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A fundamental understanding of the doping effect on the hydration mechanism and related proton diffusion pathways are keys to the progress of Proton-Solid Oxide Fuel Cell (H+-SOFC) technologies. Here, we elucidate the possible interplay between the crystal structure upon hydration and the conductivity properties in a promising perovskite type H+-SOFC electrolyte, BaIn0.6Yb0.2Ti0.2O2.6−n(OH)2n. Thermal X-ray and neutron diffractions, neutron time-of-flight scattering along with thermal gravimetric analysis reveal the structural features of BaIn0.6Ti0.2Yb0.2O2.6−n(OH)2n at fuel cell operating temperatures. Between 400–600 °C, BaIn0.6Yb0.2Ti0.2O2.6−n(OD)2n (n ＜ 0.042) remains in a disordered perovskite structure with high anisotropies in the form of oblate spheroids for oxygen. At 400 °C, the presence of oxygen and proton static disorder is clearly established. Yet, the insertion of mobile protons in 24k sites does not induce long-range structural distortion while facilitating both inter- and intra-octahedral proton transfers via quasi-linear O–D…O bonds, strong hydrogen bonding, and octahedral tilting. This experimental evidence reveals that the co-doping approach on Ba2In2O5 enhances greatly protonic conductivity levels by enabling a continuous proton diffusion pathway through BaIn0.6Yb0.2Ti0.2O2.6−n(OH)2n. These new insights into the doping effect on the proton-transfer mechanism offer new perspectives for the development of H+-SOFC electrolyte materials. [ABSTRACT FROM AUTHOR]

If protein structure and functionchanges upon adsorption are welldocumented, modification of adsorbed protein dynamics remains a blindspot, despite its importance in biological processes. The adsorptionof metmyoglobin on a silica surface was studied by isotherm measurements,microcalorimetry, circular dichroı̈sm, and UV–visiblespectroscopy to determine the thermodynamic parameters of proteinadsorption and consequent structure modifications. The mean squaredisplacement and the vibrational densities of states of the adsorbedprotein were measured by elastic and inelastic neutron scatteringexperiments. A decrease of protein flexibility and depletion in lowfrequency modes of myoglobin after adsorption on silica was observed.Our results suggest that the structure loss itself is not the entropicdriving force of adsorption. [ABSTRACT FROM AUTHOR]

Water dynamics in inorganic nanotubes is studied by neutron scattering technique. Two types of aluminosilicate nanotubes are investigated: one is completely hydrophilic on the external and internal surfaces (IMO-OH) while the second possesses an internal cavity which is hydrophobic due to the replacement of Si-OH bonds by Si-CH 3 ones (IMO-CH 3 ), the external surface being still hydrophilic. The samples have internal radii equal to 7.5 and 9.8 Å, respectively. By working under well-defined relative humidity (RH) values, water dynamics in IMO-OH was revealed by quasi-elastic spectra as a function of the filling of the interior of the tubes. When one water monolayer is present on the inner surface of the tube, water molecules can jump between neighboring Si-OH sites on the circumference by 2.7 Å. A self-diffusion is then measured with a value ( D = 1.4 × 10 -5 cm 2 s -1 ) around half of that in bulk water. When water molecules start filling also the interior of the tubes, a strong confinement effect is observed, with a confinement diameter (6 Å) of the same order of magnitude as the radius of the nanotube (7.5 Å). When IMO-OH is filled with water, the H-bond network is very rigid, and water molecules are immobile on the timescale of the experiment. For IMO-OH and IMO-CH 3 , motions of the hydroxyl groups are also evidenced. The associated relaxation time is of the order of 0.5 ps and is due to hindered rotations of these groups. In the case of IMO-CH 3 , quasi-elastic spectra and elastic scans are dominated by the motions of methyl groups, making the effect of the water content on the evolution of the signals negligible. It was however possible to describe torsions of methyl groups, with a corresponding rotational relaxation time of 2.6 ps. The understanding of the peculiar behavior of water inside inorganic nanotubes has implications in research areas such as nanoreactors. In particular, the locking of motions inside IMO-OH when it is filled with water prevents its use under these conditions as a nanoreactor, while the interior of the IMO-CH 3 cavity is certainly a favorable place for confined chemical reactions to take place., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A fundamental understanding of the doping effect on the hydration mechanism and related proton diffusion pathways are keys to the progress of Proton-Solid Oxide Fuel Cell (H(+)-SOFC) technologies. Here, we elucidate the possible interplay between the crystal structure upon hydration and the conductivity properties in a promising perovskite type H(+)-SOFC electrolyte, BaIn0.6Yb0.2Ti0.2O2.6-n(OH)2n. Thermal X-ray and neutron diffractions, neutron time-of-flight scattering along with thermal gravimetric analysis reveal the structural features of BaIn0.6Ti0.2Yb0.2O2.6-n(OH)2n at fuel cell operating temperatures. Between 400-600 °C, BaIn0.6Yb0.2Ti0.2O2.6-n(OD)2n (n < 0.042) remains in a disordered perovskite structure with high anisotropies in the form of oblate spheroids for oxygen. At 400 °C, the presence of oxygen and proton static disorder is clearly established. Yet, the insertion of mobile protons in 24k sites does not induce long-range structural distortion while facilitating both inter- and intra-octahedral proton transfers via quasi-linear O-DO bonds, strong hydrogen bonding, and octahedral tilting. This experimental evidence reveals that the co-doping approach on Ba2In2O5 enhances greatly protonic conductivity levels by enabling a continuous proton diffusion pathway through BaIn0.6Yb0.2Ti0.2O2.6-n(OH)2n. These new insights into the doping effect on the proton-transfer mechanism offer new perspectives for the development of H(+)-SOFC electrolyte materials.

We study the smectic director structure of the rodlike liquid crystal 4-n-dodecyl-4'-cyanobiphenyl (12CB) confined in cylindrical cavities of 200 nm diameter in porous alumina templates by means of combined broadband dielectric spectroscopy, optical birefringence, and neutron scattering measurements. We show that the collective molecular orientation differs between entering the smectic A phase upon cooling from the isotropic state and entering the same phase upon heating while melting the confined crystal. We discuss this collective molecular realignment in terms of a competition between weak planar anchoring at the p-Al2O3/12CB interface and a preferred texture typical of the crystallization of rodlike molecules in nanochannels (Bridgman growth).