Hexaethylene Glycol Dodecyl Ether Research Articles

Critical thickness of foam films stabilized by nonionic, ionic surfactants and their mixtures

Abstract The critical thickness (hcr) for foam films of n-dodecyl β-D maltoside (C12G2) and of its mixed solutions with dodecanol (C12Е0), hexaethyleneglycol dodecyl ether (C12E6) and dodecyl trimethylammonium bromide (C12TAB) of different molar ratio (50:1; 1:1;1:50) at low and high ionic strength was measured interferometrically. It was found that the hcr increases with the increase of the film radius independently of solutions composition. At low ionic strength the type of surfactant affects the critical thickness and the equilibrium state of the film. hcr for the films of mixture with C12E0 increases with the increase of the total surfactant concentration, while hcr for the films of mixture with C12TAB decreases. For the values of the critical thicknesses for films from individual surfactant solutions the following sequence hcr (C12TAB) > hcr (C12E6) > hcr (C12G2) is found. At high ionic strength the quantity of nonionic additive does not substantially affect the value of hcr, while the quantity of ionic additive influences it by two different ways (i) in 50:1 mixture C12TAB supports C12G2 in the reducing of negative charge; (ii) in 1:1 mixture C12TAB recharges the film surfaces.

Critical thickness of foam films stabilized by nonionic or ionic surfactants and their mixtures

The critical thickness (hcr) for foam films of n-dodecyl β-D maltoside (C12G2) and of its mixed solutions with dodecanol (C12Е0), hexaethylene glycol dodecyl ether (C12E6) and dodecyl trimethylammonium bromide (C12TAB) of different molar ratios (50:1; 1:1;1:50) at low and high ionic strength was measured interferometrically. It was found that hcr increases with an increase in the film radius, regardless of the solution’s composition. At low ionic strength the type of surfactant influences substantially the value of hcr. At high ionic strength the level of nonionic surfactant does not in fact influence the value of the critical thickness, while the effect of an ionic surfactant may be significant, in accord with its molar ratio in the mixture: (i) C12TAB in the 50:1 molar ratio mixture acts as a minor additive and supports C12G2 in reducing of negative charge; the values of hcr for films from the mixture are lower than those from solution of C12G2 alone; (ii) at a molar ratio 1:1C12TAB has a dominant role, so it recharges the film surfaces and the hcr values of films from the mixture are higher.The measured critical thicknesses hcr(exp) have been juxtaposed with the calculated ones hcr (cal) by the approaches of Vrij, Radoev-Scheludko-Manev (RShM) and Coons. In two of the cases, the experimentally determined drainage coefficient α has been used. The comparison has shown that the combination of RShM equation with α firmly improves the correlation between hcr(exp) and hcr(cal). Good agreement between hcr(exp) and hcr(cal) for films of low surfaces coverage was achieved by introducing an additional, non-DLVO attraction force.

Formation Mechanism Studies of Phenylene-Bridged Periodic Mesoporous Organosilicas (PMOs)

The formation of phenylene-bridged periodic mesoporous organosilicas (PMOs) in the presence of three diblock copolymers differing in hydrophobic hydrocarbon chain lengths was investigated. Hexaethylene glycol octadecylether (C(18)(EO)(6)), hexaethylene glycol hexadecylether (C(16)(EO)(6)), and hexaethylene glycol dodecylether (C(12)(EO)(6)) were chosen in order to obtain insight on the influence of the hydrocarbon chain length on the mesostructure. 1,4-Bis(triethoxysilyl)benzene (BTEB) was used as organosilica precursor under mild acidic conditions. The reactions were followed by in situ small-angle X-ray diffraction (SAXD) on-time in a capillary flow setup. It was found that during the reaction the formation of different structures was observed, which is ascribed to the hydrolysis and condensation of the organosilica precursor. In all cases, different structures evolve with time and phase transitions are observed during the measurements independent of the hydrocarbon chain length.

Binary mixtures of (β-C12G2) with cationic and non-ionic surfactants: micelle and surface compositions.

Surfactants used for practical applications are usually surfactant mixtures because they often exhibit a performance that is superior to the individual surfactants. In the present study binary mixtures of the sugar based surfactant n-dodecyl-β-D-maltoside (β-C12G2) with the cationic surfactant dodecyl trimethylammonium bromide (C12TAB) and the non-ionic hexaethylene-glycol dodecyl ether (C12E6), respectively, were investigated at different bulk mole fractions. Surface tension measurements were used to determine the critical micelle concentration and the surfactant composition at the surface. In addition, the regular solution theory was used to calculate interaction parameters as well as the mole fractions of the individual surfactants in the mixed air-water monolayer and in the mixed micelles, respectively. It was found that n-dodecyl-β-D-maltoside interacts weakly with the cationic surfactant (C12TAB) and that it dominates in both the mixed monolayer and the mixed micelles. On the other hand, β-C12G2 and C12E6 mix ideally in solution. For both surfactant mixtures the surfactant composition at the surface determined by surface tension measurements and by the regular solution theory, respectively, were compared and discussed in detail.

Response of Surface‐Plasmon Resonance Sensor Based on Gold Surfaces Modified by Self‐Assembled Monolayer to Nonionic Surfactants

A chemical sensor for the determination of nonionic surfactants (NISs) based on surface‐plasmon resonance (SPR) phenomenon was fabricated using a gold thin film, the surface of which was modified with a self‐assembled monolayer (SAM). Stearylmercaptan was used for the SAM constituent. The magnitude of the angle shift of SPR sensor to NISs increases in this order: Triton X‐100<heptaethyleneglycol dodecyl ether (HEEG)<hexaethyleneglycol dodecyl ether (HEG)<pentaethyleneglycol dodecyl ether (PEG). This order of magnitude of angle shift is in accord with the sequence of the hydrophobicity of the NISs. The linear relationships between Δθ (the change in the resonance angle relative to the baseline value) and the concentration of NISs were obtained in the concentration range from 2×10−6 M to 1×10−5 M. The coexistence of common inorganic cations and anions at 100 times excess to the Triton X‐100 gives only a positive error less than ca. +5%. The coexistence of an anionic surfactant (sodium dodecylbenzene sulfonate) at 10 times excess to the Triton X‐100 gives a very serious positive error of ca. +320%. This serious positive error was completely eliminated by using the flow system with an anion‐exchange resin column.

Phase diagram for self-assembly of amphiphilic molecule C 12E 6 by dissipative particle dynamics simulation

In a previous study, dissipative particle dynamics simulation was used to qualitatively clarify the phase diagram of the amphiphilic molecule hexaethylene glycol dodecyl ether (C 12E 6). In the present study, the hydrophilicity dependence of the phase structure was clarified qualitatively by varying the interaction potential between hydrophilic molecules and water molecules in a dissipative particle dynamics (DPD) simulation using the Jury model. By varying the coefficient of the interaction potential x between hydrophilic beads and water molecules as x = − 20 , 0 , 10 , and 20, at a dimensionless temperature of T = 0.5 and a concentration of amphiphilic molecules in water of ϕ = 50 % , the phase structures grew to lamellar ( x = − 20 ), hexagonal ( x = 0 ), and micellar ( x = 10 ) phases. For x = 20 , phase separation occurs between hydrophilic beads and water molecules.

Supramolecule Structure for Amphiphilic Molecules by Dissipative Particle Dynamics Simulation

Meso-scale simulation of structure formation for AB-dimers in solution W monomers was performed by dissipative particle dynamics (DPD) algorithm. As a simulation model, modified Jury Model was adopted [Jury, S. et al. “Simulation of amphiphilic mesophases using dissipative particle dynamics,” Phys. Chem. Chem. Phys. 1 (1999) 2051–2056], which represents mechanics of self-assembly for surfactant hexaethylene glycol dodecyl ether (C12E6) and water (H2O). The same phase diagram as Jury's result was obtained. We also found that it takes a longer time to form the hexagonal phase (H1) than to form the lamellar phase (Lα).

X-ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

Structural parameters for the free-standing foam film of hexaethylene glycol monododecyl ether (C12E6) have been measured by using X-ray reflectometry. The results indicate that a “five-laminae” model corresponds to this inverted bilayer and divides it into five regions. The thicknesses of the aliphatic chain regions, the polar head-group regions, and the central aqueous core are 0.90, 1.35 and 1.31 nm, respectively; and their corresponding electron densities are 2.4 × 10−3, 2.6 × 10−3 and 2.3 × 10−3 electron/nm3, respectively; the interfacial roughness between adjacent regions is 0.34 nm. The central core of this foam film does not contain free water, its thickness decreased 0.40 nm under the irradiation of infrared rays due to the loss of structural water.

Ostwald Ripening of Alkane in Water Emulsions Stabilized by Hexaethylene Glycol Dodecyl Ether

The Ostwald ripening and the solubilization of alkane in water emulsions stabilized by the nonionic surfactant hexaethylene glycol n-dodecyl ether (C12E6) were investigated. For emulsions prepared under high-shear conditions in a microfluidizer, the presence of micelles swollen by alkane hardly affects the ripening rate. For already formed emulsions to which extra surfactant solutions were added, the ripening rates increased slightly with increasing added surfactant concentration. The ratio of the highest to the lowest observed ripening rate is no more than a factor of 3. The main aging mechanism is the transport of alkane by molecular diffusion through the continuous phase. This mechanism is confirmed by the temperature dependence of the ripening rate. The solubilities and the solubilization rates of different alkanes in several surfactants were determined. The solubilization rates of different alkanes are approximately proportional to their solubilities in micellar surfactant solution and are dependent ...

X-ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

X-ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

Aqueous Phase Behavior of Hexaethylene Glycol Dodecyl Ether Studied by Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and 13C NMR Spectroscopy

The phase behavior of aqueous mixtures of a nonionic surfactant, hexaethylene glycol dodecyl ether (C12E6), was investigated by means of differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and 13C nuclear magnetic resonance (13C NMR) spectroscopy. The T−X phase diagram of this system was constructed from the DSC results. Comparison of the phase diagram with those previously obtained for C12E7 and C12E8 demonstrates that with the decrease in the polyoxyethylene (POE) chain length, the region of Lα phase expands toward higher temperature, whereas the H1 region shrinks toward lower temperature. This behavior is well explained in terms of the change in the critical packing parameter of the surfactant molecules associated with the change in the POE chain length. FT-IR results indicate that the ordered conformational structure of both the hydrocarbon and POE chains is kept after the transformation from solid to mesophases. The order-to-disorder transformation of the conformational structure of the chains takes place rather gradually within mesophases with the increase in temperature. This behavior of the chain melting associated with the temperature rise is common to aqueous mixtures of POE-type nonionic surfactants. 13C NMR line widths depend strongly on the phase structure formed by this mixture system: quite broad signals are observed for H1 and Lα phases, whereas the signals for V1 phase are rather sharp. According to the two-step model for NMR relaxation in aqueous surfactant systems, the line broadening observed in H1 and Lα phases is attributed to the anisometry of the molecular assemblies in these phases.

Physicochemical properties of resorcinol-type calix[4]arenes phosphoric esters having four alkyl side chains in aqueous solution

The physicochemical properties of phosphate esters of resorcinol-type of calix[4]arenes([4]Ar5P-R n ; side chain length n=6, 8, and 12) in aqueous solutions have been characterized by several techniques including surface tension and NMR. It is found that the critical micelle concentrations (cmcs) of [4]Ar5P-R n are insensitive against the alkyl side chain length, whereas the polarity of aggregates remarkably depends on the alkyl side chain length. From static light scattering and NMR measurements it is suggested that the shapes of aggregates of [4]Ar5P-R n are not globular and the alkyl side chains of [4]Ar5P-R n gather loosely in the aggregates. The mixed properties of [4[Ar5P-R 12 and hexaethyleneglycol dodecylether have also been investigated. The mixed cmcs are considerably greater than those of the respective surfactant cmcs and the interaction parameter calculated using a modified regular solution theory is +2.7. These results indicate that the repulsive interactions occur in the mixed micelles.

Phase behavior of mixed polyoxyethylene-type nonionic surfactants in water

Abstract Cloud temperatures, phase behavior, and the structures of liquid crystals were investigated in the aqueous systems of homogenous hexaethylene glycol dodecyl ether(C 12 EO 6 ) and mixed C 12 EO 4 -C 12 EO 8 , C 12 EO 2 -EO 8 , C 12 EO 2 -C 12 EO 8 , and C 12 EO 0 -C 12 EO 8 In the mixed surfactant systems, the average polyoxyethylene- (EO-) chain lengths are kept constants, the same as C 12 EO 6 . The change in cloud temperatures is small in all the systems, whereas the phase behavior is successively changed with increasing the difference in EO-chain length in the mixture. Lamellar liquid crystal is developed in the phase diagrams and it intrudes in the two-phase region above the cloud temperature. Hence, the phase pattern of the present mixed surfactant systems resembles that of C 12 EO 5 system, but both cloud point and W+L α region appear at much higher temperature. Hence, the Hydrophile-Lipophile Balance of the surfactant is not largely changed by mixing the surfactants but the SAXS results show that the surfactant molecules are more tightly packed in the hexagonal and lamellar phases by mixing. It is considered that when surfactants of different EO-chain lengths are mixed, the considerable reduction in repulsion between the hydrophilic moieties takes place and the surfactant molecules are more tightly packed.

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The solubilization of hydrocarbon and fluorocarbon alcohols in single and mixed aqueous solutions containing fluorocarbon surfactant has been studied. Surfactants used are lithium dodecyl sulfate (LiDS), lithium perfluorooctane sulfonate (LiFOS), lithium perfluorooctanoate (LiPFO), and hexaethyleneglycol dodecyl ether (6ED). In single surfactant systems, the partition coefficients of the alcohols between anionic micelles and water are greater for the surfactants which have the same kind of alkyl chain as the alcohols than for the surfactants having a different kind of alkyl chain to the alcohols. The standard free energies calculated from the partition coefficients indicate that the transfer of the alcohols occurs more favorably to the micelles consisting of the same kind of alkyl chain as the alcohols than of the different kind of alkyl chain. Also, the mixed surfactant systems LiDS-LiFOS, LiFOS-LiPFO and 6ED-LiFOS have been characterized by the regular solution parameter β and the alcohol partition coefficient. In the LiDS-LiFOS system with a positive β value, the partition coefficients of both hydrocarbon and fluorocarbon alcohols are greater than in single surfactant systems. In the LiFOS-LiPFO system exhibiting almost ideal mixing, the partition coefficients of both hydrocarbon and fluorocarbon alcohols change ideally, whereas the partition coefficients of the fluorocarbon alcohols are greater than those of the hydrocarbon alcohols. By contrast, in the 6ED-LiFOS system with negative β values, the partition coefficients of both alcohols are lower than in single surfactant systems.

Identification of transitions in lyotropic mesophases in hexaethylene glycol dodecyl ether–water by precision densimetry

The temperature dependence of the density has been measured for several concentrations of the hexaethylene glycol dodecyl ether (C12E6)–water (H2O) system, which exhibited lyotropic mesophases. The transitions from the lamellar (Lα) phase to the micellar solution (L1) phase and from the hexagonal (H1) phase to the micellar solution phase are of first order, and the molecular packing in the Lα phase is closer than that in the H1 phase. The mixture with 65.0 wt.% C12E6 exhibits L1, cubic (V1), H1 and Lα phases. The individual phase transitions between the H1, V1, Lα and L1, phases in sequence were clearly evident in the reduced density. The H1–V1 and V1–Lα phase transitions are of second order.

Solubilization Behaviour of Water in Hexaethylene Glycol Dodecyl Ether Reverse Micelles in Apolar Solvents

Using 1 H and 13 CNMR, near infrared, ESR and light scattering techniques, the solubilization behavior of water and the formation of reversed micelles by hexaethylene glycol dodecyl ether in cyclohexane and n-decane were examined as a function of the molar ratio water/surfactant at 25°C. The solubilization region of water was divided into three different states of water in cyclohexane, but in n-decane it was composed of two states. These different states were found to the correlated to the formation of reversed micelles. However, W/O microemulsions included the water droplets having similar property with bulk water could not be observed in any solvent systems.

Solubilization of alcohols in single and mixed surfactant aqueous solutions containing fluorocarbon surfactant

The solubilization of hydrocarbon and fluorocarbon alcohols in single and mixed aqueous solutions containing fluorocarbon surfactant has been studied. Surfactants used are lithium dodecyl sulfate (LiDS), lithium perfluorooctane sulfonate (LiFOS), lithium perfluorooctanoate (LiPFO), and hexaethyleneglycol dodecyl ether (6ED). In single surfactant systems, the partition coefficients of the alcohols between anionic micelles and water are greater for the surfactants which have the same kind of alkyl chain as the alcohols than for the surfactants having a different kind of alkyl chain to the alcohols. The standard free energies calculated from the partition coefficients indicate that the transfer of the alcohols occurs more favorably to the micelles consisting of the same kind of alkyl chain as the alcohols than of the different kind of alkyl chain. Also, the mixed surfactant systems LiDS-LiFOS, LiFOS-LiPFO and 6ED-LiFOS have been characterized by the regular solution parameter β and the alcohol partition coefficient. In the LiDS-LiFOS system with a positive β value, the partition coefficients of both hydrocarbon and fluorocarbon alcohols are greater than in single surfactant systems. In the LiFOS-LiPFO system exhibiting almost ideal mixing, the partition coefficients of both hydrocarbon and fluorocarbon alcohols change ideally, whereas the partition coefficients of the fluorocarbon alcohols are greater than those of the hydrocarbon alcohols. By contrast, in the 6ED-LiFOS system with negative β values, the partition coefficients of both alcohols are lower than in single surfactant systems.

Temperature dependence of the solubility areas for W/O microemulsions with nonionic/anionic surfactants

AbstractThe solubitity areas were determined at 30, 50 and 75 C for W/O microemulsions of water and decane stabilized by sodium dodecyl sulfate or hexaethylene glycol dodecyl ether in combination with pentanol. The results showed no pronounced changes when the ionic surfactant was partly replaced with the nonionic one and revealed an excellent temperature stability in the range 30–75 C for the W/O microemulsions.

Electric Birefringence studies on hexaethyleneglycol bodecyl ether

Transient electri birefringence has been used to reveal variable micelle morphology in the L 1 micellar dispersion region of hexaethyleneglycol dodecyl ether. The results are consistent with the occurrence of rod micelles in the solution adjacent to the hexagonal phase, and their gradual disappearance as the hexagonal phase melts.

Studies on Molecular Motion in Lyotropic Mesophases of Hexaethylene Glycol Dodecyl Ether–D2O System by 13C Nuclear Magnetic Resonance

Abstract The 13C spin-lattice relaxation time(T1) and the resonance line width corresponding to T2* were measured for each of the carbons in hexaethylene glycol dodecyl ether–water(D2O) system, which exists as two distinct lyotropic mesophases(neat and middle phase). The line width is very narrow in the isotropic state, such as in organic solvents and in a lower concentration aqueous solution, whereas in a mesophase and in a higher concentration aqueous solution, the line width of the alkyl chain was broadened. Here the line widths for glycol carbons were about an order of magnitude smaller than for an alkyl chain, demonstrating the difference of molecular motion. The chemical shifts of the alkyl chain in the middle phase were different from those in the isotropic state; this difference was clearly shown in the spectrum of the middle/isotropic coexistent phase. 13C-T1 was not sensitive enough to differentiate between the isotropic and the lyotropic phase at room temperature. It was found that T1 did not equal T2* for any of the methylene carbons, the difference being most marked for the terminal methyl carbon in the alkyl chain. The orientational order in the phases had an influence on the T2* values.