Volume 51, Issue 2

In this study, we have investigated the development of liquid laundry detergent formulations over the past 10 years with regard to performance and sustainability profiles. We found that between 2001 and 2011, wash performance has significantly increased while at the same time the surfactant level was substantially reduced, leading to lower Global Warming Potential and improvements in all other relevant lifecycle indicators. One driver is the partial replacement of surfactants with other, more effective ingredients like enzymes that allow for additional performance dimensions and new consumer-relevant benefits. Future surfactant systems that help increase and support the stability and functionality of enzymes will further boost performance at low temperature, improve storage stability and enable more concentrated formulations at competitive costs.

Cleaning power of different surfactants was investigated using a model detergent system consisting of a PET film and stearic acid. Surfactants used were alcohol ethoxylates (AE, C12) and methyl ester ethoxylates (MEE, C12) with different ethylene oxide (EO) chain lengths. For comparison with these nonionic surfactants, anionic surfactant, sodium alkyl sulfate (AS, C12), was chosen. After depositing stearic acid, the PET film was cleaned in aqueous surfactant solutions by applying stirring as a mechanical action for soil removal. The amounts of stearic acid deposited on the PET film before and after the cleaning were obtained by binary processing of microscopic images of the PET film surface, from which the removal efficiency was calculated. The surface tension γ and the contact angle on the PET film θ of the surfactant solution were measured by the pendant drop and the sessile drop method, respectively. For the nonionic surfactants, critical micelle concentration, cmc, and γ and θ above cmc decreased with decreasing EO chain length. The removal efficiency of stearic acid increased with increasing surfactant concentration and further increase in the removal above cmc was observed in the cases of AE and MEE with EO chain length of 10. The removal efficiencies obtained in all systems had good relation with both γ and θ, indicating that the penetration of the surfactant solution between stearic acid and the PET film in the contact zone was a dominant factor in the soil removal in the present system.

The aim of this work is to propose a contribution to obtain an improvement in the redeposition of solid impurities on cotton fabric during washing with ecological surfactants and also the enhancement of their smoothness. For that purpose, sodium bentonite was added to the detergent formulations to produce a smoothing effect while washing, to obtain what is known as “softergent”. Thus, smoothing with this product, the necessity of adding softener in the last rinse during washing is eliminated, with the savings of softeners and time and more ecological waste water. This was possible given the excellent compatibility of the bentonite with all the components of the detergent. As a water-soluble inorganic salt, bentonite is environmentally friendly. The surfactants used in the detergent formulations were the anionic sodium dodecylbenzene sulfonate (SDBS) and the two non-ionic surfactants, APG and AE with 7 m. EO, which were used separately and in mixtures of different proportions of anionic and non-ionic surfactants. The sodium bentonite (composed mainly of silicates and aluminates) was used with two types of particle size, without surface treatment and with and without ammoniumsilicone softener treatment to show the effect on their behaviour. The redeposition behaviour on the cotton fabric and the smoothness produced after washing with bentonite microparticles in the detergent formulation, depending on use of the surfactants alone or in the different proportions of anionic : non-ionic surfactants were measured. The smoothness of cotton fabrics produced by the bentonite microparticles after washing was evaluated by hand. A relationship between handle and inorganic ash contents was established. Also, the electrical double layer of the bentonites was measured in the presence of the surfactants tested.

The primary aim of this work is to attain improvement of the softness of cotton fabric during the washing process with ecological surfactants. To attain that improvement, sodium bentonite was added to the detergent formulations to produce a softening effect during washing and obtain the so called “soft detergent” effect. Sodium bentonite (a mineral composed mainly of hydrated aluminium silicates) was mixed with the surfactants used in ecological detergents. This product was used with a suitable particle size that, given its large specific surface area, facilitated its deposition on the cotton fabric, producing the desired effect of increasing the softness of the washed fabric. The surfactants used were an anionic surfactant, namely LAS, and two non-ionic surfactants, namely APG and AE, used separately and as mixtures, without co-formulants, to demonstrate their detersive power in one wash and repeated washes, depending on the nature of the surfactants and on their separate mixtures and mixtures in different proportions of anionic and non-ionic surfactants in combination in all cases with a constant concentration of sodium bentonite with two particle sizes. Evaluation was performed of the subjective softness (to the touch) of pairs of samples by several observers and also of changes in whiteness after deposition of the bentonite during washing.

Alkyl polyglucosides (APGs) are a perfect amphiphilic structure, with excellent surface activity and solubility feature. The aim of this study is to develop a simple system, with a relatively low emulsifier content, composed of materials mainly naturally based and with no additional fatty alcohol. Hydroxystearyl alcohol and Hydroxystearyl glucoside, prepared with Jojoba and Hazelnut oil, medium chain triglycerides with or without Xylitylglucoside and Anhydroxylitol and Xylitol, have been investigated by using microscopy, rheology, thermal analysis, pH and conductimetry. Cyclic stress and in vivo skin irritation tests were also conducted. The investigated natural APG emulsifier has a capacity to form simple and stable emulsions of desirable rheological profile with improved hydration potential and to renew damaged skin, thus it can be safely applied as stabilizer in cosmetic and prospective pharmaceutical cream-bases.

The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) and anionic micelles of sodium dodecyl sulphate (SDS) on the kinetics of oxidation of cyclopentanone by N -bromophthalimide (NBP) was studied iodometrically at 308 K. In addition to the kinetic experiments, conductivity measurements have also been done to obtain critical micelle concentration and other thermodynamic properties. The kinetic observations indicate fractional order and first order dependence with respect to [cyclopentanone] and [NBP] respectively. Cationic surfactant (CTAB) strongly catalyses the oxidation of Cyclopentanone in aqueous acetic acid medium. Typical k obs and [CTAB] profile were observed i. e. with the progressive increase in [CTAB], the reaction rate increased and at higher concentration of CTAB, constancy in k obs was observed. Anionic surfactant (sodium dodecylsulphate, SDS), mercuric acetate and phthalimide did not influence the reaction rate. The presence of inorganic salts (KCl, KBr) exhibits a severe hike in the reaction rate. The various activation parameters in the presence of CTAB have been also evaluated. A suitable mechanism consistent with the experimental findings has been proposed.

In this paper, we are reporting the influence of cationic CTAB surfactant on the interaction of chromium(III) complex of glycylphenylalanine [Cr(III)-Gly-Phe] 2+ with ninhydrin under varying experimental conditions. The reaction follows irreversible first-order reaction kinetics with respect to [complex] and fractional-order with respect to [ninhydrin]. With progressive increase in [CTAB], the rate constant ( k Ψ ) for condensation of ninhydrin into [Cr(III)-Gly-Phe] 2+ complex increased, reached a maximum value, and then decreased. The results are best accounted for by the distribution of substrate into micellar and aqueous pseudo-phases as well as combination of substrate molecules with surfactant molecule. On the basis of above results, template mechanism has been discussed.

The present study investigates the synergistic effect of the anionic surfactant sodium dodecyl sulfate micelles (SDS) on the solvent extraction of copper(II) from saline sulfate medium by some ortho-hydroxy Schiff base extracting agents (HL) in chloroform at (25 ± 2)°C. The Schiff base extractants used are N-salicylideneaniline (HSA), N-(2-hydroxy-1-naphthalidene)aniline (HNA) and N-(2-hydroxy-1-naphthalidene)naphthylamine (HNN). In the absence of SDS, the estimated extraction constants of the three ligands revealed that the extraction efficiency increased in the order HNN < HNA < HSA. The extraction of Cu(II) was remarkably enhanced with HL upon the addition of the SDS surfactant. It was found that SDS did not intervene in the coordination sphere of the Cu(II). The calculated synergistic constant fell in the order HNN > HNA > HSA. A synergistic extraction mechanism of copper(II) with ortho-hydroxy Schiff bases in the presence of the surfactant has been proposed.

Gemini surfactant, N,N′-bis(dimethyl ethyl dodecane)ethyl ether dibromide was synthesized and symbolized as II-12-EO 2 . The surface chemical properties and micelle behaviors of II-12-EO 2 with poly (ethylene oxide) (PEO) lauryl ether (C 12 E 6 ) and sodium dodecyl sulfate (SDS) were investigated in 0.1 mol · L −1 sodium bromide aqueous solution at 313 K using surface tension measurements and steady-state fluorescence spectroscopy. The critical micelle concentration (cmc) of II-12-EO 2 is 1.99 × 10 −4  mol · L −1 and the aggregation number is 23. The cmc values of the two binary systems with different molar fractions are all lower than those of pure constituent surfactants, and the aggregation numbers of the binary systems are all larger than that of II-12-EO 2 . The interaction parameters β of the two binary systems were calculated, and the negative values of β indicate the existence of synergism in surface tension reduction efficiency, mixed micelle formation and surface tension reduction effectiveness.