As in the previous years, this section comprises a selection of highlights that is a sub-set of many interesting scientific results published over the year. Contributions are included from both the public beamlines in the Structure of Soft Matter group and the CRG beamlines. One of the striking features of this year’s articles is the strong emphasis on the complementary techniques and implications of modelling and simulations. Many of these contributions are not standalone examples and scattering results are interpreted with the aid of complementary techniques. A positive aspect is the use of advanced computer simulations to extract quantitative details. Evidently, there is strong overlap with other disciplines such as materials and biological sciences.

The arrested states in soft matter systems continue to attract renewed interest. In the first article, Ruzicka et al. present evidence for the Wigner glass state in Laponite clay suspensions by a combination of SAXS experiments, theory and computer simulation. The second article, by László et al., identifies the jammed dynamics in PNIPA gel using XPCS and relates the microscopic relaxation rate to the macroscopic deswelling ratio. The third article, by Poulos et al., reports the scale-dependent dynamics of the nematic phase of goethite suspensions by means of XPCS and poses the difficult question on the crossover from the microscopic particulate dynamics to the macroscopic continuum hydrodynamics.

Proteins and other biomolecules at interfaces continue to be the focus of research using surface and interface sensitive techniques. The article by Singh et al. reveals the different steps in lysozyme adsorption at the air-water interface. Schneck et al. explain the crucial role played by charged saccharides in the survival of bacteria against antimicrobial peptides.

Accardo et al. present an interesting technical development suitable for near contact-free manipulation of protein (lysozyme) droplets using ultra-hydrophobic surfaces. Knaapila et al. report on the microstructure of an aligned polymer blend (polyfluorene in polyethylene) and the relationship with the photoluminescence property of the blend. Past Highlights issues have seen articles on the dynamics of the self-assembly process of surfactants, block copolymers, peptides, etc. Here, Besenius et al. demonstrate the directional self-assembly of chiral supramolecular polymers in water to form elongated rod-like assemblies.

Time-resolved pump-probe solution X-ray scattering continues to shed new light on the chemical reaction pathways. Kong et al. demonstrate two different pathways in the photolysis of Ru3(CO)12 in cyclohexane depending on the photexcitation energy or its proximity to the electronic absorption bands. Finally, the article by Okemefuna et al. illustrates the usefulness of solution SAXS in the structural elucidation of highly flexible proteins such as complement factor H which are not amenable to crystallographic studies.

The past year also saw some apprehensions within the Soft Matter user community regarding the status of the newly established Partnership for Soft Condensed Matter and the ID10 A and B beamlines. This situation was a consequence of the difficult budgetary situation imposed on the ESRF. Finally, it has been decided by the ESRF management to combine the XPCS and liquid surface and interface scattering activities at ID10 A and B, respectively into one beamline with two stations operating alternately. To facilitate this change, a major refurbishment of the ID10 beamline complex is foreseen. This will allow us to enhance the performance of both XPCS and surface and interface scattering techniques significantly, though the total available beam time will be halved. Among the other major technical developments, the ID13 nano-endstation has become fully operational. ID09B has successfully commissioned a state-of-the-art picosecond laser system and multilayer X-ray optics. The technical design for UPBL9a, the extension of ID02 to an ultra high resolution small-angle scattering beamline, is underway.   

T. Narayanan