1. Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180, National Synchrotron Light Source, Brookhaven National Laboratory (BNL), Upton, New York 11973, Department of Chemical Engineering, Stanford University, Stanford, California 94305, and Material Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180