1. Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, Department of Biophysics E22, Technical University of Munich, D-85748 Garching, Germany, Forschungszentrum Jülich, Institut für Schichten und Grenzflächen (ISG-4), D-52425 Jülich, Germany, and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139