Volume 47, Issue 5

We measured interfacial tensions (IFT) of aqueous alkyl polyglucoside (APG) systems formulated with sorbitan ester-type cosurfactants against n-octane. The study focused on low to ultra-low IFT systems which are relevant for enhanced oil recovery (EOR). In addition, we measured equilibrium adsorption concentrations of these surfactants and cosurfactants onto kaolinite clay, commonly found in oil reservoirs. We present one surfactant EOR laboratory flood experiment with one selected APG-sorbitan ester formulation with which we recovered 94% of initial oil in place (IOIP).

Cationic biodegradable gemini surfactants 3,8-diaza-4,7-dioxodecane-1,10-diylbis(alkyldimethylammonium bromide) (I) with R = C 9 H 19 –C 18 H 37 inhibited photosynthetic electron transport (PET) in spinach chloroplasts and reduced chlorophyll (Chl) content in Chlorella vulgaris. The inhibitory effects of I intensively depended on the length of alkyl chain showing quasi-parabolic (Chlorella vulgaris) or bilinear (PET) course. IC 50 value related to reduction of Chl content in C. vulgaris for dodecyl derivative was 0.6 × 10 −6 mol dm −3 indicating its strong anti-algal effect. Using EPR spectroscopy as the site of inhibitory action of I in the photosynthetic apparatus the intermediates Z ∗ and D ∗ or their close surroundings were determined. As a further target of I inhibitory action the manganese cluster occurring on the donor side of photosystem II was estimated.

Design and synthesis of a new galactolipid 6 with carbamate was described in this work. Compounds 1–3 were obtained easily with classical synthesis methods which were improved a little. The influence of the solvent and different groups of the tertiary amine 4 for the quaternization reaction was discussed. The mixture of chloroform, ammonia and methanol was used well as the elution for separating compound 5 with silica gel column chromatograph. The CMC and γ CMC was 2.40 · 10 −4 mol/L and 26.1 mN m −1 , respectively by surface tension measurement. Vesicles can be formed according to the theory of critical packing parameter since the value of the critical packing parameter was 0.83 at CMC, and it was confirmed by TEM micrograph.

Phase behaviour and static structure of surfactant systems have been studied in much detail, but this applies much less so to their dynamic properties. Structural transitions in amphiphilic systems can be triggered by mixing different amphiphiles. Employing the stopped-flow technique we have studied the kinetics of formation of multilamellar vesicles starting from a micellar solution and a microemulsion containing a semipolar oil. This process has been investigated for various starting conditions and as a function of the charging of the amphiphilic system. The formation process is the faster the closer the starting solution is in composition to the final state and can be slowed down by the presence of ionic surfactant.

Bicontinuous microemulsions are investigated as a model system for the specific adsorption phenomena of metal ions at the water-oil interface. Mixing an extremely hydrophobic ion extractant – tributyl phosphate (TBP) used here as co-surfactant – with an extremely hydrophilic sugar-based surfactant, we describe a new type of functionalized microemulsions that shows the classical Winsor phases, by varying the surfactant/extractant ratio. We focus on the Winsor III-type microemulsions by determining the phase diagrams whereas the microstructures were accessed by performing small angle neutron scattering experiments. Ultimately, these microemulsions may pave the way for the design of new selective ion extraction processes.

Water/propylene glycol/sucrose laurate/ethoxylated mono-di-glyceride/isopropylmyristate microemulsion systems were formulated and investigated using electrical conductivity and small angle X-ray scattering. The solubilization capacity of water in oil is dependent on the surfactants mixing ratio (w/w). The free energy of solubilization (ΔG o s ) values for water-in-oil microemulsions were calculated and found to decrease with water content in the water-in-oil microemulsions, they decreased with increasing ethoxylated mono-di-glyceride content in the mixed surfactants. The activation energy of conductive flow was estimated and a percolation phenomenon was revealed in these systems. Small angle X-ray scattering results indicate that the periodicity increases linearly with the increase in the water volume fraction in these microemulsions. The correlation length increases with the increase in the water volume fraction to a certain value then decreases.

By means of surface tension measurement (ring detachment method) mixed micellization and mixed adsorbed film formation were studied between an amphiphilic drug (amitriptyline hydrochloride – AMT) and nonionic surfactants (Tritons and Tweens) at different mole fractions. From the equilibrium surface tension measurements critical micelle concentration (CMC), maximum surface excess (Γ max ) and minimum area per surfactant molecule at the air/solution interface (A min ) were obtained. The theories of Rosen, Rubingh and Maeda were applied to analyse the results. Different thermodynamic parameters, viz. free energy of micellization (ΔG o m ), standard Gibbs energy of adsorption (ΔG o ads ), and minimum energy of surface (G min ) were evaluated. In the mixed micelles, presence of nonionic surfactants between the head groups of drug molecules decreases the repulsion among head groups. As a result, the CMC and Amin decrease while Γ max increases. Interaction parameters of micelles (β m ) and monolayer (β s ) indicate that the drug surfactant systems show better interaction at the interface than in micelles.

Ordered ferrocene-containing mesoporous hybrid materials were prepared by the use of quaternary ammonium surfactants C n H 2n+1 (CH 3 ) 3 NBr and organic additives during the hydrothermal synthesis process. The characterization results showed all the materials exhibit an ordered two-dimensional hexagonal pore structure with pore diameter from 2.04 nm to 4.01 nm. It was found that the pore diameter of the materials is strongly dependent on the surfactant chain length and the content of the organic additives. The fourier transform infrared spectra revealed that the organic bridge is preserved during the hydrothermal synthesis and subsequent extraction procedure.

This study presents an overview of four international test standards for domestic dishwashers or dishwashing detergents: the European (EN 50242), the North American (AHAM), the Australian (AS/NZS) and IKW standard. All four standards were used to test five different dishwashers and two kinds of dishwashing detergents under standardised laboratory conditions to see if they deliver comparable results. Furthermore the practicability and selectivity of the different soiling and evaluation procedures were assessed. Additionally to a general comparison of the four standards, the focus lay on the soil egg yolk. The study shows that the general ranking between the dishwashers is similar, but the cleaning results of the individual soils and the performance levels differ a lot. Only the IKW soils are suitable to make a clear distinction between the detergents. Whereas the machines can be – more or less – distinguished with all standards except AS/NZS standard. Possible reasons for the varying results can be found in the different amounts of soil, the preparation methods or the cleaning performance evaluation, which shows the importance of designing accurate testing procedures for dishwashing.

The focus of this paper is to show an approach on how to optimize manual dishwashing. After presenting the method developed for simulating a repeatable manual dishwashing process, the report shows the results of the experimental study exploring the main impact factors for the optimization of the water consumption by applying a mathematical regression model. These experiments demonstrate that the water changes in the main washing bath and the water changes in the rinsing bath are significantly affecting the cleaning performance of the dishes. Concentration of cleanser is found to have a negative quadratic effect, and the interaction effect of the number of water changes in the rinsing bath with the amount of detergent (respectively Concentration of cleanser) is found to be significant. As an explanation of this behaviour, it is suspected that soil particles are transferred through foam residuals, which are not washed off in the rinsing bath. Because of several restrictions, such as having limited statistics and having excluded possible impact factors, the developed model aims at depicting tendencies of the impact factor effects and may not be generalized.