From: 2025-05-14 14:15 to 15:00
Place: Lecturehall KC:F
Contact: andrea [dot] scotti [at] fkem1 [dot] lu [dot] se

A COMMONS seminar by Adjunct Professor Giovanna Fragneto, Physical Chemistry, Lund University.

 Title: Neutron and Synchrotron Radiation study of charged bilayers

When: 14 May 2025, 14:15-15:00

Where: Lecturehall KC:F, Zoom: https://lu-se.zoom.us/j/66632888718

The seminar will revolve around the use of neutron and synchrotron radiation reflectometry measurements of fully charged floating bilayers in bulk water [1] and trilayers [2] in controlled humidity environment. Neutron and X-ray reflectivity experiments show that the water layer between like-charged bilayers is thinner than for zwitterionic lipids, demonstrating the existence of counterintuitive electrostatic attractive interaction between bilayers. 
Experimental measurement of the water thickness, combined with precise determination of charged surface positions by numerical simulations, enable to compare experiments with a theoretical model showing that charge-screening by hydration water induces Strong Coupling attraction, even at moderate surface charge densities with monovalent counterions.
The findings offer insights into the forces that control interactions between phospholipid layers and have important implications for biological and colloidal systems.

[1] Attractive Interaction between Fully Charged Lipid Bilayers in a Strongly Confined Geometry
Tetiana Mukhina, Arnaud Hemmerle, Valeria Rondelli, Yuri Gerelli, Giovanna Fragneto,  Jean Daillant and Thierry Charitat
J. Phys. Chem. Lett. 2019, 10, 7195−7199

[2] The role of confined water in the emergence of electrostatic strong coupling as revealed by nanoseparated charged lipid layers Swen Helstroffer, Ludovic Gardé, Giovanna Fragneto, Arnaud Hemmerle, Léo Henry, Laurent Joly, Fabrice Thalmann,†Claire Loison, Pierre Muller and Thierry Charitat submitted to J. Phys. Chem. Lett.