1. Laboratoire Chimie de la Matière Condensée de Paris, UMR 7574 CNRS, UPMC, EPHE, Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
2. Laboratoire Physique des Solides, UMR 8502 CNRS, Université Paris Sud XI, Orsay 91405 Cedex, France
3. Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, 14424 Potsdam, Germany
4. European Synchrotron Radiation Facility, High Brilliance Beamline ID2, BP 220, 38043 Grenoble Cedex, France