The term Soft Condensed Matter applies to polymers, colloids, emulsions, membranes, liquid crystals, biological materials and even liquid metals. The underlying issues concern not only the microstructure and dynamics, but also cooperative phenomena near phase transitions, hydrodynamic flow and instabilities.

Soft condensed matter is investigated principally by wide- and small-angle X-ray scattering techniques (WAXS/SAXS). These techniques are available at many beamlines, several of which are represented by highlights in this section. For the soft condensed matter community it is of particular importance that ID2 has been dedicated completely to SAXS during the year 2000. This gives more flexibility for the development of high Q-resolution and ultra small-angle scattering techniques (e.g. Bonse-Hart camera). Combined SAXS/WAXS techniques are now available on BM26 and are coming into operation on ID2.

The development of microfocus SAXS techniques has continued in particular on the beamlines ID13 and ID22 with beam sizes down to a few micrometres. Micro-SAXS has also been demonstrated on ID21 at 0.2 nm, which opens interesting perspectives for SAXS experiments in the soft spectral range.

In addition to these techniques, the development of X-ray correlation spectroscopy techniques (XPCS) continues on ID10, which is currently commissioning a SAXS camera with a coherent, pink beam. In the field of solid polymers/biopolymers, scattering experiments are being complemented more and more frequently by imaging experiments such as tomography (ID19, ID22) or X-ray microscopy techniques (ID21). This trend is expected to accelerate in the future. 

This year's highlights are dominated by experiments on samples at interfaces or in confined geometries. Thus lipid model membranes have been studied at solid surfaces by probing the nonspecular scattering (ID1). This is also of interest for the understanding of interfaces between biological and inorganic systems. The confinement of DNA in lipid membranes has led to the observation of a new liquid crystalline ordering (ID2). A new approach for studying ordering phenomena in confined fluids is provided by X-ray waveguide structures. It is well known that such devices can be used to produce completely coherent radiation, which propagates in several modes. In an experiment performed on ID10A, the waveguide is filled with a fluid and the influence on the mode propagation is observed in the far field regime. XPCS in grazing-incidence geometry has allowed the first study of capillary waves at a liquid glycerol surface by XPCS (ID10A). This geometry has also been used at high energies in order to observe an evanescent wave from a thin liquid layer close to a deeply buried interface. In this way, evidence for icosahedral fragments of lead atoms have been observed for the first time at the solid-liquid Si-Pb interface (ID15A).

The highlights also include several SAXS experiments from CRG beamlines. Thus liquid crystalline phase transitions in suspensions of Al(OH)3 platelets and the stability of a columnar phase were studied on BM26 down to Q2*10-2 nm-1. USAXS and XPCS experiments on filled polymers on BM2 remind us that such experiments are not reserved only for undulator beamlines.