NMR studies on the molecular dynamics of hydrogen bonded liquids in nanoscopic confinements

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In this project, we intend to investigate hydrogen bonded liquids in nanoscopic confinements using NMR experiments. In particular, we will ascertain the molecular dynamics of the confined liquids as a function of the size, hydroaffinity, and softness of the confining geometry, considering the possibility of complex phase behavior. In the course of the project, the complexity of the studied guesthost systems will be increased, proceeding from simple to complex fluids and from homogeneous to heterogeneous confinements. In this way, knowledge transfer from simple models to elaborate materials will be ensured. At the beginning, the studies will focus on water-alcohol mixtures in confinements of well-defined size, hydroaffinity, and softness. This approach will allow us to develop a basic understanding of the dependence of liquid dynamics on the properties of the confining geometry against the background of potential microphase segregation at interfaces. Afterwards, it is planned to consider increasingly complex guest-host systems. At the end, we will deal with proteins residing together with water and cosolvent in a disordered matrix provided by macromolecular crowders. For the latter systems, the relations of short-ranged and long-ranged dynamics and the couplings of protein and solvent motions are to be understood, which play a decisive role for biological functions. Our studies intend to exploit the capabilities of NMR. The isotope selectivity of the method will allow us to separately ascertain confinement effects for the molecular dynamics of the individual components of the considered mixtures. In doing so, it will be utilized that motions in wide dynamic ranges and broad temperature intervals are accessible when combining various NMR techniques. Moreover, we will make use of the fact that NMR experiments, in particular, stimulated-echo experiments, provide insights into not only the rates, but also the mechanisms for molecular dynamics. Finally, we will take advantage of the possibility to investigate motions on various length scales, when performing NMR experiments in both homogeneous and inhomogeneous magnetic fields.