1. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, Zernike Institute for Advanced Materials, Department of Polymer Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany, and Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210