1. Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
2. Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, The Netherlands
3. Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany