Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Emerging Topics in Chemical and Polymer Physics, New Instruments and Methods

CPP 11.3: Vortrag

Montag, 1. April 2019, 15:30–15:45, H8

Container-free sample environment for neutron scattering — •Sebastian W. Krauss¹, Ralf Schweins², Andreas Magerl³, and Mirijam Zobel¹ — ¹University Bayreuth, Bayreuth, Germany — ²Institut Laue Langevin, Grenoble, France — ³Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany

In-situ small angle X-ray and neutron scattering (SAXS / SANS) provide valuable insights into soft matter systems, such as micelles, biological macromolecules or nanoparticle (NP) formation. For SAXS free-jet setups are established, but the counterpart for SANS was missing, as SANS requires large sample cross sections^[1]. Here, we introduce a novel free-film setup, where the neutrons only penetrate a flowing liquid film optimized to a sample area of 7x10 mm² with a typical film thickness of 0.5 mm as determined from the incoherent scattering of the film. In order to suppress H/D-exchange from the humidity in the air for the operation of the setup with deuterated solvents, we jacketed the setup in a containment filled with Helium. To validate the H/D-ratio over time, three independent methods have been used: IR, gravimetry, incoherent neutron scattering. The main benefit of the free-film is the reduction of the background scattering by 37 % in comparison to measurements in a standard Hellma cell as typically used for SANS. Furthermore, we showcase the setup for the formation of EDTA-capped CdS nanoparticles, in order to investigate the role of the weakly scattering EDTA ligand shell in the nucleation process, having been inaccessible so far.

[1] Lopez, C. G., (2018). J Appl Crystallogr 51, 570-583.