Quasi-elastic neutron scattering of thermoresponsive surfactant vesicles

In this work, we will explore how vesicle dynamics change in response to different salt and temperature conditions. This will be achieved by preparing various aqueous solutions of a specially synthesised zwitterionic surfactant molecule - oleyl amidopropyl betaine (OAPB) - in predetermined ratios with the well-known anionic surfactant, aerosol-OT (AOT). We then will measure the dynamics and calculate mean square displacement as a function of salt concentration and temperature using quasi-elastic neutron scattering (QENS), to determine changes in conformational entropy, diffusion and flexibility (using MSD).5 This study will expand on our recent published work in the structure of the vesicles using SANS@ANSTO, and will allow us to understand the structure-dynamics correlation in these systems. We will also utilise deuterated constituents of OAPB and AOT (already provided by the National Deuteration Facility (NDF) at ANSTO) to elucidate individual contributions of molecules to the overall dynamics.