Binary Surfactant Research Articles

Synergistic Interaction between Nonionic Octylphenol Polyoxyethylene Ethers and Effect of Hydrophilic Chain

AbstractThe micellization of binary mixture composed of nonionic octylphenol polyoxyethylene ether (OP‐n, n is the average number of oxyethylene unit) and its homologues, as well as the effect of hydrophilic chain were investigated. The tensiometry was adopted to determine the critical micelle concentration of binary surfactant mixture. According to the regular solution theory, some thermodynamic models were used to predict the parameters of micellization and the thermodynamic parameters. For all the three binary mixtures of nonionic/nonionic surfactants, each of which shows a nonideal mixing and can behave synergistically in aqueous solution. For both the mixture of OP‐10/OP‐7 and the mixture of OP‐10/OP‐4, the positive deviation of the mole fraction of surfactant in mixed micelle from its ideal value coexists with the negative deviation in the entire range of compositions in aqueous solution, while for the mixture of OP‐7/OP‐4, it only shows a positive deviation. Thermodynamic data indicate that for all the three binary surfactant mixtures, the process of micellization is entropically spontaneous, and the change of hydrophilic chain results in the difference in the stability of mixed micelle. The results can be explained by the steric effect, the hydrogen bonding and the hydration. The work helps with understanding the interaction between molecules and properties for some industrial products constituted by nonionic surfactant and its homologues.

Pengaruh Surfaktan Biner Cetil Trimetil Amonium Bromida (CTAB)- Hexametilen Triamin (HMT) pada Pembentukan Perak Nanorods menggunakan Katalis Natrium Hidroksida

Nanoparticles have different physical properties and more interesting than that of bulk material. Nanoparticles are highly preferred for applications in various technologies as a catalyst, the raw material of electronic components, and as an antimicrobial agent. The aim of the research is synthesize of silver nanorods. The effect of a binary surfactant CTAB-HMT on the morphology and homogeneity were investigated using UV/Vis spectrophotometer, TEM, and XRD. Base on the UV/Vis spectra and TEM morphology, silver nanoparticles have two types, spherical and rods shapes. The best product of nanorods was obtained at the composition of CTAB 0.15 M : HMT 0.15 M. The structure of nanorods obtained were face center cubic (fcc).

Development of Nanoemulsion of Silicone Oil and Pine Oil Using Binary Surfactant System for Textile Finishing

AbstractNanoemulsions of silicone oil and pine oil using a binary surfactant system were prepared. Silicone oil and pine oil were used to achieve softness and mosquito repellency and antibacterial activity respectively when the nanoemulsion was applied on the fabric. A silicone surfactant (AG‐pt) and a hydrocarbon surfactant (TDA‐6) were used in different proportions to obtain stable nanoemulsions at the lowest possible droplet size. The various emulsification process variables such as ratio of hydrocarbon to silicone surfactant, surfactant concentration, ratio of silicone oil to pine oil, oil weight fraction and sonication time have been studied. The optimal variables include the ratio of hydrocarbon to silicone surfactant of 80:20, surfactant concentration of 8%, ratio of silicone oil to pine oil of 80:20, oil weight fraction of 20% and 15 min of sonication time at 40% of the applied power. Nanoemulsions were found to be very stable with emulsion droplet size around 41 nm. In order to compare different emulsification techniques, emulsions were also prepared using the conventional method. Emulsions analyzed using SEM showed spherical droplets ranging from 40 to 120 nm. Atomic force microscopy was used to evaluate the bounciness, fluffiness and softness of fabric. From this study, it was found that stable nanoemulsion with a lowest possible droplet size of silicone and pine oil could be prepared by ultrasonic emulsification technique in order to deliver multiple properties when applied to fabric.

Shape tunable synthesis of anisotropic gold nanostructures through binary surfactant mixtures

In recent years, much effort has been made to produce gold (Au) nanorods of different sizes through the use of binary surfactant mixtures via a seed-mediated growth approach. However, how the ratio of two different surfactants influences the shape of the resulting Au nanoparticles remains to be elucidated. Here, we report the shape-controlled synthesis of Au nanoparticles using a binary surfactant mixture of CTAB (cetyltrimethylammonium bromide) and DDAB (didodecyldimethylammonium bromide) via a silver-assisted seed-mediated growth approach. Decreasing the CTAB/DDAB ratio results in a shape transition from Au nanorods to elongated tetrahexahedra and finally to Au bipyramids. The results showed significant improvement in the yield of Au bipyramidal type nanoparticles in different sizes (nm to μm) by using binary surfactant mixtures without any need for shape selection procedure. By varying the pH and concentration of ascorbic acid, we can control the shape and size of Au nanoparticles (i.e., truncated bipyramids, dogbones, and nanodumbbells) at fixed CTAB/DDAB ratios. A preliminary growth mechanism has been proposed based on the change in the mixed micelle soft-template induced by the increasing concentration of DDAB and reaction parameters (i.e., pH, concentration of ascorbic acid). These results constitute the advances in the understanding for synthesizing anisotropic Au nanoparticles of tunable optical properties via engineering the design of a soft-template. These anisotropic Au nanoparticles, especially, bipyramids of different morphologies and sizes are potential candidates for the enhancement of the optical response and developing label-free biosensing devices.

Experimental study on surface activity of surfactants on their ability to cleaning oil contaminations

In order to obtain a recipe for an effective degreasing agent, a selection of suitable surfactants is required. The present investigation addresses essentially the determination and comparison of the static and dynamic adsorption as well as wetting properties of selected surfactants and their binary mixtures which are potential components of the degreasing compositions. Equilibrium surface/interfacial tension in the air/water system for individual compounds and their binary mixtures were measured by du Nouy ring method. Moreover, the interfacial properties of binary surfactant mixtures with different polarity were investigated. The experimentally obtained isotherms: surface tension of the air/water systems and interfacial tension of oil/water systems for all investigated surfactants allowed to compare the surface activity of compounds considered. Surface and micellar properties of surfactants and their mixtures were discussed on the basis of equilibrium surface tension measurements and the study of kinetics of adsorption. The Rosen theory was used to characterize the synergism effects observed in the case of systems with binary surfactant mixture. The results indicated that the studied compounds reveal both different efficiency as well as different effectiveness of adsorption in the air/water system. Some of analysed binary surfactant mixtures show strong synergistic effects in lowering the surface tension and in the wettability of solid surfaces. The wetting properties of considered compounds strongly depend on the character of wetting surface. The dynamics of adsorption in considered systems is significantly affected by the concentration of surfactant solution. Generally, the efficiency of lowering surface tension is significantly higher in the micellar solutions. The results obtained allow to select mixture of nonionic surfactant and amphoteric one as potential components of the degreasing compositions.

Hexadecyltrimethylammonium bromide (CTA-Br) and 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF4) in aqueous solution: An ephemeral binary system

HypothesisMixtures of the cationic surfactant hexadecyltrimethylammonium bromide (CTA-Br) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF4) in aqueous solutions are expected to behave as typical binary cationic surfactant system taking into account the surface activity displayed by the ionic liquid, instead of considering the IL as a water cosolvent. ExperimentsSurface tension and conductivity measurements have been conducted as a function of the total concentration of the mixtures at different surfactant mole fraction (αCTA-Br) to investigate the surface active properties. FindingsTurbidity immediately appearing when the compounds are mixed in water suggests the spontaneous formation of the low soluble compound hexadecyltrimethylammonium tetrafluoroborate (CTA-BF4), together with the salt formed by the respective counterions bmim+and Br− in solution. For αCTA-Br≠0.5, furthermore of the mentioned compounds, the spare bmim-BF4 (for αCTA-Br<0.5) or CTA-Br (for αCTA-Br>0.5), are also present in the aqueous solution. Systems containing excess of bmim-BF4 show a low critical aggregate concentration (cac), but an unexpected high surface tension at cac (γcac≈53–56mN/m), as pure CTA-BF4. For systems containing excess of CTA-Br, cac increases but γcac decreases up to 36mN/m. Mixtures of pure CTA-BF4 and bmim-BF4 or CTA-Br behave as typical binary surfactant systems.

Synthesis of mesoporous silica materials (MCM‐41) using silica fume as the silica source in a binary surfactant system assisted by post‐hydrothermal treatment and its Pb2+ removal properties

AbstractMesoporous silica materials (MCM‐41) were successfully prepared by substituting silica fume for silicate in different surfactant systems. The effects of binary surfactant systems and post‐hydrothermal treatment on the morphology and structural properties of MCM‐41 were investigated based on X‐ray diffraction (XRD), N2 sorption/desorption, and transmission electron microscopy analyses (TEM). The results confirmed that polyethylene glycol (PEG‐6000) is an effective additive template in a binary surfactant system for the synthesis of mesoporous silica materials. Meanwhile, the hydrothermal stability of the mesoporous silica materials can be improved by post‐hydrothermal treatment and the optimal experimental parameters are a temperature of 140 °C and a treatment time of 48 h. The formation of high‐quality MCM‐41 is based on the balance between the ordered assembly of the inorganic anionic species and cationic surfactant, in accordance with the electrostatic interactions and hydrogen bonds between PEG‐6000 and the inorganic species. Meanwhile, Pb(II) removal from aqueous solution has also been examined using MCM‐41 as an adsorbent. The results of adsorption showed that the as‐synthesized MCM‐41 demonstrated a high capacity of Pb2+.

Influence of working fluids on startup mechanism and thermal performance of a closed loop pulsating heat pipe

Development of efficient cooling system is a tricky and challenging task in the field of electronics. Pulsating heat pipe has a great prospect in the upcoming days for an effective cooling solution due to its excellent heat transfer characteristics. Experimental investigations are reported on a Closed Loop Pulsating Heat Pipe (CLPHP). The influence of working fluids on startup mechanism and thermal performance of a CLPHP are carried out on 2mm, nine turn copper capillary. Total eleven (11) working fluids are prepared and investigated. Deionized (DI) Water (H2O), ethanol (C2H6O), methanol (CH3OH) and acetone (C3H6O) are used as pure fluids. The water-based mixture (1:1) of acetone, methanol and ethanol are used as binary fluids. Sodium Dodecyl Sulphate (SDS, NaC12H25SO4) is used as a surfactant to prepare the water-based surfactant solutions of 30PPM, 45PPM, 60PPM and 100PPM. The filling ratio is kept as 50%. The vertical bottom heating position of a CLPHP is considered. Heat input is varied in the range of 10–110W. Significant influence is observed for water-based binary fluids and surfactant solutions on startup mechanism and thermal performance of a CLPHP compared to DI water used as the pure working fluid.

Binary mixed micelles of triton X-100 and selected bile salts: Thermodynamic stabilization and pKa values of micellar bile acids

Bile acid anions are biosurfactants which form small micelles. To enhance the hydrophobic volume of the micelle, bile salts are used as mixed micelles with non-ionic surfactants. Micellar-bound bile acids (sodium-hyodeoxycholate, HD and sodium-cholate, C in binary mixed micelles with non-ionic surfactant Triton X-100) at concentration of 10cmc have higher pKa values than bile acids from the aqueous solution. Different pKa values of micellar and non-micellar bile acids (ΔpKa) are due to the excess Gibbs energy GHAE which is a function of interaction coefficient and mole fraction of Triton X-100 in the binary surfactant mixture. In the mixed micelles ΔpKa values show synergistic interactions between different building units, similarly as interaction coefficient.

Sulfonated methyl esters, linear alkylbenzene sulfonates and their mixed solutions: Micellization and effect of Ca2+ ions

Here, we compare the properties of sulfonated methyl esters of fatty acids (SME) and linear alkylbenzene sulfonate (LAS) with respect to the effect of calcium ions on their surface tension and the effect of their mixing on the critical micelle concentration (CMC). The theoretical interpretation of surface tension isotherms obtained in the presence of NaCl and CaCl2 allowed us to determine the parameters that characterize the surfactant adsorption layers and counterion binding. The excluded area per molecule in the adsorption layer is the same for SME and LAS, and is determined by the cross-sectional area of the sulfonate headgroup. The binding energy of Na+ ions to the headgroups of SME and LAS is also the same. However, the binding energy of the Ca2+ ion to the headgroup of LAS is considerably greater than that of SME in agreement with the circumstance that LAS is precipitated by hard water. In contrast, the binding energy of the Ca2+ ion to the headgroup of SME is lower even than that of Na+, in accord with the reputation of SME as one of the most hard-water tolerant surfactants. The dependencies of the CMC on the composition of binary mixed surfactant solutions reveal that C14-SME and C16-SME exhibit ideal mixing; C14-SME and LAS – slightly synergistic mixing, whereas C16-SME and LAS – antagonistic mixing due to hydrocarbon-chain mismatch. The micellization in mixed solutions of SME and cocamidopropyl betaine has been also investigated. The results in the present study allow prediction of the surface tension of solutions of SME and LAS in the presence of Na+ and Ca2+ ions at various concentrations; contribute for a better understanding of the different tolerance of SME and LAS to hard water, and quantify the effect of their mixing on the CMC.

The Thermodynamic Properties of Dynol-604/AOT Mixed Reverse Micelles in Isooctane

The volumetric properties of the mixed surfactants bis(2-ethylhexyl) sodium sulfosuccinate and ethoxylated-2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (Dynol-604) at various compositions in isooctane have been studied by density measurements at 303.15 K. The apparent specific volumes and the critical reverse micelle concentrations of the binary mixed surfactants were determined. The results were used to calculate the compositions, excess properties of mixing, activity coefficients and the interaction parameter between the two surfactants in the mixed micelles, based on Rubingh’s formalism.

Growth Mechanism of Gold Nanorods in Binary Surfactant System

In order to reveal the growth mechanism of gold nanorods (GNRs) in a binary surfactant system, we synthesized various GNRs by changing the concentration of the surfactants, AgNO3 , and HBr in the growth solution. We found that the benzyldimethylhexadecylammoniumchloride surfactant had weak interaction with the gold ions, but it could reduce the membrane fluidity. In addition, we could dramatically decrease the cetyltrimethylammonium bromide concentration required for GNR growth by adding an HBr solution. Notably, Ag+ ions were necessary to break the symmetry of the seed crystals for GNR growth, but increasing the concentration of Ag+ and Br− ions caused a decrease in the template size.

Adsorption of anionic and non-ionic surfactants on carbon nanotubes in water with dissipative particle dynamics simulation.

The morphology of surfactants physically adsorbed on the surface of carbon nanotubes (CNTs) has a significant impact on the dispersion of CNTs in the solution. The adsorption of the surfactants alfoterra 123-8s (AF) and tergitol 15-s-40 (TG) on CNTs was investigated with dissipative particle dynamics (DPD) simulations, as well as the behavior of the binary surfactant system with CNTs. Properties of surfactants (i.e., critical micelle concentration, aggregation number, shape and size of micelle, and diffusivity) in water were determined to validate the simulation model. Results indicated that the assembly of surfactants (AF and TG) on CNTs depends on the interaction of the surfactant tail and the CNT surface, where surfactants formed mainly hemimicellar structures. For surfactants in solution, most micelles had spherical shape. The particles formed by the CNT and the adsorbed surfactant became hydrophilic, due to the outward orientation of the head groups of the surfactants that formed monolayer adsorption. In the binary surfactant system, the presence of TG on the CNT surface provided a considerable hydrophilic steric effect, due to the EO groups of TG molecules. It was also seen that the adsorption of AF was more favorable than TG on the CNT surface. Diffusion coefficients for the surfactants in the bulk and surface diffusion on the CNT were calculated. These results are applicable, in a qualitative sense, to the more general case of adsorption of surfactants on the hydrophobic surface of cylindrically shaped nanoscale objects.

Influence of heat on miscibility of Quillaja saponins in mixtures with a co-surfactant

Thermal treatment of mixed surfactant systems can have a major impact on their phase behavior through modified interactions between the surfactants. In this study, we investigated the miscibility behavior of aqueous binary surfactant systems composed of Quillaja saponin extract and sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin at different concentration ratios (0–5% w/v) at pH3, 5, and 7 upon heat treatment (25–75°C). The results revealed that the heat-treated Quillaja saponin–sodium caseinate mixtures at pH7 remained miscible when the ratio of Quillaja saponins was equal or higher to the ratio of caseinate, otherwise the mixtures flocculated due to increased hydrophobic interactions. At pH3, the aggregation of Quillaja saponin–sodium caseinate structures was intensified by heating mainly through self-association of casein molecules. In Quillaja saponin–pea protein mixtures as well as in pure pea protein samples heating led to weakening of the gel structures at all tested pH values. In contrast, heating did not affect Quillaja saponin–rapeseed lecithin mixtures, which stayed miscible independent of pH due to electrostatic repulsive forces. Furthermore, the flocculated (pH5, 7) or aggregated (pH3) Quillaja saponin–egg lecithin mixtures were only slightly affected by heating. These results are important for understanding the interactions of binary surfactant systems when subjected to heating, which is a common processing step in many food applications.

Steady-state fluorescence investigations of aqueous binary mixtures of myristyl alcohol based bis-sulfosuccinate anionic gemini surfactant and effect of different conventional surfactants therein

ABSTRACTThe present research work is associated with the fluorescence investigations of binary aqueous mixed surfactants solutions of anionic bis-sulfosuccinate gemini surfactant (BSGSMA1,8) and three different conventional surfactants—anionic viz. sodium dodecyl sulfate (SDS), cationic viz. cetyl trimethyl ammonium bromide (CTAB), and nonionic surfactant viz. Triton X 100. Steady-state fluorescence spectroscopy technique has been utilized to examine the micellization behavior of aqueous solution of pure myristyl alcohol-based BSGSMA1,8 having flexible methylene chain [(CH2)8] as spacer group. Critical micelle concentration (CMC), aggregation number (N), and micropolarity of pure and mixed surfactants systems were explored during the investigations. The results revealed the best synergism behavior of prepared gemini BSGSMA1,8 with SDS as compared to CTAB and Triton X 100. The maximum reduction in the value of pyrene intensity ratio (I1/I3) was observed for gemini and SDS mixed surfactant solution. On the other hand, the increased I1/I3 value of mixed gemini with Triton X 100 exhibited that mixed surfactant system of anionic gemini BSGSMA1,8 with non-ionic Triton X 100 is not as compact as other mixed surfactant systems. Aggregation number increased and micropolarity decreased with increased concentration of gemini surfactants.

Synthesis of Long Gold Nanorods as an Efficient Photothermal Agent in the Second Near-Infrared Window

To date, intensive efforts have been devoted in the synthesis of various nanomaterials as photothermal agent in the first near-infrared (NIR) window (650-950 nm). Although the NIR-II window (1000-1350 nm) is recognized to offer more efficient tissue penetration and higher permissible exposure to excitation light, the corresponding photothermal agents have been scant. Here, we report a binary surfactant seeded growth method for high yield synthesis of long AuNRs (LAuNRs) as an efficient NIR-II photothermal agent. The as-synthesized LAuNRs with aspect ratio of 6.7 shows strong surface plasmon resonance band at 1064 nm, and demonstrates high photothermal conversion efficiency and excellent photothermal stability. When the AuNRs aqueous dispersion is covered with a 6 mm thick pork tissue as a model of biological tissues, its temperature can still be increased by 13.1 °C under a 1064 nm 1.0 W/cm2 laser irradiation. These results demonstrate the promising potential of the LAuNRs as an efficient photothermal agent in the NIR-II window.

Enhanced aqueous solubility of polycyclic aromatic hydrocarbons by green diester-linked cationic gemini surfactants and their binary solutions

Three homologues of a novel biodegradable diester-linked cationic gemini surfactant series, CmH2m+1 (CH3)2N+(CH2COOCH2)2N+(CH3)2CmH2m+1.2Cl− (m-E2-m; m = 12, 14, 16), were used for investigation of the solubilization of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene and pyrene in single as well as binary surfactant solutions. Physicochemical parameters of the pure/mixed systems were derived by conductivity and surface tension measurements. Dissolution capacity of the equimolar binary surfactant solutions towards the PAHs was studied from the molar solubilization ratio (MSR), micelle–water partition coefficient (Km) and free energy of solubilization (ΔGs0) of the solubilizates. Influence of hydrophobic chain length of the dimeric surfactants on solubilization was characterized. Aqueous solubility of the PAHs was enhanced linearly with concentration of the surfactant in all the pure and mixed gemini–gemini surfactant systems.

Errata: ‘Synthesis of gold nanorods with longitudinal surface plasmon resonance wavelength up to 1245 nm using gallic acid as a reductant in the presence of a binary surfactant system’

Errata: ‘Synthesis of gold nanorods with longitudinal surface plasmon resonance wavelength up to 1245 nm using gallic acid as a reductant in the presence of a binary surfactant system’

Properties of Binary Surfactant Mixtures of Anionic Gemini Surfactant and Amphoteric Surfactant

Abstract The surface tension of the mixed system of linear alkylated diphenylmethane sulfonate and amphoteric surfactant didodecylmethylcarboxyl betaine along with their different combinations has been investigated in 0.1 M salt solutions at 313 K. The surface chemical parameters of the mixture were also calculated. The results show that the critical micelle concentration (CMC) and γCMC of the mixture are always lower than those of the individual surfactants, which indicates synergistic effects between the surfactant molecules. The interfacial tension of the Chinese Shengli crude oil and the connate water can be reduced to 5 × 10−3 mN · m−1 at 70°C with the mixture of alkylated diphenylmethane sulfonate and didodecylmethylcarboxyl betaine.

Complex Behavior of Bile Salts (SC and SDC) at Various Temperatures under the Influence of Tricyclic Antidepressant Drug (Imipramine) in Aqueous Solution

Objective: The present method was based on the effect of bile salt (Sodium Cholate (SC) and Sodium Deoxycholate (SDC)) on the dissolution of Antidepressant drug like Imipramine. SC and SDC is a type of anionic surfactants form mixed micelle with Imipramine and influence its rate of dissolution. The micellization behaviour of binary anionic bile salt surfactant mixtures was investigated by conductivity method and various thermodynamical parameters are calculated. The results of the study have been analyzed by using Clint’s, Rubingh’s, and Motomura’s theories for mixed binary systems. Method: The Critical Micelle Concentration (CMC) of the binary mixtures (Bile salt and Drugs) were studied using conductivity measurements, at different mole fractions and different temperatures. Results: The micellization behaviour of binary anionic surfactant and drug mixtures was investigated by conductivity CMC, extent of counter ion binding (α), thermodynamic parameters (ΔG°m, ΔH°m, ΔS°m) and various parameters like cmcid, xid, X1 and the β parameter for micellization process have been reported and discussed. Conclusion: The thermodynamic parameters of the process of micellization have been calculated for each system. ΔG°m is negative and becomes less negative with increase in concentration. This suggests the micellization formation is becomes less spontaneous with increasing temperatures. The entropy of micellization is positive indicated that the micellization process is somewhat entropy dominated.