1. Dynamics of nanofluids
Nanofluids have been discovered in recent years. They consist of a base liquid in which nano-objects of different shapes, dimensionality and properties (for instance, nanoparticles, nanotubes or graphene sheets) are immersed. Nanofluids show enhanced thermal conductivity and electrical capacity – this is one of the reasons for the high interest they attract. Their thermal properties are strongly dependent on the composition of the nano-objects; in recent years nanofluids containing graphene are a matter of extensive debate due to the excellent thermal conductivity of graphene and the large surface contact. Moreover, by inserting into the base liquids even a very small amount of nano-objects significantly influences the fluid dynamics. This effect depends on the dimensionality of the objects (diamagnetic nanoparticles are considered as 0D objects, nanotubes -1D and graphene sheets -2D) and their surface properties as well as structural and dynamical properties of the base fluids (our investigations are carried out for both molecular and ionic liquids). To our knowledge dynamical properties of nanofluids have not been so far investigated on the molecular level (results available in the literature concern only macroscopic, rheological properties of nanofluids and the observed changes in the viscosity of the base fluids cannot be explained in terms of hydrodynamic laws. Profiting from the potential of NMR relaxometry the group carries out investigations on nanofluids consisting of base fluids and nano-objects of various structures in order to unreveal molecular (atomistic) mechanisms leading to the changes of their dynamics. As far as this subject is concerned, we also collaborate with the Joint Institute of Nuclear Research employing neutron scattering methods.
2. Properties of electrolytes
The next topic of our interest is dynamical properties of liquid electrolytes in confinement. In these studies we apply the theoretical description of spin relaxation processes in ionic systems of complex structure (containing different kinds of nuclei – for instance, 1H, 19F or 31P) undergoing translational and rotational diffusion. The goal of these studies is to get insight into the dynamical properties of cations and anions which are depend on their size and structure and explain on the molecular level the influence of the confining walls on the ionic dynamics. The studies are carried out in collaboration with Ionic Liquid and Solid State Ionics Laboratory, Department of Physics, Banaras Hindu University, India. Such studies are relevant from application viewpoint , for instance, the subject of ionic transport inside nanoporous electrodes – in batteries and other energy storage systems. Independently of the applications this field poses in our opinion, interesting questions for fundamental research. For instance, the one 1D (one-dimensional) geometry implies that the passage of molecules undergoing translational dynamics is impossible (or at least very difficult). Mathematically, this sub-diffusive mechanism of the translational motion is reflected by a quantity referred to as a mean squared displacement (MSD) – for free, 3D diffusion this quantity is a linear function of time MSD 
, while for 1D diffusion it is theoretically predicted MSD
(single file diffusion). To our knowledge so far there are no experimental examples allowing for a verification of the concept of 1D translational diffusion for ionic liquids available in the literature. We have observed the single file diffusion effect by means of NMR relaxometry.
3. Dynamics of biomolecules
The next topic is dynamics of biomolecules in solid phase and in solution investigated by means of proton (1H) and deuteron (2H) spectroscopy as well as 2H relaxometry. The research is focused on dynamical properties of liquids confined in biomolecular matrices; they include liquids of high viscosity undergoing glass transition inserted into matrices formed by selected biomolecules (proteins, peptides). These systems show some similarities to liquid electrolytes under confinement. The main question concerns the origin of the differences between dynamics of liquids in bulk and in the matrices and the role of the properties of the liquids and of the biomolecular confinement. This question is a part of a more general subject that is the specifics of the dynamical processes and binary systems and systems under confinement. Biological functions of molecules are intrinsically related to their dynamics – this explain the interest raised by, for instance, the controversy over the „fragille- to-strong transition”, i.e. a rapid change of the character of the dependence of rotational correlation times of proteins on temperature, reported in the literature by some authors and denied by others. To interpret the results of 2H spectroscopy the theory based on Stochastic Liouville Equations (SLE) is applied. The SLE theory enables an analysis of 2H NMR lineshapes for arbitrary time scale of dynamical processes (that is of primary importance for biological systems). Another example of studies of macromolecular systems is dynamics of dendrimers (branched polymers applied, among other, as carriers for targeted drugs). Dendrimers due to their branched structure form “natural matrices” (a geometrical confinement) for small molecules.
4. Properties of food products
NMR relaxometry offers the possibility to monitor subtle changes in the dynamics of food products undergoing different technological procedures. The group has begun such studies focusing on identification and explanation (on the molecular level) of dynamical processes characteristic of food products and establishing relationships between the molecular scenario and the macroscopic, physical and chemical properties of these systems. On the basis of NMR relaxation experiments we intend to identify a set of parameters that can be treated as markers of the food quality and state.
Other research activities are listed in the section “Undergoing projects”.