1. Department of Physical and Analytical Chemistry, Uppsala University, Box 579 SE-751 23 Uppsala, Sweden
2. GKSS Research Centre, Max-Planck-Strasse, 21502 Geesthacht, Germany
3. Division of Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University, SE-41296 Göteborg, Sweden
4. Equipe Physico-chimie des Colloïdes, UMR SRSMC No. 7565 CNRS/Nancy Université, F-54506 Vandoeuvre-les-Nancy, cedex, France