Academic literature on the topic 'Synergistic mixtures of surfactants'

This paper presents a simple method for determination of synergism in binary surfactant mixtures. A homologous series of cationic alkyltrimethylammonium bromides (CnTAB, with n = 8, 12, 16, 18) mixed with three non-ionic surfactants (n-octanol, methyl isobutyl carbinol, tri(propylene glycol) butyl ether) was chosen as a model system. In addition to the cationic-non-ionic system, the mixture of anionic-non-ionic surfactants (sodium dodecyl sulphate and tri(propylene glycol) butyl ether) was investigated. The foam behavior of one-component solutions and binary mixtures was characterized as a function of surfactant concentration, number of carbons (n) in alkyl chain of CnTAB as well as type of surfactant. It was shown that synergism in foamability could be produced by the ionic-non-ionic systems, and the concentration below the synergism occurs, called the critical synergistic concentration (CSC), that can be easily predicted based on the surface tension data on individual components.

Abstract Solutions of sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine oxide (DDAO) with mole fractions of 0.00, 0.25, 0.50, 0.75 and 1.00 were prepared and their surface tension was measured as a function of total surfactant concentration. The critical micelle concentration (CMC) values of these mixed solutions were also determined. The minimum area occupied by a surfactant molecule at air/water interface was calculated for single and binary surfactant mixtures. A pronounced synergistic interaction between SDBS and DDAO was detected. The surface tension and CMC-values of SDBS/DDAO mixtures are significantly lower than those of the single surfactant. The mixed system of SDBS/DDAO exhibits a highly negative interaction parameter (β = −10.6) according to regular solution model, and is found to fulfill the condition of Hua and Rosen, indicting a strong synergistic interaction between the two surfactants. The contact angle measurements show the wettability of the surfactant mixture onto polyethylene substrate is higher than of the respective single surfactant. In addition, the adsorption of SDBS and DDAO or their mixtures on 1.0% activated carbon and 5.0% Jordanian natural clay (JNC), respectively, was investigated using the depletion method. The individual surfactants were found to adsorb to a considerable extent on activated carbon, and a slightly higher adsorption tendency was even measured for mixed SDBS/DDAO surfactant systems. Although no SDBS molecules adsorbed on JNC, adsorption was observed for solutions containing DDAO and SDBS/DDAO surfactants. The improvement in wettability and adsorption of SDBS/DDAO surfactants at the air/water and solid/water interfaces is directly related to the synergistic interaction between the two surfactants.

The influence of various adjuvant combinations on the uptake of glyphosate was examined using a model grass species, wheat. Compared with each of 6 surfactants used alone, a greater uptake enhancement was observed when an aliphatic amine surfactant of higher ethylene oxide (EO) content was mixed with either a linear alcohol or an octylphenol non-ionic surfactant of lower EO content, at equivalent concentration. Surfactant ratio in a mixture was also important in the case of one combination. Three of the positive surfactant combinations were also tested on barnyard grass and their synergistic effect on glyphosate uptake was confirmed. The performance of one of the best surfactant combinations was further compared with a commercial glyphosate formulation by measuring the uptake rate of glyphosate into both wheat and ryegrass plants over a 24-h period. The surfactant mixture provided much faster uptake into both species and also significantly higher overall uptake into ryegrass. Whereas ammonium sulfate could also improve glyphosate uptake into wheat when used at high concentrations and in combination with certain non-ionic surfactants, the enhancing effect of a humectant, glycerol, on uptake was of much lower magnitude and observed only in the presence of super-spreading surfactants. The practical value of using surfactant mixtures is discussed.

Objectives. To create stable artificial polymer suspensions with a positive charge of particles based on polycarbonate and polymethyl methacrylate using cationic surfactants and organosilicon surfactants.Methods. The size of droplets and polymer suspension particles was determined by photon correlation spectroscopy (dynamic light scattering) using a Zetasizer NanoZS laser particle analyzer (Malvern, UK).Results. Domestic cationic surfactants Katamin-AB and Azol-129 were found to be capable of producing stable artificial polycarbonate and polymethyl methacrylate suspensions. Based on the polymer, the optimal surfactant concentration was 6 wt %. The effect of polymer concentration in solution on the stability and particle size of final polymer suspensions was shown. It was determined that the polymer concentration in the solution should not exceed 10%. When obtaining a highly dispersed suspension during dispersion, a higher concentration causes an increase in the viscosity of emulsions. As a result of a synergistic effect formation, we used mixtures of cationic surfactants (Katamin-AB/Azol-138 and Azol-129/Azol-138) to enhance the stability of the final polymer suspensions. The optimal surfactant ratio was 9:1. The total concentration of the mixture is 10 wt %, based on the polymer. Polymer suspensions were stabilized with each of 2:1 mixtures of cationic surfactants Katamin-AB and Azol-129 withan organosilicon surfactant U-851. The total mixture concentration was 9 wt %, based on the polymer.Conclusions. New methods of producing artificial polycarbonate and polymethyl methacrylate suspensions in the presence of domestically produced cationic surfactants, as well cationicorganosilicon surfactants mixtures, were proposed. The colloidal-chemical properties of the obtained polymer suspensions were considered. It was found that using a 2:1 mixture of cationic and organosilicon surfactants produces polymer suspensions that are stable during production and storage.

This study investigated the solubilization capabilities of rhamnolipids biosurfactant and synthetic surfactant mixtures for the application of a mixed surfactant in surfactant-enhanced remediation. The mass ratios between Triton X-100 and rhamnolipids were set at 1:0, 9:1, 3:1, 1:1, 1:3, and 0:1. The ideal critical micelle concentration values of the Triton X-100/rhamnolipids mixture system were higher than that of the theoretical predicted value suggesting the existence of interactions between the two surfactants. Solubilization capabilities were quantified in term of weight solubilization ratio and micellar-water partition coefficient. The highest value of the weight solubilization ratio was detected in the treatment where only Triton X-100 was used. This ratio decreased with the increase in the mass of rhamnolipids in the mixed surfactant systems. The parameters of the interaction between surfactants and the micellar mole fraction in the mixed system have been determined. The factors that influence phenanthrene solubilization, such as pH, ionic strength, and acetic acid concentration have been discussed in the paper. The aqueous solubility of phenanthrene increased linearly with the total surfactant concentration in all treatments. The mixed rhamnolipids and synthetic surfactants showed synergistic behavior and enhanced the solubilization capabilities of the mixture, which would extend the rhamnolipids application.

The uptake of glyphosate into wheat and two grass species in the presence of surfactants varied with surfactant structure, ethylene oxide (EO) content and concentration. A synergistic uptake enhancement into wheat and barnyard grass was observed when an aliphatic amine surfactant was mixed with either an alcohol or octylphenol nonionic surfactant with different EO content, at equivalent concentration. The effect of an amine+alcohol surfactant mixture on glyphosate uptake into wheat and ryegrass was compared with commercial glyphosate formulations.

The focus of the present work is to evaluate the interactions of an anti-allergic drug (diphenhydramine hydrochloride, DPH) with anionic (sodium dodecyl sulfate, SDS) and cationic (cetylpyridinium chloride, CPC) surfactants in the aqueous medium. The mixed micellization behavior and surface properties of drug-surfactant mixtures have been examined by surface tension measurements. Various theoretical approaches were applied to explore the synergistic or non-ideal behavior of the current mixed systems. Furthermore, the binding studies of drug with surfactants have been elaborated by UV–visible spectroscopy. Benesi–Hildebrand (B-H) theory was used to compute stoichiometric ratio, binding constant, and free energy change for the drug-surfactant mixtures. The outputs are deliberated taking into consideration the use of surfactants as capable drug delivery agents for DPH and hence advance bioavailability.

Biotechnology is one of the fastest growing sector of scientific and applied activities of the humans, which needs to be successfully integrated into existing technologies. Such upcoming trend is the combination of conventional pulp treatment by surfactants and enzymatic processing in order to prevent pitch troubles in the pulp and paper mills. This article presents the research results of the abilities of non-ionic surfactants (sintamid-5, sintanol DS-10), enzyme (lipase) and their syner-gistic combinations to the micelle formation and solubilization. We chose the optimal synergistic compositions and investigated their colloid-chemical characteristics. There is no effect to the micelle formation ability of surfactants when addition of lipase is up to 30%. The largest deviation from the additive values of surface activity was observed for the mixture of individual non-ionic surfactant and lipase at the ratio of 70:30. However, in the all mixtures of both surfactants and lipase the ratio of experimental surface activity to the theoretically calculated is less than one. It looks, that hydrophilic areas of mixed aggregates block hydrophobic areas of lipase thereby preventing adsorption of lipase at the interface. A predominance of the surfactant in the composition will reduce its cost. The maximum of solubilizing capacity has sintanol DS-10 due to its highest HLB and the lowest CMC that leads to more micelles amount in solution and higher total hydrocarbon volume. The pitch solubilization in lipase solutions does not depend on enzyme concentration. The high pitch dissolving in synergistic mixture of sintanol DS-10 and lipase is observed. It is predetermines the usage of such systems for cellulose deresination.For citation:Smith R.A., Demyantseva E.Yu. Andranovich, O.S. Impact of lipase on micelle formation and solubilization abilities of non-ionic surfactants. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 54-60

Solubilities of pyridine-2-azo-p-dimethylaniline ( pada ) were determined at 25�C in four mixed fluorocarbon/hydrocarbon short-chained surfactant systems: ( i ) sodium decyl sulfate/sodium perfluoroheptanoate; (ii) sodium octanesulfonate /sodium perfluorooctanoate ; (iii) sodium octanesulfonate /sodium perfluoroheptanoate ; (iv) sodium nonanesulfonate /sodium perfluoroheptanoate. Systems ( i ), (iii) and (iv) showed micellar miscibility (one mixed micelle) and synergistic solubilization effects. System (ii) had two critical micelle concentrations pointing to two micellar forms in solution, and no synergism could be detected. From these four examples, it is deduced that single mixed micelles are formed when the critical micelle concentrations of the pure surfactants are within a factor of 3 of each other.

In drug delivery, surfactants are used to reduce side effects and to increase drug efficiency. The present work aimed to study the interaction of diphenhydramine hydrochloride (anti-allergic drug) with TX–45 (non-ionic surfactant) in the absence and presence of ionic liquid (1-hexyl-3-methylimidazolium chloride). The physicochemical parameters were estimated by the surface tension measurement. Various theoretical models (Clint, Rubingh, Motomura, and Maeda) were applied to determine the attractive behavior between drug and surfactant mixtures at the surface and in bulk. The drug and surfactant mixtures exhibit synergistic behavior in the absence and presence of ionic liquid. Several energetic parameters were also estimated with the assistance of regular solution approximation and pseudo phase separation model that indicate micelle formation and adsorption of surfactant at the surface is thermodynamically advantageous. The morphology of pure and mixture of amphiphiles has been estimated by the Tanford and Israelachvili theories. UV-visible spectroscopy was used to quantify the attractive behavior of the drug with surfactant with the help of a binding constant (K).

Робота виконана на кафедрі хімії і хімічної технології Національного авіаційного університету Міністерства освіти і науки України.
Дана робота присвячена розробці технологічних рідин на основі створення синергічних сумішей інгібіторів корозії і ПАР для електроіскрового механічного методу підготовки сталевих поверхонь за допомогою електричних шліфувальних машин. Антикорозійна ефективність синергічних сумішей пасиваторів оксидної і сольової дії залежить від природи компонентів, механізму їх дії, а також від співвідношення молярних концентрацій складових в синергічних сумішах. Результати поляризаційних досліджень електрохімічної поведінки сталі показали перевагу інгібуючої ефективності синергічних композиції порівняно з ефективністю окремих компонентів, що підтверджується наявністю зони пасивації в широкому діапазоні потенціалів (0,8-1 В) і мінімального значення густини струму повної пасивації (1-2*10^-6 А/см^2), що свідчить про повний захист сталі від корозії. Показано, що зниження поверхневого натягу водних розчинів створених сумішей ПАР на межі повітря - рідина і зниження мікротвердості сталі на межі рідина-метал мають подібний характер. Введення розроблених технологічних рідин в зону обробки дозволяє знизити енергетичні витрати процесу на 30-40%, і підвищити клас чистоти поверхні на 3 і більше одиниць за рахунок ефекту пластифікації поверхні (ефект Ребіндера). Електроіскрова обробка оцинкованою щіткою дозволяє наносити на поверхню металу цинкові протектори, які разом з синергічними сумішами інгібіторів виявляють явище нададитивності, забезпечують майже стовідсотковий антикорозійний захист сталі навіть в сильно агресивних середовищах (3% NaCl), і збільшує період післяопераційного зберігання. Особливо високі показники захисту сталевих поверхонь отримано при використанні оцинкованої щітки з наступним нанесенням лакофарбового покриття, де реалізуються ефект взаємного посилення (синергізму) між протекторним електрохімічним захистом з лакофарбовим покриттям.

Робота виконана на кафедрі хімії і хімічної технології Національного авіаційного університету Міністерства освіти і науки України
Дана робота присвячена розробці технологічних рідин на основі створення синергічних сумішей інгібіторів корозії і ПАР для електроіскрового механічного методу підготовки сталевих поверхонь за допомогою електричних шліфувальних машин. Антикорозійна ефективність синергічних сумішей пасиваторів оксидної і сольової дії залежить від природи компонентів, механізму їх дії, а також від співвідношення молярних концентрацій складових в синергічних сумішах. Результати поляризаційних досліджень електрохімічної поведінки сталі показали перевагу інгібуючої ефективності синергічних композиції порівняно з ефективністю окремих компонентів, що підтверджується наявністю зони пасивації в широкому діапазоні потенціалів (0,8-1 В) і мінімального значення густини струму повної пасивації (1-2*10^-6 А/см^2), що свідчить про повний захист сталі від корозії. Показано, що зниження поверхневого натягу водних розчинів створених сумішей ПАР на межі повітря - рідина і зниження мікротвердості сталі на межі рідина-метал мають подібний характер. Введення розроблених технологічних рідин в зону обробки дозволяє знизити енергетичні витрати процесу на 30-40%, і підвищити клас чистоти поверхні на 3 і більше одиниць за рахунок ефекту пластифікації поверхні (ефект Ребіндера). Електроіскрова обробка оцинкованою щіткою дозволяє наносити на поверхню металу цинкові протектори, які разом з синергічними сумішами інгібіторів виявляють явище нададитивності, забезпечують майже стовідсотковий антикорозійний захист сталі навіть в сильно агресивних середовищах (3% NaCl), і збільшує період післяопераційного зберігання. Особливо високі показники захисту сталевих поверхонь отримано при використанні оцинкованої щітки з наступним нанесенням лакофарбового покриття, де реалізуються ефект взаємного посилення (синергізму) між протекторним електрохімічним захистом з лакофарбовим покриттям.
The work is devoted to the development of process fluids based on synergistic mixtures of surfactants and corrosion inhibitors for the electric-spark mechanical method steel surfaces preparing using electric grinders. The use of individual representatives of inhibitors and surfactants usually does not allow to obtain high efficacy. More effective are mixtures, the composition of which is characterized by a synergism in the action of their components. Nowadays, studies devoted to elucidating the mechanism of action of highly effective synergistic mixtures of metal corrosion inhibitors and surfactant compositions, same as related to the uncertainty of if effectiveness influence on the nature of components, as well as concerning the ratio of their concentrations in solutions remain developed insufficiently. The influence of additives on the qualitative characteristics of the prepared surfaces and energy costs of the process are also studied insufficiently. Such situation requires to develop research aimed on the increasing the corrosion resistance of metals during their postoperative period of storage, and also on improving of its protective properties after the paints and varnishes application. To prevent an occurrence of corrosion processes during electrospark machining of steel, technological fluids specifically containing synergistic mixtures of corrosion inhibitors with different mechanism of action oxide and salt passivation or adsorption were developed, their effectiveness depends on the ratio of components and is characterized by an extremum where attained maximum level of inhibitory effect of additives on the kinetics of electrochemical corrosion processes of steel and full protection is achieved. Anticorrosive efficiency of synergistic mixtures of the passivator oxide action (sodium nitrite) and the salt action (sodium silicate) depend on the nature of the components, the mechanism of their action, and also on the ratio of its molar concentrations constituting in synergistic mixtures and is characterized by a synergistic extremum of inhibitory action at a ratio of sodium nitrite concentrations and sodium silicate, as 1:2. The results of polarization studies of the electrochemical behavior of steel have revealed an advantage of the inhibitory efficiency of the synergistic compositions compared to the efficiency of individual components, and is confirmed by the existence of a passivation zone in a wide range of potentials (0.8-1 V) and by minimum values of the full passivation (1-2*10^-6 A/cm^2) current density, which indicates the comprehensive corrosion protection of steel. The introduction of such process fluids into the processing zone allows the treatment energy costs reducing by 30–40% and increasing the surface cleanliness class by 3 and more units due to the surface plasticization effect (Rehbinder effect). Synergistic mixtures of surfactants contain molecules with oppositely charged functional groups, between which the forces of mutual attraction arise that allows to achieve high surface activity at the phase boundaries: air - liquid and liquid - metal. It was found that a decrease of the surface tension in aqueous solutions of the developed surfactant mixtures at the air-liquid interface and a decrease in the microhardness of steel at the liquid-metal interface have a similar nature and demonstrate efficiency extremes with a similar ratio of molar concentrations of anionic and cationic active components of order 1:1. The thermodynamic characteristics of the formation of an adsorption layer surfactant at the interface of the aqueous solution-air were determined. It is shown that the dependences of surface tension, changes in entropy and enthalpy on the ratio of molar concentrations of cationic and anion active surfactants have a parallel extreme character, and the positive value of ΔS> 0 indicates that the driving force of the direct adsorption process is the entropy factor. The electro-spark treatment with a galvanized brush allows to apply zinc protectors to the metal surface, which, together with the synergistic mixtures of inhibitors, demonstrate the phenomenon of additivity and provide almost one hundred percent corrosion protection of steel even in strong corrosive media (3% NaCl), and enlarges the period of postoperative storage. Especially high rates of steel surfaces protection are obtained using a galvanized brush with the subsequent application of a paint and varnish coating, where the effect of mutual reinforcement (synergism) between the sacrificial electrochemical protection with a paint coating is realized. Due to the formation of zinc hydroxide inside the paint coating, the ohmic resistance is enlarged, the adhesion and protective properties of paint coatings are improved.

The equilibrium phase behaviour of ternary mixtures of water, oil and surfactants is examined using both a lattice-gas model and a Ginzburg-Landau model. The lattice model is based on the Blume-Capel model with additional orientational degrees of freedom for surfactants, and the Ginzburg-Landau model is based on two local scalar fields. When the concentrations of water and oil are equal the following phases are observed: a water and oil rich phase, a lamellar phase, and a disordered phase which is divided into an ordinary disordered fluid and a microemulsion region. In the lattice model, a square phase is also observed. The effects of fluctuations on the lattice model is studied via Monte-Carlo simulations and by the Langevin approach in the Ginzburg-Landau model. In both cases, we found that in the vicinity of the water/oil coexistence region, the lamellar phase becomes unstable against the microemulsion.
Furthermore, we have studied the effects of surfactants on the dynamics of phase separation of two immiscible fluids, and found a drastic alteration in the kinetics. In particular, we found that surfactants slow down the growth to a non-algebraic one leading eventually to a microphase separation.

We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade
, Rovral&trade
, Terminator&trade
and Teldor&trade
at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade
significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.

A widely accepted model in obtaining the mixed micelle composition is Rubingh's thermodynamic model, in which CMC data from surface tension and conductivity measurements of mixed surfactant solutions are used to calculate compositions of mixed micelles. The validity of this model has not been previously challenged. In this study, the behaviour of binary mixtures of an anionic; sodium dodecylsulfate (SDS) and a cationic; dodecyltrimethyl ammonium bromide (DTAB) with non-ionic surfactants; N -dodecyl-N ,N -di mcthyl-3-ammoni o-l-prop