1. Laboratoire de Sciences et Ingénierie de la Matière Molle; ESPCI Paristech-CNRS-UPMC; 10 rue Vauquelin, 75005 Paris France
2. Materials Research Laboratory; University of California Santa Barbara; California 93106
3. Department of Materials; University of California Santa Barbara; California 93106
4. Michelin; CERL Ladoux, F-63040 Clermont Ferrand; France
5. ESRF; 71, Avenue des Martyrs; 38043 Grenoble Cedex 9 France
6. Department of Chemical Engineering; University of California Santa Barbara; California 83106