Water diffusion in clays
Clays are application relevant layered porous materials. In this context understanding of water diffusion and molecular ordering of water is of interest. In clay particles water is usually intercalated in a form of integer number of molecular water layers. Recently, a theoretically predicted "1.5" layer state has been observed. In this project the local water diffusion in Li-fluorhectorite (at 1, 1.5 and 2 water layer hydration state) will be measured by means of quasielastic neutron scattering at the FOCUS spectrometer at PSI. Furthermore a novel test experiment on the same instrument will be carried out to measure the structure of the water.
Supervisor: Fanni Juranyi
Water dynamics in maize root mucilage
Water scarcity is the main limit to food production worldwide. Recent studies suggest that mucilage exudation by roots helps plants to better tolerate drought. Wet mucilage is a complex hydrogel, which can take up up to 99.9 % of water. Here the diffusion of water will be measured on a molecular scale by quasielastic neutron scattering at the spectrometer FOCUS at PSI. The focus is on the hydration dependence and to find out whether its main component (polygalacturonicacid) plays a determining role in the dynamics or not. This project is a collaboration with the Georg-August-University Göttingen, Germany.
Supervisor: Fanni Juranyi
Definition and evaluation of a precise calibration standard for the reflectometers at the Swiss Spallation Neutron Source SINQ
High-precision measurements of reference samples on the reflectometers Amor, Morpheus and Narziss are needed to establish a new standard for calibrating these instruments, which are used to investigate thin film samples, heterostructures and bio-membranes. The project involves alignment and neutron reflectivity measurements of several (existing) samples, followed by an analysis using standard simulation tools such as Parratt or MOTOFIT. For the measurements 1 to 2 days on each instrument are necessary. The analysis is performed with state-of-the-art software packages.
Supervisors: Jochen Stahn and Thomas Geue.