Molecular dynamics simulations of water mixtures in confinements

点击翻译按钮获取中文摘要

Using MD simulations, we will systematically investigate the influence of the geometry, hydroaffinity, and softness of a confinement on the structure, dynamics, and phase behavior of embedded hydrogen-bonding liquids. As guest systems, we will use pure water as well as mixtures of water with alcohol, carboxylic acids, peptides, or proteins. The host systems will be varied systematically with respect to geometry, hydroaffinity, and softness. Apart from atomistic pores, we will also use smooth walls in order to confine the liquid. Compared to the first funding period, the project will now focus more on water mixtures than on pure water. Concerning pure water, we will aim at a theoretical understanding of the dynamical slowdown in the vicinity of hard walls, in particular, for neutral confinements that to not alter the structure of water. For this purpose, we will adapt promising approaches such as the random first order theory, the shoving model, and the elastically cooperative activated barrier hopping theory for the glass transition of bulk liquids. We will also look at the wetting and phase behavior of water in partially filled pores. For mixtures of water with alcohol, carboxylic acids, and peptides, we will mainly focus on the influence of geometry and hydroaffinity of the confinement on the phase behavior. We will quantify the interplay of volume and surface effects by using spatially resolved energy and entropy considerations in order to develop thermodynamic models for demixing in confinement. For water peptide and water protein mixtures we intend to investigate the dynamical coupling between the two components under the influence of confinement so as to gain insights into the function of proteins in densely packed biological environments on the basis of suitable model systems.