1. Polymer Science and Engineering Department University of Massachusetts Amherst 120 Governors Drive Amherst MA 01003 USA
2. Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
3. Materials Sciences Division Lawrence Berkeley National Lab 1 Cyclotron Road Berkeley CA 94720 USA
4. Stanford Synchrotron Radiation Light Source SLAC National Accelerator Laboratory Menlo Park CA 94025 USA