Properties of Water/n-Propanol/Ionic Surfactant/Phenylacetylene Micellar Systems (original) (raw)
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Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
The effect of 1-alkanols viz., ethanol, 1-butanol and 1-hexanol on five quaternary salts based cationic surfactants in water and in presence of 0.1 M salts has been systematically investigated by viscosity and dynamic light scattering (DLS) technique. The concentration for surfactant varying in non-polar tail, polar head and counterion was kept constant (∼50 mM) throughout. The viscosity data are less detailed, but confirm the general trend of micellar growth and transitions. Influence of 1-butanol on critical micelle concentration (CMC) and degree of counterion dissociation (() was also investigated conductometrically. These measurements were done to supplement the role of counterions in exploring the binding phenomenon due to the effect of salt and alcohol during micellization. The effect of 1-alkanols upon the viscosity and micelle hydrodynamic diameter (D h ) of micelles in the presence of salt at varying concentration and temperature was also examined in detail to explain the hydrophobic interactions and electrostatic effects.
Characterization of Water/n-Propanol/Nonionic Surfactant/ Phenylacetylene Microemulsions
European Chemical Bulletin, 2013
Water/ n- propanol/nonionic surfactant / phenylacetylene micellar systems were formulated and used for the hydration of phenylacetylene . The ratio (w/w) of n- propanol/surfactant equals 2/1. The surfactants were sucrose laurate (L1695) and Marlipal 24/70 (M2470). The extent of the micellar region as function of temperature was determined. The particle hydrodynamic diameters of the oil-in-water micellar systems measured using dynamic light scattering and were found to decrease with temperature for sucrose laurate and to increase for Marlipal 24/70 based systems. In the diluted region microemulsion systems were observed. Highly efficient hydration of phenylacetylene was performed in these microemulsions. The reaction results indicate that hydration of phenylacetylene is more efficient when sucrose laurate was used for the formulation of the microemulsions
Colloid and Polymer Science, 2003
The effects of the addition of several propylene glycol oligomer additives on the micellar properties of the cationic mixed micelle system of cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) were investigated. Through conductivity studies, the critical micelle concentration (cmc) and counter-ion binding values were observed in the presence of the additives. A regular solution approach was employed to determine the effects of the additives on the interactions between the two surfactants to form the mixed micelles. The effects of the additives on the interaction parameter and the composition of the mixed micelles were evaluated. Excess Gibbs energy of mixing and the values of activity coefficients were also calculated and described in terms of non-ideality of the system.
Colloids and Surfaces A-physicochemical and Engineering Aspects, 2009
The formation of mixed micelles in cationic-nonionic (Dodecylpyridinium chloride (DPC)-Triton X-100) and anionic-nonionic (Aerosol OT (AOT)-Triton X-100) aqueous surfactant solutions has been studied at 25 • C both in the presence and absence of sodium butanoate (NaBu) and sodium hexanoate (NaHx). The critical micelle concentration (cmc) and free energy of micellization have been estimated through surface tension measurements. Composition, activity coefficients and mutual interaction parameters of mixed micelles were evaluated in terms of different theoretical models like that of Clint, Rubingh, Rodenas, Maeda and Blankschtein, that explain binary system well. The analysis reveals that, in spite of synergism, very small mole fraction of the ionic surfactant is present in the mixed micelles. Blankschtein model predicts a continuous decrease in synergism for the DPC + TX-100 system both in NaBu and NaHx due to their salt effect. On the contrary, Rubingh's treatment reveals an increase in synergism in the presence of NaHx above 30 mM as against a continuous decrease in NaBu in the whole concentration range. For the AOT + TX-100 system, where Blankschtein model is not applicable, Rubingh's treatment results in a continuous decrease in synergism in the presence of NaBu as well as NaHx.
The Journal of Physical Chemistry, 1985
Light scattering and photon correlation spectroscopy have been utilized in studying the effect of the surfactant chemical nature on micellar interactions in W/O microemulsions. Specifically, the surfactant chemical structure has been altered at the molecular level by adding a ramification near the polar head group. This influence of surfactant structure on micellar interactions has been examined through a series of five homologues of SDS, each variation containing a larger ramification. Analysis of the dispersed phase composition and of the light-scattering data indicates that the amphiphilic surface area occupied per surfactant molecule (including the alcohol contribution) is constant. The increase in the individual surfactant molecule polar head surface area is balanced by a decrease in the alcohol content of the interfacial film. As one proceeds through the SDS series, a definite decrease (from positive to largely negative) has been found for values of second virial coefficients. In terms of attractive potential, this indicates an evolution from hard spheres to largely attractive spheres.
Fluid Phase Equilibria, 2013
The aggregate structures and adsorption of anionic surfactant on interfacial region between water-hexane and-heptane as aliphatic hydrocarbons and-toluene as an aromatic hydrocarbon have been investigated by surface tension and conductometry at different electrolyte concentrations at different temperatures. Cyclic voltammetry and dynamic light scattering measurements have been used in order to explore the effect of aromatic hydrocarbons on the size of micellar aggregates. Also, the effect of hydrocarbons on particle size has been investigated. The presence of alkanes decreases the surface tension of water and the amount of adsorption of surfactant at interface of water-alkane. The values of free energy of adsorption are more negative than free energy of micelle formation, so in the presence of alkanes, the free energy of adsorption is affected more. In all systems and independent of the light phase, critical micelle concentration increases with rise of temperature due to breaking of water structure. Also, the results indicate a decreased adsorption with increase of temperature as molecular motions increase. However, free energy of micelle formation becomes more positive with the addition of salt.
Measurements of the conductance of binary mixtures of cetyltrimethylammonium bromide and sodium dodecylsulfate in pure water and in methanol-water mixed solvent media containing 0.10, 0.20, and 0.30 volume fractions of methanol at 308.15, 318.15, and 323.15 K are reported. The concentration of sodium dodecylsulfate varied from 0.001 to 0.04 molÁL -1 in the presence of *5.0 9 10 -4 molÁL -1 cetyltrimethylammonium bromide. The results showed a sharp increase in the conductance with increasing concentrations of the surfactant mixture. The conductance is found to increase with increasing temperature over the entire concentration range in pure water and in a given mixed solvent medium but is found to decrease with increasing methanol content in the solvent. Estimation of the pre-cmc (S 1 ) and post-cmc (S 2 ) slopes for the CTAB-SDS system, to calculate the critical micelle concentration, provides important insight regarding the solution behavior of the mixed surfactants. The critical micelle concentration (cmc) and degree of micellar dissociation (a) of sodium dodecylsulfate in the presence of cetyltrimethylammonium bromide increase in the methanol-water mixed solvent medium. Additionally, the values of cmc and a increase with increasing temperature. The thermodynamic functions for the micellization were calculated at various conditions.
Journal of Colloid and Interface Science, 2010
Micellization and micellar growth of cationic dimeric surfactants of the alkanedyil-a,x-bis(dimethyldodecylammonium) bromide type, 12-s-12,2Br À (s = 3, 4, 6), in the presence of various amounts of 1-butanol, 1pentanol, and 1-hexanol have been investigated. The influence of the nature and concentration of alcohol on the cmc, on the micellar ionization degree, on the average micellar aggregation number, and on the polarity of the micellar interfacial region was investigated by using conductivity and fluorescence measurements. Subsequently, effects of alcohol addition on the surfactant concentration range where sphere to rod transitions occur were examined and information about changes in the micropolarity and in the microviscosity accompanying the morphological transition was obtained. The experimental results were explained by considering the variations in the different contributions to the Gibbs energy of micellization caused by the presence of alcohols. The study of the reaction methyl naphthalene-2-sulfonate + Br À in some wateralcohol 12-6-12,2Br À micellar solutions provided information about the characteristics of the dimeric micelles as microreactors and show the complexity of the microheterogeneous systems studied.
Precise measurements on the specific conductivity of cationic surfactant (Dodecyltrimethylammonium Bromide) and anionic surfactant (Sodiumdodecyl Sulphate) in methanol-water mixed solvent media containing 0.1, 0.2 and 0.3 volume fractions of methanol are reported at 308.15 K. Specific conductivities of Dodecyltrimethylammonium Bromide and Sodiumdodecyl Sulphate increase with increase in concentration and decrease with increase in the volume fractions of methanol. Critical micelle concentration (cmc) increases with increase in volume fraction of methanol in case of both surfactants. Free energy of micellization (∆Gº m ) has been calculated. Increase in cmc with increase in volume fractions of methanol has been explained in terms of breaking of structure of water due to co-solvent effect.
PROPERTIES OF WATER/SODIUM DODECYL SULFATE/n-PROPANOL/ALLYLBENZENE MICELLAR SYSTEMS
European Chemical Bulletin, 2012
Water/n-propanol/sodium dodecyl sulfate/allylbenzene micellar systems were formulated. The ratio (w/w) of n-propanol/surfactant equals 2/1. The extent of the micellar region as function of temperature was determined. The micellar systems were characterized by the volumetric parameters, density, excess volume, ultrasonic velocity and isentropic compressibility. The micellar densities increase with the increase in the water volume fraction. Excess volumes of the sodium dodecyl sulfate decrease for water volume fraction below 0.3, stabilize for water volume fractions between 0.2 and 0.5 then increase for water volume fraction above 0.5. Excess volumes of the studied micellar systems increase with temperature. Ultrasonic velocities increase with the increase in water volume fraction up to 0.8 then decrease. Ultrasonic velocities increase with temperature for water volume fractions below 0.8 and increase for water volume fractions above 0.8. Isentropic compressibilities decrease with t...