Soft condensed matter physics is a broad and rapidly evolving activity at the ESRF. It addresses questions concerning the microstructure, kinetics, dynamics and rheology of complex materials such as polymers, colloidal nanoparticles, macromolecules, often in 3-D or under reduced dimensionality. It involves in situ processing, site-selective chemistry and tailoring of molecular assemblies, structural investigations of thin films and membranes as well as diffraction from fibres, small unit cell systems and biological entities. The techniques used include micro-diffraction, time-resolved small- and wide-angle scattering (SAXS/WAXS), X-ray photon correlation spectroscopy and grazing-incidence techniques. Aided by constant progress at the beamlines and ongoing refinement of the probing techniques, one realises that the borderlines with neighbouring disciplines such as life sciences, surface- and interface physics, chemistry and materials science have become increasingly transparent.

This year, the beamlines have progressed in areas including the development of micron- and submicron sized X-ray beams, coherence-preserving optics and two-dimensional detectors with improved spatial and temporal resolution. Important developments at ID2 were the addition of an image-intensified CCD detector enabling small- and wide-angle scattering at a rate of 10 images per second. This was used to study shear controlled polymer crystallisation and humidity-induced structural transitions in DNA. The permanent installation of the Bonse-Hart ultra-small-angle X-ray scattering (USAXS) camera now allows time-resolved measurements of phase transitions and growth kinetics in colloidal systems and large-scale reorganisation phenomena in polymer networks.

At ID13 a second experimental hutch for scanning microbeam SAXS/WAXS is under commissioning and the microgoniometer is now routinely available for crystallography applications and fibre diffraction. Scanning microbeam diffraction from a single polymer fibre with a 100 nm beam has been demonstrated and combined. SAXS/WAXS experiments have been performed during silk extrusion of < 5 micron fibres. Micro SAXS experiments were carried out on systems such as collagen, chromatin and myelin.

The ID10A beamline continues to operate as a multi-purpose high brilliance beamline exploiting the coherence properties of the beam by combining small-angle X-ray scattering (SAXS) and X-ray photon correlation spectroscopy (XPCS) for the study of slow dynamics in complex systems. Using the continuous filling mode of the machine and fast detectors, correlation times as short as 300 ns were measured recently thus definitively bridging the gap between XPCS and the neutron spin-echo method.

The ID10B beamline now provides grazing-incidence diffraction, reflectivity and grazing-incidence small-angle scattering capability on a single instrument including specific sample environments such as a Langmuir trough for the study of liquid and solid interfaces. An upgrade will allow operation up to 22 keV thus opening the possibility to study buried liquid-liquid and liquid-solid interfaces. Structural studies of liquid and complex (colloid, sol, gel) interfaces including studies of antimicrobial peptides with prokaryotic and eukaryotic cell membranes are in progress.

The selected highlights reflect both the wide variety of subjects and the specific strengths of the individual beamlines. State of the art small-angle X-ray scattering at ID2 is illustrated by a study resolving the structural details of live muscle. Microbeam diffraction at ID13 was used to reveal a lamellar twist in polymer spherulites. Lamellar ordering of mineral particles and the phase behaviour of the lamellar phase under shear were discovered and investigated by SAXS at ID2. A combination of small angle scattering (ID10A) and surface X-ray techniques (ID10B) was used to study layering of colloidal particles in the vicinity of the surface of the suspension. The organisation of phospholipid monolayers on the surfaces of pure water and on a mineral gel was studied by X-ray reflectivity and grazing incidence diffraction at ID10B. Finally, the fluctuations of a freestanding smectic liquid crystal membrane were quantified via X-ray photon correlation spectroscopy at ID10A.