1. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290; Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia; Department of Chemistry, University of Athens, Panepistimiopolis, Zografou, 157 71 Athens, Greece; and Institut de Chimie des Surfaces et Interfaces, CNRS UPR 9069, 15 rue Jean Starcky, 68057 Mulhouse, France