[1] Univ Massachusetts, Dept Polymer Sci & Engn, Conte Res Ctr, Amherst, MA 01003 USA
[2] Univ Calif Santa Barbara, Dept Mat, Ctr Polymers & Organ Solids, Dept Chem & Biochem, Santa Barbara, CA 93106 USA
[3] Stanford Synchrotron Radiat Lightsource, Menlo Pk, CA 94025 USA