Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Focus Session: Soft Matter and Nanocomposites: New Opportunities with Advanced Neutron Sources 1
CPP 33.4: Vortrag
Donnerstag, 8. September 2022, 10:30–10:45, H38
In-situ neutron reflectometry measurements of polyelectrolyte diffusion in Layer-by-Layer films in aqueous solution at ILL — •Annekatrin Sill1, Heiko Ahrens1, Olaf Soltwedel2, Philipp Gutfreund3, and Christiane A. Helm1 — 1University of Greifswald, Institute of Physics, D-17489 Greifswald, Germany — 2Technische Universität Darmstadt, Institute for Condensed Matter Physics, D-64289 Darmstadt, Germany — 3Institut Laue-Langevin, F-38042 Grenoble, France
Up to now, we measured vertical polyelectrolyte diffusion in Layer-by-Layer films by immersing the film for a defined amount of time in the annealing solution. Then the film was dried, and a snapshot was taken. With the snapshot method, one can get good results, but we wanted to develop an improved method. For the first time, the dynamics of our films were studied in-situ at the Institut Laue-Langevin (ILL) on instrument D17. This neutron reflectometer with horizontal scattering geometry is suitable for in-situ measurements, using wavelengths from 2 to 27 Å with great flexibility in resolution. We used the slab architecture with selective polyanion deuteration to study vertical polyanion diffusion. As polycation linear PDADMA was used, PSS/PSSd was the polyanion. Each film consisted of a protonated and a deuterated slab. Varied were the salt concentration and the temperature of the annealing solution. The diffusion constant was determined and compared to the snapshot measurements in air.