNPs below and above the CP. The morphology of AgNPs was studied by transmission electron microscopy (TEM), dynamic light scattering (DLS), UV–Vis absorption, etc., techniques. Below the CP, spherical polydisperse particles of 12 ± 5 nm mean diameter were found, whereas above the CP, the aggregated particles with higher diameter were found.     

The Micellization and Clouding Phenomena of a Nonionic Surfactant,Poly(ethylene glycol) t-octylphenyl ether (Triton X-100): Effect of (Chloride Salt) Electrolytes

Herein, we report the micellization and the clouding of a nonionic surfactant, poly(ethylene glycol) t-octylphenyl ether (Triton X-100), in aqueous solutions in the absence and presence of (chloride salt) electrolytes. In the absence and presence of electrolytes, the critical micelle concentration (CMC) of Triton X-100 was measured by surface tension measurements. Upon increasing the temperature as well as the concentration of electrolytes, the CMCs decreased. The surface properties and the thermodynamic parameters of the micellar systems were evaluated. From these evaluated thermodynamic parameters, it was found that in the presence of an electrolyte, the stability of the micellar system is high. The cloud points (CPs) of Triton X-100 were also measured in the absence and presence of metallic ions of electrolytes. Upon the addition of metallic ions of chloride salts (electrolytes), the decrease in CP values was observed and the order was found to be: K⁺ > Na⁺ > Li⁺ > NH⁺₄.     

Influences of Triton X-100 micelle on the microstructure of HSA

The effects of Triton X-100 molecule and micelle on the microstructure and properties of HSA are studied by the some methods of UV spectrum, fluorescence spectrum, fluorescence polarization, circular dichroism, conductivity, and zeta potential. With the increase of Triton X-100 concentration, the UV absorbance, fluorescence intensity of HSA, and the system conductivity all first decrease and then increase. The zeta potential of HSA first goes up and then down. The percents of the β-sheet, random, turn structures, and the polarization of HSA increase but the percent of the α-Helix of HSA decreases. When Triton X-100 concentration is more than 1.0×10⁻³ mol l⁻¹, the structure parameters change obviously especially for the percents of random and turn structures.     

Influences of Triton X-100 on Hemoglobin Behaviors in Hemoglobin/Acyclovir/Triton X-100/H2O System

The influences of Triton X-100 on hemoglobin （Hb） behaviors were studied by the methods of UV-Vis spectrum, fluorescence spectrum, HPLC, conductivity, zeta potential and negative-staining transmission electron microscope in Hb/acyclovir/Triton X-100/H2O system. With the increase of Triton X-100 concentration in the system, the percentage of the free acyclovir increased from 58%--63% to 90%--94%. The static quenching constant and the association number of acyclovir to Hb decreased. The fluorescence spectrum, conductivity, zeta potential, fluorescence polarization and negative-staining morphology of Hb tended to recover to those of the original state of Hb in the same concentration of Hb. The interaction between Triton X-100 and Hb is stronger than that between acyclovir and Hb. Most Triton-X-100 was associated with Hb at low Triton X-100 concentration. But the interaction of Triton X-100 with Hb was apparently dominant in high Triton X-100 concentration. The Hb structure was unfolded and finally denatured.     

TritonX-100-5-Br-PADAP光度法测定发样中铁

在表面活性剂Triton X-100存在下,以5－Br-PADAP作显色剂,光度法测定发样中铁,结果在所选浓度范围内线性关系良好,稳定时间长,回收率平均为98．14％。     

Dynamic surface tensions of micellar Triton X-100 solutions

Considering surfactant solutions at concentrations exceeding the CMC, another relaxation process besides diffusion occurs, also affecting the dynamic surface tension. The latter equilibration process concerns a micellisation/demicellisation process, representing the disintegration of micelles into monomers. The micellisation kinetics are accounted for by adding a single source term to the diffusion equation of the free monomers.

In the present paper the integration of the diffusion equation is avoided by using the concept of the diffusion penetration depth. Nevertheless, when this approximation is made, good agreement is achieved between experiment and theory for micellar Triton X-100 solutions. Moreover, it follows that diffusion of micelles may not be neglected.     

AOT/Triton X-100混合反胶束体系中假丝酵母脂肪酶催化蓖麻油水解的活性

研究了二(2-乙基己基)琥珀酸磺酸钠(AOT)/Triton X-100混合反胶束体系中假丝酵母脂肪酶(candida rugosa lipase)催化蓖麻油水解的反应. 考察了Triton X-100占总表面活性剂的摩尔分数(x(Triton X-100))、水与总体表面活性剂的摩尔比(ω0)、pH值、反应温度以及底物蓖麻油的浓度等因素对酶活性的影响. 研究结果表明, 加入非离子表面活性剂Triton X-100可以使假丝酵母脂肪酶的活性得到显著提高, 但是当底物蓖麻油的浓度大于0.24 mol·L-1时, 会对假丝酵母脂肪酶产生抑制作用.     

The effects of various foreign substances on the cloud point of Triton X 100 and Triton X 114

The nonionic surfactants Triton X 100 and Triton X 114 form isotropic micellar solutions around 25°C. One of the characteristic features of these solutions is the fact that at higher temperatures they undergo clouding and liquid-liquid phase separation. Addition of various additives to the surfactant solutions does change the temperature at which the clouding phenomenon occurs. In this paper such effect of additives on the clouding phenomenon of Triton X 100 and Triton X 114 are discussed.     

Selective cloud point extraction and preconcentration of trace amounts of silver as a dithizone complex prior to flame atomic absorption spectrometric determination

Dithizone (diphenylthiocarbazone) was used as a complexing agent in cloud point extraction for the first time and applied for selective preconcentration of trace amounts of silver. The analyte in the initial aqueous solution was acidified with sulfuric acid (pH<1) and Triton X-114 was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with tetrahydrofuran (THF) and the analyte determined in the enriched solution by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, a preconcentration factor of 43 was obtained for only 10 ml of sample. The analytical curve was linear in the range of 3-200 ng ml⁻¹ and the limit of detection was 0.56 ng ml⁻¹. The proposed method was applied to the determination of silver in water samples.     

Triton X-100在乙二醇中的胶体性质

表面活性剂在非水溶剂中聚集态的研究所见的报导与水体系相比要少得多．然而近年来对非水体系的研究日益增多．这是因为表面活性剂在非水溶剂中的应用日趋增加，但与水体系相反，对非水体系的性质了解甚少．对表面活性剂非水体系的研究还有助于对其聚集体的共溶剂效应有更深的认识．TritonX－100（以下简写为TX－100）是典型的非离子表面活性剂，在工业上有着广泛的应用．乙二醇在多醇中与水的化学结构最相近问，然而它却是水结构的破坏剂，加入少量的乙二醇会使水的冰点急剧下降．乙二醇又是蛋白质的变性溶剂．表面活性剂在乙二醇中的胶…     

Spectrophotometric determination of cloud point of Brij 35 nonionic surfactant

The cloud point of nonionic surfactant polyoxyethylene (23) lauryl ether (Brij-35) was determined in the presence of various inorganic electrolytes. The measurements of cloud point (CP) were carried out with UV-vis spectrophotometer instead of visual observation. CP of Brij-35 could not be measured directly because its CP is more than 100 °C. Therefore, CP values of Brij-35 were lowered by the addition of electrolytes. In this study, NaF, NaCl, NaBr, KNO₃, K₂CO₃, K₃PO₄, Li₂SO₄, Na₂SO₄, K₂SO₄, (NH₄)₂SO₄, CuSO₄, ZnSO₄, CoSO₄ were used as electrolytes. Linear lines which were drawn with CP values were extrapolated to zero electrolyte concentration. The real CP value of Brij-35 which is merely listed as >100 °C in the literature was found as 118.5 ± 0.5 °C for all samples. Furthermore, the effects of the nature of the cation and the anion and the valencies of the cations on CP were reported and the rate of decrease in CP with concentration is discussed.     

头孢唑酮与Triton X-100缔合体系的相互作用

抗生素头孢唑酮的加入使得非离子表面活性剂Triton X-100的表面活性降低. ¹H-NMR的结果表明，头孢唑酮增溶于胶束极性基团附近.头孢唑酮与Triton X-100胶束的结合常数随Triton X-100含量的增加而下降，但头孢唑酮在Triton X-100胶束相和水连续相之间的分配系数不随Triton X-100含量变化而变化.     

Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry

The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in the presence of 0.1% Triton X-114 and 2 × 10⁻⁴ mol L⁻¹ 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL⁻¹ silver. The calibration graph was linear in the range of 10–200 ng mL⁻¹, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples.