1. Departments of Chemistry and Materials Science, University of Crete and Technology and FORTH, 71110 Heraklion, Greece; Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213; Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213; and Max Planck Institute for Polymer Research, Ackermannsweg 10, 55128 Mainz, Germany