Home and personal care products, such as fabric and hair conditioners and shampoos, are often mixtures of di-alkyl chain ionic / nonionic surfactant mixtures. Such formulations exhibit a complex array of microstructures which affect their functionality, formulation, stability, reproducibility, and adsorption properties. It will be shown how small angle neutron scattering, SANS, has made...
In memory of Isabelle, I choose 4 projects realized with her to illustrate how SANS can be used to determine the structure and the kinetic evolution of self-assembled nanostructured hybrid materials. In mesostructured materials made of organic surfactant (CTAB) and inorganic materials (ZrO2), SANS kinetic experiments (with a stopped-flow coupled to SANS) permitted to identify the role played...
In 2005 pressure from the scientific user community and strategic planning for instrumentation at ILL determined that additional Small-Angle Neutron Scattering (SANS) capacity and capability were required. Demand for SANS beamtime was (and still is!) sky-rocketing being the neutron technique with the most diverse scientific community from soft-matter, biology, physics, materials science and...
We all learn in textbooks that contrast variation is a unique possibility that makes SANS so powerful to probe the “extraordinary structure of ordinary things” in soft matter. But there is a clear difference between reading it and experiencing it by itself. As for my part, I discovered it the very first time I came in Grenoble during my pHD when I tried to probe the structural organization of...
The surfactant sodium dioctylsulfosuccinate (Aerosol OT or AOT) is used widely, due to its versatility. It is soluble in water and in oils, and it is surface activity and can act as an emulsifier. There are hundreds of papers and patents every year that feature it. This amount of research provides ample opportunities to study AOT-containing formulations using scattering. Aerosol OT is...
Amphiphilic diblock copolymers self-assemble in water solution in stable and robust polymersomes (vesicles), which combined to a chemical design flexibility make them excellent candidates as drug or imaging agent carriers. The introduction of actuator in polymersomes and the engineering of their targeted cell adhesion are critical issues for the applications of disease imaging and therapy....
Isabelle and I worked together for 20 years. In that time, we published 51 papers that have been cited over 1800 times. The talk will cover highlights from this collaboration including magnetic surfactants, ionic liquid microemulsions and the search for the Holy Grail in the field of surfactants.
Ionic liquid-in-oil microemulsions
J. Eastoe$^\star$, S. Gold, S.E. Rogers, A. Paul, T....
Magnetic iron oxide nanoparticles offer unique magnetic properties attractive for data storage, spintronics, and biomedical applications. Disorder effects are ubiquitous for nanostructured materials and they crucially influence relevant parameters, like the relaxation dynamics and magnetic hyperthermia performance. Despite the technological relevance, a quantitative interpretation of these...
The sample environment is a critical component of research programs in advanced materials, geological systems, biology, and energy-related applications.
Over the past ten years, an increasing number of studies on liquid materials have been carried out thanks to container-free sample handling methods. Techniques based on aerodynamics or electromagnetic levitation have created new opportunities...
A few examples of experimental studies of soft matter systems will be presented to illustrate some aspects of the personal and scientific journey of Isabelle Grillo. I have met Isabelle for the first time almost twenty-five years ago in the Bombannes school, and since then a combination of geographic coincidence, common scientific topics – from surfactant systems to polymer nanocomposites -,...
Soft materials, such as foam and emulsion systems, which respond to external stimuli, are on the leading edge of materials research and have recently been of interest to many scientists, such as Isabelle Grillo. The macroscopic responsivity relies on the ability to react at microscopic or mesoscopic scales. Stimuli-responsive surfactants that can change their structure in response to a trigger...
Beyond electrostatic, the interaction of ions with their close environment depends on their hydration shell and the water dynamic in this environment. Non-negligible water mediated effects can indeed influence many physical chemistry processes such as cloud point, protein salting-in or out, bubble coalescence, the topology of bilayers... They are thus qualified of "ion specific".
During the...
In 2003, Isabelle Grillo published a highly publicized article on Le Pastis, analyzing with SANS the large-scale structure of droplets responsible for the famous milky appearance of this Mediterranean drink. At the same time, the seminal article of Vitale and Katz on the “Ouzo effect” appeared. These two references kindled an ever-growing field of applied and fundamental research. Isabelle...
Isabelle was deeply fascinated by the beauty of many simple things, including unspoiled natural landscapes and the beauty of the self-assembly of amphiphilic molecules. To honor her memory and send her a wink, I will tell you a short light-hearted story where these two passions once met.
But before that, I would like to share with you some recent results that illustrate how self-assembly...
Ionic liquids (ILs) are molten salts that are liquid at relatively low temperatures. They are composed of sterically mismatched ions that hinder crystal formation and are often defined as salts with melting temperatures below 100 °C, though many are liquid at room temperature and below [1].
Recently, there has been great interest in ILs as their unusual combination of properties, such as,...
Additives are used in lubricant systems to minimise destructive processes in the engine (e.g. wear and corrosion) and to confer beneficial properties (e.g. more uniformed viscosity with temperature and improved fuel economy). Lubricant formulations typically up to 10 ingredients, comprising mixtures of amphiphilic species: surfactants, polymers, sols and inorganic salts dispersed in...
The journey together with Isabelle started 20 years ago in February 2000 at D22. The goal of these studies was to find the mechanism behind the dramatic enhancement of the solubilisation efficiency of ordinary surfactants obtained by adding only traces of amphiphilic diblock copolymers. Performing high-precision two-dimensional contrast variation SANS measurements [1] we could demonstrate that...
or how to do a very elegant and simple hand cream
To illustrate the title of Isa's tribute "the extraordinary structures of ordinary things", I will present Isa's latest personal research work in which I had the chance to participate. Her study focused on the structure of complex solutions obtained from essential oils, micelles of pluronic and from hyaluronic acid. Her goal was to make...
Regulating fat (dietary lipid) digestion to tackle the ongoing obesity crisis has become a pressing issue. Bile salts (BS) are biosurfactants produced in the liver and released into the small intestine, which play key roles in lipid digestion and absorption: they facilitate enzyme adsorption to fat droplet interfaces and remove insoluble lipolysis products from the interface, carrying them to...
Nanovectors are used for delivery purposes in many fields. First developed for biomedical and pharmaceutical applications, they have recently been extended to large scale processes and agriculture. Although soft matter materials such as lipids and polymers are generally considered biocompatibile, in recent times concerns have been expressed regarding the sustainability of the whole process...
The intrinsic stiffness of polyelectrolytes plays an essential role in the structure of their dense solutions and the ones of interpolyelectrolyte complexes.
First, we will report SAXS and SANS experiments performed on dense aqueous solutions of highly charged polyelectrolytes that reveal the existence of an Onsager transition preceded by a new regime, both depending on the intrinsic stiffness...
Knowing the refined structure of complex crude oils and the mechanisms of actions of these structures is of a central interest to understand and predict the behaviors of the petroleum fluids for many industrial applications: oil production, transportation and refining, enhanced oil recovery or gas sequestration. Crude oils are well known to be complex mixtures made of many different...
Self-assembled systems composed of surfactants, copolymers, and/or polyelectrolytes exhibit a large variety of different structures in aqueous solution that depend in a subtle way on the molecular structure of the components, the composition of mixtures, concentration, and external parameters such as pH, ionic strength, temperature, etc.
The formation of such self-assembled structures is...
We had the privilege to collaborate time to time with Isabelle. We have been able to appreciate her exceptional scientific and human qualities. We had a common interest deciphering colloidal “portrait de phases” of mixed systems involving clay platelets and other partners such as magnetic spherical particles [1] or surfactant lamellar phases [2-3]. These works have paved the road to new...
Polyelectrolytes (PEs) are polymers with ionisable groups that dissociate in water. This water-solubility is a remarkable property commonly used in industrial formulations (thickener, gel…). The presence of electrical charges opens up additional possibilities trough the formation of electrostatic complexes with oppositely charged species (colloids, surfactants, PEs, proteins…) leading to new...
Most of the commonly used Ionic Liquids (ILs) contain bulky organic cations with suitable anions. With our COMPLET (Concept of Melting Point Lowering due to Ethoxylation), we follow a different approach. We use simple, low-toxic, cheap, and commercially available anions of the type Cx(EO)yCH2COO– to liquefy presumably any simple metal ion, independently of its charge. In the simplest case, the...
Isabelle's Grillo PhD goal in 1998 was to explore the conditions and therefore the limits of mixing synthetic anionic clays and all known types of surfactant-based lamellar phases: anionic, nonionic and cationic.
Only a fraction of the conditions of mixing, including osmotic pressure compatibility, adsorption and depletion effects were understood at that time. Isabelle Grillo published...
The immobilization of molecular catalysts in confined geometries of mesoporous support materials has been shown to selectively control the catalytic performance. An additional increase in yield and selectivity of catalytic reactions are expected by combining the spatial confinement of the pores with that of a thin ionic liquid film at the pore surface. Small angle X-ray scattering (SAXS) can...
By adding small amounts of amphiphilic diblock copolymers like poly(ethylene oxide)-co-poly(ethylene propylene) (PEO-PEP) to water – oil – non-ionic surfactant systems, Jakobs et al. showed that the efficiency of medium-chain surfactants to solubilize equal amounts of water and oil can be strongly increased (so-called efficiency boosting) [1]. In order to obtain a similar boosting while...
With global warming, green chemistry has experienced a great development. In this context, fatty acids are surfactants of particular interest since they can be extracted from agricultural resources. The use of an organic counter-ion enables their solubilization in aqueous solution at room temperature where they self-assemble into different supramolecular structures.
Stearic Acid (SA), one of...
Planet Earth is about 4.5 billion years old. In this study, we focused on the membranes of the first forms of living entities that assembled from a set of simple molecules available on the prebiotic Earth. The lipid membrane is a structure formed by hydrophobic or amphiphilic biomolecules called lipids, which are used in living organisms for many purposes, as a barrier between the interior of...
Chitin, which is mainly found in arthropods such as insects and crustaceans, is the second most abundant biopolymer besides cellulose.[1] Although about 1000 billion tons of chitin are produced in the biosphere every year, it is barely used to produce high-value products due to its difficult processability.[2] One promising approach to obtain such high-value products is the use of chitin...
Hydrogels are at the forefront of scientific attention especially in the biological and biomedical fields where they provide the basis for stimuli-responsive artificial tissues, vehicles for drug delivery or biosensors. We study physically crosslinked hydrogels based on ionenes, positively charged polyelectrolytes, for which strong counterion-specific effects have been observed previously [1]....
