Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 54: Poster Session 3

CPP 54.1: Poster

Donnerstag, 3. April 2014, 15:00–19:00, P2

Properties of solvent mixture confined between silica slabs — •Xiangyang Guo, Tobias Watermann, Christoph Allolio, and Daniel Sebastiani — Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale)

Firstly, we investigate the anomalous structure and hydrogen bond network of pure water confined between 2 silanol slabs through ab intio simulations. We compute the proton NMR chemical shifts of confined water as a measure for the strength of the hydrogen-bonding network based on a first principle approach. Our calculations illustrate both the modifications of the 1H NMR chemical shifts of the water with respect to bulk water and a considerable slowing down of water diffusion. Furthermore, we perform classical MD simulations on ethanol-water mixture under confinement using the same silica surface model. The diffusion coefficients of water and ethanol in the confined mixture are reported. The computed density profile shows that evident molecular segregation appears in the confined mixture. Ethanol molecules are more likely to form hydrogen-bonds with silica surface whereas most water exists as small hydrogen-bonded clusters at the center of the pore. This observation is corroborated by the wall-solvents radial distribution functions.