Technical activity on D. Lairez

Measuring Zeta potential of nanochannels wall

Sat, 01 Jul 2023 00:00:00 +0000

In the study of the transport properties of electrolytes through nanochannels , surface effects become very important. One of them concerns the interactions due to electrostatic charges that may be present on the surface of the channels-wall. Being able to measure the electrical potential that these charges produce at a distance from the wall (namely the Zeta potential of the wall) is often crucial for the understanding and improvement of membranes properties.

Modeling the equilibrium shape of adsorbed vesicles of lipid bilayers

Fri, 01 May 2020 00:00:00 +0000

Lipid bilayers are often taken as experimental models for biological membranes. In many cases, the investigation of their biochemical properties, such as their chemical affinity for one or the other conpound, is carried out either on adsorbed vesicles or on bilayers supported by solid subtrates. For these studies, neutron reflectivity is an exceptional tool (see for instance the impresive list of experiments in this field that have been done on MARIA neutron reflectometer ). However, with neutron reflectivity the data analysis (in jargon “data fitting”) is really a tricky problem. Reducing the number of free parameters is crucial. In the case of adsorbed vesicles this can be done by modeling the equilibrium shape that they adopt depending on some physical parameters (rigidity, adsorption constant, size etc.).

Neutron scattering

Wed, 01 Apr 2020 00:00:00 +0000

Neutron scattering techniques are privileged tools to probe soft matter. This is mainly due to their strong interaction with protons (H¹) which differs widely from that with deuteriums (H²), allowing the labelling of organic molecules.

These techniques are not the only ones I have used and developped for my own experimental researches . But in parallel to these from 1993 to 2019, it was a part of my job at Laboratoire Léon Brillouin (the french neutron research facility ) to host scientists from all over the world to perfom their experiments on the small angle scattering spectrometer PACE and latter on the time-of-flight reflectometer HERMES and to guarantee the quality of the measurements they made there.