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The present study demonstrates how the evaporation of a ternary ethanol–water–fragrance solution leads to a transition from an unstructured ternary ethanol-rich solution, to a structured water-rich solution by crossing the so-called pre-ouzo region of its phase diagram. The exothermal nature of this self-assembly revealed by calorimetry suggests that it is coupled to molecular transfer between coexisting micro-domains. Surprisingly, fragrance evaporation is first accelerated in the pre-ouzo region as evidenced unambiguously by simultaneous on-line gravimetric, calorimetric and gas chromatographic monitoring during drying. Upon further drying, a transition from the pre-ouzo to the two-phase turbid region of the phase diagram is observed as the loss of water becomes more important that of ethanol. At this stage, the size of the fragrance-rich domain increases by three orders of magnitude as fragrance droplets surrounded by ethanol molecules are entrapped in water-rich external media and the fragrance evaporation is depressed. This initial acceleration and subsequent retardation of the evaporation kinetics of fragrance molecules are general for all perfumery ingredients. The path of the compositional change in the phase diagram during evaporation is investigated under strong inert gas flux for the first time to our knowledge by two combining on-line methods. [ABSTRACT FROM AUTHOR]

Abstract: Recent progresses in the understanding of properties of catanionic surfactant aggregates are reviewed. These aggregates are charged micro-crystals produced upon co-crystallisation of anionic and cationic surfactants without excess salt. They were studied applying methods developed for polyelectrolyte multilayered capsules. They have been observed without special preparation by soft X-ray microscopy. Confocal optical microscopy allowed first measurements of the diameter of the holes present at vertices. These observations could be rationalized by identifying the formation path in the phase prism. Rigidity was measured directly using the colloidal probe method and calculated using mesoscopic modelling. These progresses made within of the French–German network are discussed versus recent results obtained by other groups working on catanionics. [Copyright &y& Elsevier]

The studies of temperature dependent transitions of bilayer structures are mainly focused on phospholipids systems. Since the appearance of catanionic surfactants it is possible to study another type of bilayer structure but as they were prepared until recently in the presence of initial counter-ions, the electrostatic interactions could not be taken in account. Our aim is to present some differential scanning calorimetry results of salt-free catanionic systems prepared with acid surfactant and hydroxide surfactant, and to compare them with literature data. [Copyright &y& Elsevier]

Abstract: We show that nanodiscs stabilized with polymers order and pile up on a surface upon drying. The resulting surface films with an average thickness of one micron are made of collapsed cohesive layers with smectic long-range order. This occurs with and without plastifying stabilizing polymer and produces crevasses. The stacked discs undergo a two-to-three-dimensional crystallization while bottom layers close to the surface fuse and produce infinite bilayers. Small angle X-ray scattering experiments demonstrate that excess polymer is segregated from the crystalline stack. Water adsorption isotherms show that reversible swelling of the excess polymer does not destroy the compact stack of partially fused nanodiscs collapsed parallel to the surface. In the absence of chemical binding, the stacks of layered nanodiscs can be removed by simple washing with pure water. AFM, TEM and SEM experiments demonstrate that presence of crevasses is quenched by the presence of a plastifying polymer. [Copyright &y& Elsevier]

Abstract: We report on wide angle X-ray scattering (WAXS) and density experiments performed on the ganglioside GM3 in water solution. As compared to what usually found in lipid assemblies, GM3 bilayers show a degree of cooperativity feebler in the region of the lipid chains and stronger in the region of the headgroups. The collected WAXS spectra indicate the existence of a strong degree of order on the molecular scale, which we propose to be due to a highly constrained and symmetric disposition of the trisaccharide charged headgroups of GM3 at the bilayer surface. It is the first time that such an order in the headgroup region is seen in dispersed lipid assemblies, in normal pressure conditions. Experiments were carried out with no added salt, in the semidilute range of concentration, 5–15% bw, and in the range of temperature from 15 to 60°C. Parallel SAXS experiments indicate that on the scale of the bilayer cross section the same structure is preserved from the very dilute (0.1%) to the semidilute range of concentration. [Copyright &y& Elsevier]