Sorption hysteresis in random porous materials. Measurement of gas adsorption is a characterization technique routinely applied in any lab. Therefore, the understanding of all features of sorption behavior is of crucial importance. One of the unresolved problems in this respect, intriguing scientists for more than one century, is the phenomenon of sorption hysteresis in disordered mesoporous materials. To get deeper insight into sorption behaviour and hysteresis in such systems, we are experimentally exploring relationships between microscopic and macroscopic dynamics of fluids in mesoporous hosts as probed by means of nuclear magnetic resonance (NMR). More ...

Freezing and melting in disordered pores. Freezing and melting processes of liquids occuring in mesopores closely resemble the main features of desorption and adsorption transitions, including the formation of hysteresis. NMR cryoporometry provides a tool to study their various aspects. In particular, it allows to trace the transition kinetics, analysis of which may yield an important information on the microscopic mechanisms of the transitions. More ...

Correlating phase state and transport in mesopores. As one of the general results of our activities in the areas described above, it naturally has appeared that phase state and transport in mesoscopic systems are strongly correlated. Currently, we are exploring the option to use molecular diffusion as a tool to probe the phase state in small pores. On the other hand, these correlations could be considered as an interesting route to control transport via phase state. This becomes of special interest in materials with hierarchical pore structures. More ...

Transport of supercritical fluids in mesopores. Chemical technology is permanently questing for alternative media for chemical reactions replacing the pure gas or liquid phases. Among them, supercritical fluids are considered to be especially attractive. Their optimal use in processes involving porous solids, however, is rather limited due to our poor knowledge about their transport properties under confinement. By using the non-invasive pulsed field gradient NMR, we are able to directly assess molecular diffusivities of organic fluids in mesopores at sub- and supercritical temperatures. More ...

Structure-dynamics relationship in porous materials. Although general features of molecular transport in macro- and microporous materials are fairly undersood, those in the materials having mesoporous building units are still to be explored. This is primarily determined by complex phase behavior of the confined fluids, typical of these materials, which is stroungly coupled to their transport properties. On the other hand, a sufficiently small ratio of the molecule-to-pore diameter may lead to the changes in the elementary mechanisms of microscopic dynamics. More ...