The molecular structure of mesoporous solid ionic systems is crucial for optimizing macroscopic properties, in particular ionic transport for energy applications. It will be shown how the combination of SAXS and SANS can be used to extract quantitative structural information on the nanoscale by appropriate rescaling in both contrast and scale. We report on the structural analysis of ionic...
Hydrophobic additives, such as essential oils or fragrances, can have a tremendous impact on the viscosity and viscoelasticity of aqueous surfactant gels. The effects are best understood by constructing complete salt curves using sodium laureth sulfate (SLES) in the presence of various additives. A total of four distinct mechanisms of solute-surfactant interactions was identified that...
Certain amphiphilic copolymers form lipid-bilayer nanodiscs from artificial and natural membranes, thereby rendering incorporated membrane proteins optimal for structural analysis. Recent studies have shown that the amphiphilicity of a copolymer strongly determines its solubilization efficiency. This is especially true for highly negatively charged membranes, which experience pronounced...
Oil foams can be used in food, cosmetics, and pharmaceutical formulations, for enhancing textures, improving product application, and delivering active ingredients. Traditionally, they have been stabilized with a high concentration of surfactants that form crystalline particles [1]. Recently, oil foams were produced with hydrocarbon-based surfactants, but without the presence of crystalline...
A long time ago, Thomas Zemb pointed out that a published study had claimed electron densities corresponding to aluminium in the cores of certain surfactant micelles, something that would have been impossible had absolute-scale modelling been applied together with molecular and concentration constraints. I already appreciated the importance of this approach from my work with contrast-variation...
This study focuses into the molecular dynamics of the ternary ethanol-octanol-water mixture, selected for its well-defined structure across critical point fluctuations, pre-Ouzo, and Ouzo phases, with organization occurring on a mesoscopic scale of a few nanometers. Using a combination of Neutron Scattering, NMR, rheology, and classical
molecular simulations, we present a detailed description...
In situ centrifugation introduces a controllable gravitational field directly during neutron or X-rays scattering experiments, making it a new thermodynamic control parameter, on par with temperature, pressure, or magnetic fields. By applying high gravitational accelerations (up to several thousand g), it enables real-time observation of structure and phase evolution in soft matter systems...
Foams appear in many applications such as in personal care products, firefighting and food technology. An elegant tool to tune the foam stability is the addition of polymers of different charge, amphiphilicity or molecular architecture. An example, which will be addressed here are foams which are stabilized by stimuli-responsive microgels.
For understanding macroscopic foam properties, it is...
Combining modalities enables revealing the complexity of matter. After having learnt this lesson from Thomas Zemb while studying colloidal systems with him in the years 2000, i later applied it to completely different fields of research – the latter being the operando investigation of battery materials. In this talk i will emphasize the advantages and necessity of SAXS/SANS techniques coupled...
Adding photocurable polymers to aqueous suspensions of cellulose nanocrystals (CNCs) preserves their structural organization after processing, as recently demonstrated for nanocomposites with gradient chiral nematic structure produced by membrane ultrafiltration and UV-curing [1]. Nevertheless,understanding the physiochemical interactions between the nonionic polymer (PEGDA) and the CNCs is...
The literature indicates that the water surface is negative even at bulk pH well below 7. Our instrument excites, and is able to detect, the capillary modes of macroscopic bubbles with oscillations of minimal amplitude. The surface undulations are amplified at resonance by e.m. waves of 0.2 - 20 V/cm, reaching figures in the range of 0.5-20 nm ($10^{-6}$ times the bubble size). The bubble...
Presumably simple solutions can show a variety of nanoscale aggregation structures. Ternary mixtures of three liquids, in which two show only partial mutual solubility, resemble different types of microemulsions even in the absence of classical surfactants. We present fully atomistic molecular dynamics simulations of octanol/ethanol/water mixtures, a typical representative of these...
Antimicrobial resistance is rapidly increasing worldwide, calling for alternative strategies beyond conventional antibiotics. Silica nanoparticles (SiO₂ NPs) are promising nanocarriers, but their impact on bacterial dynamics at relevant length and time scales remains insufficiently understood. Here, we combine Ultra Small-Angle X-ray Scattering (USAXS) and X-ray Photon Correlation Spectroscopy...
Adsorption of surfactants to fluid interfaces occurs in technological and daily-life contexts. The surfactant surface coverage $\Gamma$ governs interface characteristics like tension $\gamma$, viscoelastic properties, and the stability of thin foam films. Typical experiments merely yield the tension isotherm $\gamma(c)$, where $c$ is the bulk concentration. Parameter-based models of surfactant...
Small-angle scattering (SAS) curve fitting is frequently posed as a rugged, high-dimensional optimisation problem. In many practical cases, closely similar I(q) profiles can be produced by markedly different parameter combinations, highlighting the challenge of parameter degeneracies. Satisfactory solutions are rarely achieved without imposing constraints or introducing prior assumptions about...
There are many examples of synthetic and biomimetic lamellar organisations in surfactant and lipid systems, but there are only a few examples of such membrane multilayers in nature: the myelin sheet in vertebrates, stacked thylakoid membranes in photosynthetic organisms and the lamellar domains of the stratum corneum. Whether synthetic or natural, these examples have in common highly ordered...
