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The hydrogen bonding ability of both water and methanol, together with the occurrence of hydrophobic interactions, makes their solutions nonideal. This nonideality is reflected in both dynamic and thermodynamic quantities at different extent depending on temperature and concentration. The thermal behavior in terms of transport quantities is investigated for different methanol molar fractions by using the concepts of the Stokes-Einstein relation. Starting from the pure compounds, we compare self-diffusion and viscosity data as a function of the temperature for methanol molar fractions XMeOH = 0.22, 0.5, and 0.7. The results are interpreted within the scenario of the mode coupling theory and show that the Stokes-Einstein relation is violated in a different way depending on the solution concentration. [ABSTRACT FROM AUTHOR]

The use of nanostructured materials is increasingly widespread thanks to their particular properties that can improve the performance of devices in various scientific applications. One of them is in the architecture of perovskite solar cells characterized by high photoconversion efficiency values that make them able to compete with silicon solar cells. In this framework, we deposited TiO 2 sponges by reactive sputtering based on a grazing-incidence geometry combined with the local oxidation of species. The deposited material gains 50% porosity in volume through depths of hundreds of nanometers and consists of a forest of uniform rods separated by mesopores (pipelines) arising from the grazing geometry. Many previous studies showed how TiO 2 can improve the efficiency of perovskite solar cells. In this article, we investigated the change of the wettability values of the TiO 2 samples before and after a postdeposition thermal annealing treatment. For comparison, the influence of the annealing on the wettability of the glass substrate is also reported. [ABSTRACT FROM AUTHOR]

By means of a nuclear magnetic resonance experiment, we give evidence of the existence of a fragile-to-strong dynamic crossover transition (FST) in confined water at a temperature TL=223±2 K. We have studied the dynamics of water contained in 1D cylindrical nanoporous matrices (MCM-41-S) in the temperature range 190–280 K, where experiments on bulk water were so far hampered by crystallization. The FST is clearly inferred from the T dependence of the inverse of the self-diffusion coefficient of water (1/D) as a crossover point from a non-Arrhenius to an Arrhenius behavior. The combination of the measured self-diffusion coefficient D and the average translational relaxation time ≤sτT>, as measured by neutron scattering, shows the predicted breakdown of Stokes-Einstein relation in deeply supercooled water [ABSTRACT FROM AUTHOR]

We studied the thermotropic phase behavior of a phospholipid membrane bilayer of dimyristoylphosphatidylcholine (DMPC) under excess water conditions. We also investigated the effect induced by the antimicrobial peptide, gramicidin D (GrD), when inserted into the membrane bilayer. Several techniques were used to collect information on different properties and various spatial and temporal regimes, including differential scanning calorimetry, fixed energy window neutron scattering, pulsed-field gradient nuclear magnetic resonance and molecular dynamics simulations. We obtained data on the main phase transition (gel-liquid crystalline) temperature of the bilayer system and on the long-range diffusion coefficient for both phospholipids and hydration water. Moreover, we demonstrated the effect of transition on microscopic molecular mobility, perpendicular and parallel to the membrane plane. The influence of gramicidin on these properties is also discussed. [ABSTRACT FROM AUTHOR]