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New details on the structure of β-casein adsorbed layers, at the air–water interface, have been obtained using X-ray and neutron reflectivity. The experimental data are fitted well by a power law model and the results discussed in terms of the distribution of amino-acid sequences between trains, loops and tails. This distribution seems to be consistent with statistical theories established for flexible polymers. The trains are present in close proximity to the surface as a dense layer 8–9 A thick. At low surface coverage, the tail effect is negligible and the adsorbed layer is composed of nearly 60% amino-acid sequences in trains and the remaining in loops. When the bulk concentration is increased, a substantial part of the amino-acid residues has to be accommodated in loops and long tails; the adsorbed layer becomes more extended (80–100 A). A striking feature is observed for a high bulk concentration (10−1 wt.%): trains are forced to eject out of the interface.

Langmuir-Blodgett films of mesomorphic side-chain polymethacrylates are investigated from the point of view of their phase change versus temperature via X-ray and neutron reflectivity. Upon heating, “thick” films undergo an irreversible transition towards the well known smectic Al lamellar phase. In contrast a bilayer deposited onto a solid substrate appears to be very stable upon annealing. Such a behaviour is believed to induce an epitaxial mechanism when cooling “thick” Rims from the isotropic melt phase.

The specular reflectivity of x-rays at sufficiently small grazing angles is absorption-coefficient-dependent so that the EXAFS technique can be used to probe the surface. This method allows in situ measurements. Applications to the study of passive films on nickel and nickel-molybdenum alloy electrodes are presented. In both cases, the passive films is found to be composed of NiO entities probably ordered perpendicularly to the electrode. Molybdenum enrichment in the surface layer is confirmed by an increase of the Mo k edge signal.

Amorphous films of some μm in thickness, prepared by low temperature condensation in an ultra-high vacuum onto liquid helium cooled substrates, have been studied in situ by using an X-ray diffractometer operating in a symmetrical reflection mode. The structure factor of gallium has been obtained over the wavevector range 1.3 to 16.1 A − by means of two wavelengths, Cr Kα and Mo Kα , monochromatized by balanced filters. The average number of nearest neighbours deduced from the well-resolved first maximum in the radial distribution function is equal to 9.3 atoms. The results are compared to those previously found by electron diffraction measurements on thin films and also to the structure of supercooled liquid.

X‐ray diffraction measurements up to momentum transfer q=16 A−1 were performed at atmospheric pressure on both the high‐density form of amorphous ice obtained by pressurization of crystalline ice Ih at 77 K up to 2 GPa and the low‐density form obtained by further heating. These two amorphous phases exhibit significant differences at the level of the second‐ and third‐nearest neighbors which involve a decrease of the O–O–O angle on compression at high pressure. Moreover, it is found that the low‐density form is quite similar to that obtained by vapor deposition on cooled substrates at 77 K.

Within the liquid crystalline domain, dihydroxysilicon(IV) octakis(dodecyloxymethyl) phthalocyanine is polycondensed to give a distribution of polysiloxanes. These latter form a mesophase with lamellar order. For the first time polycondensation has been carried out in a columnar mesophase and a new type of oligomeric mesogen has been obtained. The term spinal columnar liquid crystal is proposed to designate such a mesophase.

After a survey of the in-situ techniques used to probe the structure of electrochemical interfaces, we present new results obtained by specular X-ray reflectivity on the liquid-vapor, the liquid-gas and, for the first time, the liquid-water and liquid-electrolyte interface of mercury.

X-ray diffraction measurements were performed at atmospheric pressure on a high-density form of amorphous ice obtained by pressurizing crystalline ice Ih at 77 K, up to 2 GPa. The low--momentum-transfer region of the determined structure factor is quite different from that corresponding to the low-density form of amorphous ice. However, the nearest-neighbor distance and coordination number are almost unchanged. The high density of this form of amorphous ice is explained by the strong distortion of the 0-0-0 angles from the ideal tetrahedral value.

We built a special Langmuir through allowing the use of X-ray reflectivity. Using the device we studied for the first time the density profile of a Langmuir monolayer directly on water. This experiment opens new prospects in particular to measure the roughness of solid films on water subphase.

Noncrystalline solid formamide can be prepared by vapor deposition onto substrates kept at 77 K. A structural investigation of the so-obtained samples using x-ray scattering indicates that there are, on average, four hydrogen-bonds per molecule. The amorphous structure can be described by a short-range order which resembles the one in the crystalline solid.