1. Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 7251 CNRS, Campus de Luminy, 13288 Marseille Cedex 09, France