Conventional Nonionic Surfactants Research Articles

Study on the effect of structure of polydimethylsiloxane grafted with polyethyleneoxide on surface activities

Twelve kinds of polydimethylsiloxane grafted with polyethyleneoxide (PDMS-g-PEO) were synthesized by two-step reactions: the preparation of silicone backbone containing methyl-hydrogen siloxane units and the following hydrosilylation reactions with PEO containing allyl groups. When the effects of structure of PDMS-g-PEO on the surface properties were investigated by comparing the each effect caused by EO content, EO chain length or the size of hydrophobe, the size of hydrophobe was found to be a critical factor for deciding surface tension rather than the content of EO. Significant decrease in the contact angle of the aqueous solution was observed when EO content of PDMS-g-PEO or the surfactant concentration increased. On the other hand, the viscosity of the surfactant solution at constant concentration slightly increased as EO content increased, but the difference was not significant. Dynamic surface tension measurement showed a decrease in the surface tension of the aqueous surfactant solution with an increase in the surfactant concentration. In addition, much longer times were required to reach an equilibrium compared with conventional nonionic or ionic surfactants due to the lower mobility of PDMS-g-PEO with high molecular weight.

Equilibrium partition of polycyclic aromatic hydrocarbons in cloud point extraction with a silicone surfactant

In the cloud point extraction (CPE) process with PEG/PPG-18/18 dimethicone, the flexible chain structure of the silicone surfactant efficiently decreased the water content remaining in the surfactant-rich phase, compared with conventional nonionic surfactants, represented by Triton X-114. Meanwhile, the phase volume ratio of surfactant-rich phase to aqueous phase obtained in the silicone surfactant CPE system was found to be maintained at a low value with increasing surfactant concentration; whereas a rapid increase tendency was commonly observed in that of other nonionic surfactants. Based on these advantages, the equilibrium partition of three polycyclic aromatic hydrocarbons (PAHs), anthracene, phenanthrene and pyrene, was studied in the CPE process with PEG/PPG-18/18 dimethicone. Equilibrium parameters, including preconcentration factor, distribution coefficient and recovery, were determined, and the performance was compared with that of another related CPE research, where Tergitol 15-S-7 was used. Due to the low surfactant-rich phase volume, higher concentrations of the three PAHs in the surfactant-rich phase, and the resulting higher preconcentration factors and distribution coefficients were able to be achieved at the same time. Moreover, the great performance was able to be maintained even at a high surfactant concentration or PAHs initial concentration.

Mixed micellization of an anionic gemini surfactant (GA) with conventional polyethoxylated nonionic surfactants in brine solution at pH 5 and 298 K

The micellization behavior of an anionic gemini surfactant, GA with nonionic surfactants C12E8 and C12E5 in presence of 0.1 M NaCl at 298 K temperature, has been studied tensiometrically in pure and mixed states, and the related physicochemical parameters (cmc, γ cmc, pC 20, Γ max, and A min) have been evaluated. Tensiometric profile (γ vs log [surfactant]), for conventional surfactants, generally consists of a single point of intersection; a gradually decreasing line (normally linear, or with slight curvature) ultimately saturates in γ at a particular [surfactant], corresponding to complete monolayer saturation. The gemini, in this report, led to two unequivocal breaks in the tensiometric isotherm. An attempt to the interpretation of the two breaks from molecular point of view is provided, depending solely on the chemical structure of the surfactant. The gemini, even in mixed state with the conventional nonionic surfactants C12E5 and C12E8, manifested the dual breaks; of course, the dominance of the feature decreases with increasing mole fraction of the nonionics in the mixture. Theories of Clint, Rosen, Rubingh, Motomura, Georgiev, Maeda, and Nagarajan have been used to determine the interaction between surfactants at the interface and micellar state of aggregation, the composition of the aggregates, the theoretical cmc in pure and mixed states, and the structural parameters according to Tanford and Israelachvili. Several thermodynamic parameters have also been predicted from those theories.

Persistence Length of Wormlike Micelles Composed of Ionic Surfactants: Self-Consistent-Field Predictions

The persistence length of a wormlike micelle composed of ionic surfactants C(n)E(m)X(k) in an aqueous solvent is predicted by means of the self-consistent-field theory where C(n)E(m) is the conventional nonionic surfactant and X(k) is an additional sequence of k weakly charged (pH-dependent) segments. By considering a toroidal micelle at infinitesimal curvature, we evaluate the bending modulus of the wormlike micelle that corresponds to the total persistence length, consisting of an elastic/intrinsic and an electrostatic contribution. The total persistence length increases with pH and decreases with increasing background salt concentration. We estimate that the electrostatic persistence length l(p,e)(0) scales with respect to the Debye length kappa(-1) as l(p,e)(0) approximately kappa(-p) where p approximately 1.98 for wormlike micelles consisting of C(20)E(10)X(1) surfactants and p approximately 1.54 for wormlike micelles consisting of C(20)E(10)X(2) surfactants. The total persistence length l(p,t)(0) is a weak function of the head group length m but scales with the tail length n as l(p,t)(0) approximately n(x) where x approximately 2-2.6, depending on the corresponding head group length. Interestingly, l(p,t)(0) varies nonmonotonically with the number of charged groups k due to the opposing trends in the electrostatic and elastic bending rigidities upon variation of k.

Mixed Micellization of Alkylbenzene Sulfonate Gemini Surfactant Ia and Nonionic Surfactant C 10E 6 in Aqueous Solution

The interaction between the alkylbenzene sulfonate Gemini surfactant Ia and the conventional nonionic surfactant C 10E 6 was investigated. The critical micelle concentrations of different mixtures were measured by surface tension measurement in aqueous solution at different temperatures. The results suggested that the critical micelle concentration of different mixtures at any mole ratio was lower than that of either pure Ia or C 10E 6 surfactant, indicating synergetic behavior. The cmc values for pure Ia, C 10E 6 surfactant, and their different mixtures at any mole ratio increased with increasing temperature. And the interaction parameter β values for the mixed micelles were negative, showing attractive interaction between these surfactant molecules. The micelle aggregation number ( N) was measured using a steady state fluorescence quenching method. The N values of the mixed surfactant system were larger than those of pure Ia but lower than those of pure C 10E 6 at all mole ratios. The micropolarity of micelles becomes small gradually with the increase of the mole ratio of the Gemini surfactant Ia.

Improving Water Sensitivity in Acrylic Films Using Surfmers

The water sensitivity of films obtained from high solids content acrylic latexes was investigated, with special focus on the role of the surfactant used in the synthesis step. The performance of films obtained from latexes stabilized by nonionic surfmers was compared to that of the acrylic latexes stabilized with conventional nonionic and anionic surfactants. It was seen that the latexes stabilized with reactive surfactants exhibited a remarkably better resistance to both water permeability and water vapor permeability and therefore enlarged the durability of the films. Atomic force microscopy images suggested that the defects created by surfactant migration in the latexes stabilized with conventional surfactants promoted the permeation of water by capillarity.

Surface and micellar properties of new nonionic gemini aldonamide-type surfactants

A new group of gemini aldonamide-type surfactants— N, N′-bisalkyl- N, N′-bis[(3-gluconylamide)propyl]ethylenediamines, N, N′-bisdodecyl- N, N′-bis[(3-glucoheptonylamide)propyl]ethylenediamine, and N, N′-bisalkyl- N, N′-bis[(3-lactobionylamide)propyl]ethylenediamines, (alkyl: n-C 8H 17, n-C 12H 25), were synthesized and characterized. The surface properties, such as surface excess concentration, Γ cmc, surface area demand per molecule, A min, efficiency in surface tension reduction, p C 20, the effectiveness of surface tension reduction, γ cmc, critical micelle concentration, cmc, and a measure of the tendency of the surfactant to adsorb at the aqueous/air interface relative to its tendency to form micelles in the bulk surfactant solution, cmc/ C 20, and standard free energy of micellization, Δ G mic 0, have been obtained by means of surface tension measurements. The standard fluorescence shift technique using PRODAN as a probe provide confirmation of the cmc values by an alternative method. Additionally, the micellar properties for the concentration near above the cmc have been characterized by the aggregation number, N agg. The presence of the dimeric segments with the aldonamide hydrophilic units in the surfactant molecule is found to be the source of their unusual physicochemical behavior. They are very efficient at adsorbing at the free surface and at forming micelles in water. Their critical micelle concentration values are remarkably low. They reveal remarkably low A min values in relation to conventional nonionic surfactants, which is unexpected from the molecular dimensions for the molecule but which is possible if one assumes some type of multilayer structure or a coherent interfacial film.

Studies of mixed surfactant solutions of cationic dimeric (gemini) surfactant with nonionic surfactant C 12E 6 in aqueous medium

The interaction between the alkanediyl- α, ω-type cationic gemini surfactant, [(C 16H 33N +(CH 3) 2(CH 2) 4N +(CH 3) 2C 16H 33)2Br −], 16–4–16 and the conventional nonionic surfactant [CH 3(CH 2) 10CH 2(OCH 2CH 2) 6OH], C 12E 6 in aqueous medium has been investigated. The critical micelle concentrations of different mixtures have been measured by surface tension using a du Nouy tensiometer in aqueous solution at different temperatures (303, 308, and 313 K). Maximum surface excess ( Γ max) and minimum area per molecule ( A min) were evaluated from a surface tension vs log 10 C ( C is concentration) plot. The cmc value of the mixture was used to compute β m , the interaction parameter. The β σ , the interaction parameter at the monolayer air–water interface, was also calculated. We observed synergism in 16–4–16/C 12E 6 system at all concentration ratios. The micelle aggregation number ( N agg) has been measured using a steady state fluorescence quenching method at a total surfactant concentration ∼2 mM at 25 °C. The micropolarity and the binding constant ( K sv) of mixed systems were determined from the ratio of intensity of peaks ( I 1/ I 3) of the pyrene fluorescence emission spectrum. The micellar interiors were found to be reasonably polar. We also found, using Maeda's concept, that the chain–chain interactions are very important in this system.

Adsorption of Acetylenic Diol-Based Nonionic Surfactants on Lampblack and Phthalocyanine Blue Pigment

The adsorption of acetylenic diol based surfactants on lampblack and phthalocyanine blue has been studied to determine the mechanisms of surfactant adsorption and the orientation of these molecules at hydrophobic surfaces. The TMDD series of reagents, commonly known as acetylenic diol-based surfactants, are derivatives of 2,4,7,9-tetramethyl-5-decyne-4,7-diol. While studies of conventional nonionic surfactants have included alkyl ethoxylates and ethoxylated alkyl phenol surfactants, limited information is available for acetylenic diol-based surfactants. The effect of the degree of ethoxylation of these surfactants was determined. Although the Langmuir model could be used to fit adsorption data in many cases, further analysis of the data showed that the free-energy per molecule was a function of adsorption density. The change in free energy with adsorption density could be interpreted by considering a change in the orientation of the adsorbed molecules. Acetylenic diol-based surfactants were found to have an area per molecule of two to three times that of similarly ethoxylated alkyl phenols. The area per molecule was found to increase linearly with increased ethoxylation within each family of surfactants.

Wetting and adsorption of acetylenic diol based nonionic surfactants on heterogeneous surfaces

Abstract The wetting and adsorption of acetylenic diol based surfactants on lampblack and phthalocyanine blue was studied to determine the mechanisms of wetting of heterogeneous surfaces. The TMDD series of reagents, commonly known as acetylenic diol based surfactants, are derivatives of 2,4,7,9-tetramethyl-5-decyne-4,7-diol. While studies of conventional nonionic surfactants have included alkyl ethoxylates and ethoxylated alkyl phenol surfactants, limited information is available for acetylenic diol based surfactants. The effect of the degree of ethoxylation of these surfactants on adsorption and wetting of pigments was studied. Although the Langmuir model could be used to fit adsorption data in many cases, further analysis of the data showed that the free energy of adsorption was a function of adsorption density. The change in free energy with adsorption density could be interpreted by considering a change in the orientation of the adsorbed molecules. At monolayer coverage, acetylenic diol based surfactants were found to have an area per molecule of 2–3 times that of similarly ethoxylated alkyl phenols. The area per molecule was found to increase linearly with increased ethoxylation within each family of surfactants. The surface tension of these surfactants at the liquid/air interface was also investigated to delineate the effects of ethoxylation on the adsorption mechanisms.

Phase Behavior of a Mixture of Poly(oxyethylene)−Poly(dimethylsiloxane) Copolymer and Nonionic Surfactant in Water

The A−B-type silicone copolymer, Me3SiO−(Me2SiO)23−Me2SiCH2CH2CH2−O−(CH2CH2O)51.6H (Si25C3EO51.6), forms only lamellar liquid crystal (Lα) in water over a whole range of concentrations. Rich phase behavior was observed upon addition of conventional nonionic surfactant, C12EO5, whose molecular weight is ∼1/10 of Si25C3EO51.6. For both amphiphiles, f, the volume fraction of hydrophilic part in amphiphile, is the same, and f = 0.5. C12EO5 alone forms aqueous micellar solution (Wm), normal hexagonal (H1), bicontinuous cubic (V1), lamellar (Lα), and reverse micellar solution (Om) phases in water with increasing surfactant concentration. On the other hand, Wm, discontinuous micellar cubic (I1), Lα, reverse bicontinuous cubic (V2), and reverse hexagonal (H2) phases are successively formed in water at a 70/30 weight ratio of Si25C3EO51.6/C12EO5. A reduction in the effective cross-sectional area per amphiphile at hydrophobic surface (aS) takes place upon addition of C12EO5 in the mixed system. A small amphiphile, ...

Micellization of Nonionic Surfactant Dimers and of the Corresponding Surfactant Monomers in Aqueous Solution

Two nonionic surfactant dimers (gemini surfactants) of the dimethylene 1,2-bis(N-polyethyleneglycol dodecylamide) type and the corresponding surfactant monomers of the N-methyl, N-polyethyleneglycol dodecylamide type have been synthesized with an increasing number of ethyleneglycol (EG) units in the head group. Their micellization behavior in aqueous solution has been investigated. The cloud temperature, cmc, and micelle aggregation number have been measured using turbidity, surface tension, pyrene fluorescence probing, and time-resolved fluorescence quenching. The results permitted the first direct comparison between the micellar properties of nonionic surfactant monomers and dimers having polar head groups of the polyethyleneglycol type. The nonionic surfactant dimers are more efficient and effective at reducing the surface tension of water and are characterized by a lower cloud temperature, a lower cmc (by about one order of magnitude), and larger micelle aggregation numbers than the corresponding surfactant monomers. Overall the effect of the number of EG units on the micellar properties of the synthesized surfactants has been found to be very similar to that reported for conventional nonionic surfactants of the polyethyleneglycol monododecylether type.

Comparing the Surface Chemical Properties and the Effect of Salts on the Cloud Point of a Conventional Nonionic Surfactant, Octoxynol 9 (Triton X-100), and of Its Oligomer, Tyloxapol (Triton WR-1339)

The surface-chemical properties, critical micelle concentrations (CMC), and effect of salts on the cloud points (CP) of octoxynol 9 (Triton X-100) and tyloxapol (Triton WR-1339) were compared. The latter nonionic surfactant is essentially a heptamer of the former. Even though the molecular weight of tyloxapol is 7 times larger than that of octoxynol 9, its area per molecule adsorbed at the air–water interface is only twice as large. This suggests an unusual orientation for molecules of tyloxapol at the surface and is in keeping with a plateau that is less horizontal and has a somewhat higher surface tension than the plateaus of most nonionic surfactants. The CMC of octoxynol 9 was 4.4 times larger than that of tyloxapol. Unexpectedly, the CP of dilute aqueous tyloxapol solutions was 28°Chigherthan that of octoxynol 9 solutions. The salting-out ions Na+, Cl−and SO2−4lowered the CP of tyloxapol 29% more than that of octoxynol 9. However, because the blank tyloxapol solution started out with a higher CP value, its CPs in the presence of salts were higher than those of octoxynol 9. Pb2+and Mg2+cations salted both surfactants in, raising their CP, Pb2+more extensively than Mg2+.

Influence of Adjuvants and Formulation on Barnyardgrass (Echinochloa crus-galli) Control with Propanil in Rice (Oryza sativa)

Experiments were conducted to compare barnyardgrass control and rice injury and yield with emulsifiable concentrate and dry flowable formulations of propanil as single or repeat applications with crop oil concentrate, methylated seed oil, a blend of organosilicone surfactant and methylated seed oil or conventional nonionic surfactant, and organosilicone surfactant. Two applications of propanil were more effective in controlling barnyardgrass than a single application. The emulsifiable concentrate formulation of propanil controlled barnyardgrass more effectively than the dry flowable formulation in some but not all experiments. Differences in barnyardgrass control with propanil as influenced by adjuvants were minor and inconsistent. The most consistent barnyardgrass control and the highest rice yields were obtained with repeat applications of the emulsifiable concentrate formulation of propanil.

Influence of Adjuvants on Efficacy of Clethodim

Field experiments evaluated barnyardgrass, broadleaf signalgrass, and rhizomatous johnsongrass control with clethodim applied with Agri-Dex® crop oil concentrate at 1.0% v/v, the adjuvant Dash® at 1.0% v/v, the methylated seed oil Sun-It II® at 1.0% v/v, a blend of silicone surfactant plus methylated seed oil (Dyne-Amic® at 0.5% v/v) or nonionic surfactant (Kinetic® HV at 0.125% v/v), two silicone surfactants (Sylgard® 309 and Silwet L-77® surfactant) at 0.125% v/v, two other conventional nonionic surfactants (Latron AG-98™ and Induce®) at 0.25% v/v, and the acidified soya phospholipid LI-700®. When compared with the conventional nonionic or silicone-based surfactants and LI-700, clethodim at 70 g ai/ha controlled barnyardgrass more effectively when applied with Dash or Sun-It II. Broadleaf signalgrass and rhizomatous johnsongrass were controlled more effectively when clethodim was applied with Agri-Dex, Dash, Sun-It II, or Dyne-Amic. Clethodim at 70 g/ha applied with Dash or Sun-It II controlled grasses equally or greater than clethodim at 140 g/ha.

Silicone surfactants in aqueous solution

The surface and colloid-chemical behaviour of some non-ionic silicone surfactants in water was studied by surface tension, viscosity, dye solubilization, cloud point and light scattering (static and dynamic) measurements over a temperature range of 20-60°C While surface tension data reveal that silicone surfactants possess high surface activity, the viscosity results showed their micelles were spherical. Light scattering studies yielded the micelle aggregation number and hydrodynamic radius which showed a gradual increase with increasing temperature. These results also indicated a low polydispersity in hydrodynamic micelle size. The micellar and solubilizing behaviour of surfactants was dependent on the magnitude of hydrophilic (polyethylene oxide) and hydrophobic (polydimethyl siloxane and/or polypropylene oxide) moieties of the surfactants. The cloud points of the silicone surfactant solutions changed in the presence of electrolytes (KI, KCNS, KBr, KCl, KF) and showed a behaviour similar to the conventional non-ionic surfactants.

Volumetric Behavior of ((Dodecyloxy)methyl)-18-Crown-6 in Water: Micellar Interactions and Phase Separation

The densities of aqueous solutions of ((dodecyloxy)methyl)-18-crown-6 (C12-OM-crown) were measured at various temperatures (5−45 °C). The partial molar volume of the micelles at infinite dilution (Vm°) in water increased linearly with the temperature below the cloud point (tc = 30.5 °C) of aqueous C12-OM-crown solutions from 443.7 cm3/mol at 5 °C to 452.9 cm3/mol at 25 °C. C12-OM-crown micelles seemed to be more bulky than micelles of conventional nonionic surfactants having an oligo(oxyethylene) chain, because of a cyclization effect of the chain. Vm° increased upon the addition of KCl. In 0.5 mol/dm3 KCl systems, the Vm°−temperature (T) plot comprised two linear sections with a break point at around 25 °C, one of which at over 25 °C nearly agreed with the extrapolated line of the Vm°−T relation for a no-salt system. The agreement seems to imply a certain compensation effect on the molar volume of partially chelated mixed micelles, since the difference (4.1 cm3/mol) in Vm° at 5 °C between water and 0.5 m...

New cleavable surfactants derived from glucono‐1,5‐lactone

AbstractNew amido nonionic cleavable surfactants were synthesized in good yields by the acetalization of glucono‐1,5‐lactone with octanal, 2‐octanone or 2‐undecanone, followed by amidation with monoethanolamine, diethanolamine or morpholine. These compounds possessed good water solubilities. The compounds derived from 2‐octanone showed higher critical micelle concentrations than the compounds from octanal. For the same hydrophobic chain, both the micelle‐forming property and the ability to lower surface tension increased with the change in the terminal amide group in the order diethanolamide<morpholide<monoethanolamide. Interestingly, in spite of their relatively short hydrophobic chains, these compounds showed greater ability to lower surface tension than conventional nonionic surfactants, such as alcohol ethoxylates. Furthermore, their acid‐decomposition properties were determined. Their decomposition rates were also compared with that of the corresponding carboxylate type of compound derived from glucono‐1,5‐lactone.

Effects of the ethylene oxide distribution on nonionic surfactant properties

AbstractDetergent‐range primary alcohols are readily converted into nonionic surfactants by reaction with ethylene oxide. Optimum performance properties for these surfactants generally are attained by varying the number of moles of ethylene oxide reacted with each mole of alcohol or by altering the structure of the primary alcohol. However, variations in the ethoxylate‐adduct distribution also affect surfactant properties in such a way that products with relatively narrow distributions possess features which are highly desirable in many household and industrial applications. For a given cloud point narrow‐range ethoxylates have lower molecular weights and therefore lower pour points than broad‐range surfactants. Because narrow‐range ethoxylates contain less unreacted alcohol and other water‐insoluble species, they are capable of forming aqueous solutions with much lower cloud points than their broad‐range counterparts. Aqueous solutions of narrow‐range products have lower viscosities, exhibit lower gel temperatures and remain fluid over a wider concentration range than solutions of broad‐range surfactans. While the foams obtained with narrow‐range surfactants in the Ross‐Miles test are higher initially, they are less stable than those produced by conventional nonionic surfactants. Draves wetting data show that narrow‐range products wet cotton substrates more efficiently than normal‐distribution materials. Narrow‐range ethoxylates exhibit higher aqueous surface tension and higher polyester adhesion tension values than their broad‐range counterparts. In addition, narrow‐range surfactants reduce the interfacial tension against paraffin oil more efficiently and more effectively than broad‐range products. These results, along with laboratory detergency data, suggest that the use of narrow‐range ethoxylates may lead to cleaning systems with improved performance and/or physical properties.

Preparation and Properties of Organosilicon Surfactants

Abstract Surface-active polyethenoxy silicic esters were prepared by the reaction of tetraethyl silicate with various polyethenoxy higher alkyl ethers by the use of tetrabutyl titanate as a catalyst. Their properties as surfactant were compared with those of conventional nonionic surfactants. These compounds are soluble in many kinds of organic solvents, and have good dispersing power on such inorganic pigments as titanium oxide in organic media. The dispersing characteristics of these compounds in the inorganic pigments were tested in benzene, carbon tetrachloride, and monochlorobenzene by measuring the sedimentation volume. It was found that the compounds containing a chain of more than six ethenoxy groups were soluble in water. The surface tension of these water-soluble polyethenoxy silicic esters were determined in various concentration regions. In this paper, the preparation and properties of these compounds will be described.