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Novel surfactants which are nowadays available for incorporation into various formulations of personal care and cosmetic products are numerous, implying a permanent need for their classification. This overview provides essential information relating to synthesis, basic physicochemical characteristics, application and other relevant data on surfactants currently used in cosmetic products. In the second part of the paper an outline of acidic active substances with significant application in cosmetic products is given, as well as the problems that arise during preparation/manufacture of the containing formulations, accompanied with the review of scientific publications and other available reliable data dealing with the incorporation of these actives in the cosmetic formulations stabilized with novel (mainly natural) surfactants.

The aim of the study was to determine the relation between the biological activity of two homologous series of cationic gemini surfactants, which are quaternary ammonium salts, and their structure. The measure of the biological activity of the compounds was assumed to be the effects they exert on the membrane of erythrocytes, treated as a simple model of the biological membrane. In particular, it was determined the effects of the compounds on hemolysis and the osmotic resistance of erythrocytes and the fluidity of erythrocyte membrane, and the packing arrangement of the polar heads of membrane lipids. The results have shown that surfactants affect the osmotic resistance of erythrocytes to various degrees, and at sufficiently high concentrations operate destructively on their membrane, eventually causing hemolysis, modify the fluidity of erythrocyte membrane and affect the arrangement of polar heads of membrane lipids. Additionally, the results showed that that activity depends on a surfactant's chemical structure, in particular, on the length of its alkyl chain and structure of the polar head group that determines the spacing between the chains. In both used new series the compounds containing 10, 12 and 14 carbon atoms in a chain possess a high biological activity. In addition, the surfactants with larger spaces between the chains are more active than those with smaller spacing. The investigations have revealed a high activity of compounds with longer chains and bigger polar heads. The results of the study may find application when designing a molecular structure and synthesizing new compounds of specific, desired activity.

1-Hydroxyethylidene-1,1-diphosphonic acid is a widely used CaCO 3 scale inhibitor. To probe its inhibition mechanisms, the effect of 1-Hydroxyethylidene-1,1-diphosphonic acid on surface charge and crystalline form of CaCO 3 scale was investigated. The results show that CaCO 3 originated from the equimolar mixture of Ca 2+ and CO 3 2 − is negatively charged and 1-Hydroxyethylidene-1,1-diphosphonic acid has no obvious effect on the zeta potential of CaCO 3 . Analysis of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction indicated that the crystalline form of CaCO 3 was altered in presence of 1-Hydroxyethylidene-1,1-diphosphonic acid. With the increase of the scale inhibition efficiency, more vaterite appeared in the particle. So a conclusion was drawn that the formation and transformation of the metaphase was inhibited by 1-hydroxyethylidene-1,1-diphosphonic acid, then the whole process of CaCO 3 precipitating was slowed greatly.

In this study, a novel environmentally friendly copolymer acrylic acid-itaconic acid-allylpolyethoxy maleic carboxylate was synthesized and used for inhibiting the calcium sulfate dehydrate (gypsum) scale. The properties of the synthesized copolymer were characterized by Fourier-transform infrared, nuclear magnetic resonance spectroscopy and thermal gravity analysis. Also, the structure and morphology changes of scale crystals were studied by scanning electronic microscopy, transmission electron microscopy and X-ray powder diffraction analysis. The copolymer inhibition ability was evaluated by means of static scale inhibition experiments. Results show that the copolymer was effective in inhibiting the scales by changing the size and morphology of the crystals. The maximum inhibition efficiency was 99.8% at a concentration of 2 mg · L – 1 , far more efficient than most commercial inhibitors.

The spontaneous formation of vesicles in aqueous catanionic mixtures, composed of six double-chain cationic surfactants 2,3-bis (alkyl carbamoyloxy)-N, N-dimethyl-N-(2-hydroxy alkyl) propyl chloride (C n PAC, n = 12, 14) and the three conventional anionic surfactants sodium dodecylbenzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SAS), was investigated. The aggregation behavior of a catanionic system is proved by visual observation, electrical conductivity, dynamic light scattering (DLS), zeta (ζ) potential, and transmission electronic microscopy (TEM). By variation of the mixing ratios of cationic and anionic surfactants, we find that the formed vesicles are stable, and the complex system with hydrophobic C 14 tail shows larger turbidity than that of hydrophobic C 12 tail. The positive and negative electrostatic interactions are regarded as the main driving forces for vesicles formation.

The micellization process of model cationic surfactants, alkyltrimethylammonium bromides with different alkyl chain length: dodecyl-(C 12 TAB), tetradecyl-(C 14 TAB) and hexadecyl- (C 16 TAB) has been investigated by the conductivity measurements over the temperature range 298.2 K–313.2 K. Understanding micelle formation requires its complete thermodynamic parameters, which were estimated by applying the proposed alternative derivation of pseudo-phase model. The critical micelle concentration (CMC), standard free Gibbs energy (Δ mic G 0 ), enthalpy (Δ mic H 0 ) and entropy (Δ mic S 0 ) of micellization were analysed as a function of the increase in alkyl chain and temperature. At lower temperatures, the micellization in each case was found to be entropy-driven due to the increase in bulk water entropy. London or dispersion interactions are responsible for the cohesion between the apolar chains in the micelles and increase as the length of chains increases. Δ mic H 0 reflects the contribution of London interactions, electrostatic repulsion between head groups and removing the alkyl chains from water (dehydration of CH 2 and CH 3 groups). As the temperature is increased, less energy is required for dehydration and hence the enthalpy of micellization became more exothermic and its effect more significant. The enthalpy-entropy compensation phenomenon was observed for all studied surfactants.

The surface tension of the mixed system of linear alkylated diphenylmethane sulfonate and amphoteric surfactant didodecylmethylcarboxyl betaine along with their different combinations has been investigated in 0.1 M salt solutions at 313 K. The surface chemical parameters of the mixture were also calculated. The results show that the critical micelle concentration (CMC) and γ CMC of the mixture are always lower than those of the individual surfactants, which indicates synergistic effects between the surfactant molecules. The interfacial tension of the Chinese Shengli crude oil and the connate water can be reduced to 5 × 10 −3 mN · m −1 at 70°C with the mixture of alkylated diphenylmethane sulfonate and didodecylmethylcarboxyl betaine.

Washing machines in Europe have to comply with regulations fixed in the Energy Label and Ecodesign legislation. They require declaration of the specific consumption and performance values which are deduced as average values from tests on three different treatments. Detailed data about the individual tests are normally not available to the public but just kept in the technical documentation of the manufacturer. Within the ATLETE II project 62 washing machines were measured to verify their compliance with the declared value. As this was an EU funded project all data are now also publicly available. This set of detailed measured data was used first to get a deeper inside into the performances and consumption values of the specific parameters and second to see how different the approaches are between manufacturers to achieve the same or similar declaration values. Additionally it could be shown that there are significant differences between those programmes used for the declaration and those offered as “normal” programmes to the consumer.

In this paper we report on the rate of oxidation of ethyl mercaptan and its dimer ethyl mercaptan disulfide by alkaline hexacyanoferrate(III) along with its mechanistic pathway, spectrophotometrically. The influence of different experimental parameters, such as change in concentration of EtSH, HCF, OH − and reaction temperature was studdie. It was observed that the order of reaction decreases in [EtSH] or [OH − ] from first order to higher concentration, but it certainly did not tend towards zero order. The effect of surfactants on the rate of reaction was observed at the critical micelle concentration (CMC) of the surfactant and reported to be below the CMC. The investigators, thus, concluded that the added products have an insignificant effect on the reaction rate. Further, the activation parameters were evaluated which lend support to the proposed mechanism. The thermodynamic quantities were also determined and the binding parameters have also been evaluated using the Menger and Portnoy model.

The present paper describes the kinetics of oxidation of p -chlorobenzaldehyde by chromic acid in aqueous and surfactant media in the presence of a promoter at 303 K. The rate constants were found to increase with introduction of hetero-aromatic nitrogen base promoters such as picolinic acid (PA), 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen). The product p -chlorobenzoic acid has been characterized by NMR. The mechanism of both unpromoted and promoted reaction paths has been proposed. In presence of the anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant N -cetylpyridinium chloride (CPC) and non-ionic surfactant Triton X-100 (TX-100) the reaction can undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation. Both SDS and TX-100 produce a normal micellar effect whereas CPC produces a reverse micellar effect in the presence of p -chlorobenzaldehyde.