Effect of additives on the adsorption of sodium bis(2‐ethyl hexyl sulfosuccinate) at the air‐water interface studied by equilibrium and dynamic surface tension measurements

Abstract

Using equilibrium and dynamic surface tension measurements, we have studied the effect of the addition of poly(sodium 4-styrenesulfonate) (PSS), sodium chloride, and 1,4,7,10,13,16-hexaoxyacyclooctadecane (18-crown-6) on the surface properties of sodium bis(2-ethyl hexyl sulfosuccinate) (AOT). The addition of PSS or NaCl weakly increases the maximum packing of AOT, whereas the presence of 18-crown-6 slightly decreases the maximum surface coverage. The surfactant adsorption kinetics on the interface is a diffusion-controlled process. The two asymptotic solutions at long times and at short times to the classic Ward Tordai equation were used to fit dynamic results. At long times there is evidence of the existence of an electrostatic barrier at high surfactant concentration when using pure AOT and AOT mixed with PSS. In binary mixtures of AOT with sodium chloride or 18-crown-6, the electrostatic barrier is not observed over the surfactant concentration range studied.Paper no. S1292 in JSD 5, 397-402 (October 2002).KEY WORDS: Aerosol OT; 18-crown-6; dynamic surface tension; equilibrium surface tension; poly(sodium 4-styrensulfonate).Dynamic surface tension, γ(t), is an important property of surfactant solutions because several technological processes use surfactant solutions under nonequilibrium conditions. The dynamic surface tension also provides information on the kinetics of surfactant adsorption at the interface. It is well established that the transport of bulk soluble surfactant at the interface includes bulk diffusion and adsorption/desorption processes and that the controlling mechanism of this mass transfer can change as a function of bulk concentration (1-3), the kind of surfactant (1,4,5), and the counterion concentration (6,7). Industrially, surfactants are often mixed with polymers because mixtures provide more desirable properties than the pure surfactant (8-10). In foams and emulsions, polymers can affect the thermodynamic and dynamic properties of such mixtures. For instance, when soluble polymers are added to solutions they increase the bulk viscosity and can dramatically change the drainage of the thin liquid film. If the polymers are surface active, they can also influence the surface rheological properties and further decrease the rate of fluid flow out of the film (11,12). The correct use of these mixtures requires knowledge of their adsorption kinetics. Whereas the adsorption kinetics of pure surfactants has been extensively studied, there is not enough information about dynamic superficial properties of surfactant-polymer mixtures (13)(14)(15)(16)(17). This current work provides information on both equilibrium and dynamic properties of sodium bis(2-ethyl hexyl sulfosuccinate) (AOT) mixed with poly-(sodium 4-styrenesulfonate) (PSS) and mixed with the macrocyclic polyether 18-crown-6 (1,4,7,10,13,16-hexaoxyacyclooctadecane, C 12 H 24 O 6 ). It is well known that 18-crown-6 forms complexes (18) with several cations such as Na + ; therefore, the addition of this crown ether reduces the concentratio...

Effect of the addition of water-soluble polymers on the interfacial properties of aerosol OT vesicles

“…The cvc values found in this work are consistent with those obtained previously by electrical conductivity [18] or surface tension measurements [32]. These values show that the addition of PSS or PEG polymers or NaCl decreases the cvc of pure AOT vesicles.…”

Equilibrium and Dynamic Surface Properties of Sulfosuccinate Surfactants

“…Disodium laureth sulfosuccinates are synthesized from maleic acid anhydride and alcohol ethoxylates and they are not only widely used in low-irritation personal care products [5] but also proving their utilities in textile, polymer, paints, leather and agriculture industries [5,6]. Many reports [8][9][10][11] of sulfosuccinate focused on the colloidal properties, such as critical micelle concentration (CMC), foaming, wetting and other properties, whereas, the adsorption kinetics of sulfosuccinate surfactants are discussed only in a few reports [12,13].…”