1. Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
2. Swiss Light Source, Paul Scherrer Institut, 5232 Villigen, Switzerland
3. Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, 41125 Modena, Italy
4. Physics Dept, University of Modena and Reggio Emilia, 41125 Modena, Italy
5. Max Planck Institut for Polymer Research, 55128 Mainz, Germany