Introduction

The soft condensed matter highlights demonstrate the diversity of research being carried out at the soft condensed matter (ID02, ID10A/B and ID13) and several CRG beamlines. This diversity has promoted links to several neighbouring disciplines such as materials science, biology, and engineering.

Developments at beamline ID02 have included advances in time-resolved small- and wide-angle scattering (SAXS/WAXS) techniques. Weiss et al., have demonstrated SAXS combined with modelling at the millisecond scale for micellar self-assembly. This was achieved through the combination of stopped-flow techniques with a state-of-the art gas-filled detector. Close links to protein crystallography are evident in the experiments by Casselyn et al., who studied the onset of BMV virus crystallisation down to the critical nucleus. Also recently, Stribeck et al., have been able to determine the autocorrelation function during the onset of polyethylene crystallisation in real time. This allows the first steps of mesophase formation to be "visualised", which is of particular technological importance.

Ultra-small volumes and beam sizes are the realm of the microfocus beamline, ID13. Inkjet printing technology can deliver water droplets of 65 picoliters to precise locations without splashing. Lemke et al., have used this technique to study the onset of starch granule hydration by in situ WAXS. The observation of a fast volume hydration within a few seconds can be explained by the porous nature of this important biopolymer. Naturally, ID13 has also been closely involved in the development of nanobeams at the ESRF. The use of 100 nm beams is already current practice. The report by Loidl et al., demonstrates how such a beam can be used to study the strain field in a single carbon fibre across a bending zone.

The technique of X-ray photon correlation spectroscopy (XPCS) has been pioneered at ID10A. The highlight example concerns the study of ferrofluids containing core-shell particles. Robert et al., were able to extract the hydrodynamic function, which contains information on solvent-mediated interactions between the colloidal particles, from SAXS and XPCS data. The results challenge existing colloidal hydrodynamic theories, which cannot provide an adequate description of these interactions.

Grazing-incidence diffraction (GID) is the speciality of beamline ID10B. The X-ray optical system of ID10B allows in situ studies on liquid surfaces, for example in a Langmuir trough. Breiby et al., have studied the molecular ordering of poly(alkylthiophene) films on water. This also allowed them to study in situ doping by PF6-, which results in an insulating-conducting phase transition. In situ GID was also used by Berman et al., to study the nucleation of CdS and Ag2S nanocrystals at the air-solution interface.

The highlight that seems to have appealed the most to the general public has been the work carried out on chocolate by Peschar et al.. This is demonstrated by the unusually high number of mainstream press articles concerning this study. The work is being carried out at several CRG beamlines and involves wide- and small-angle scattering techniques. These results are being used to elucidate the complex phase behaviour of chocolate. The example reported below concerns the crystal structures of several cocoa butter triglycerides by powder diffraction on BM16 and BM01B.

C. Riekel