* Corresponding authors

^a Conte Center for Polymer Research, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
E-mail: watkins@polysci.umass.edu

^b Department of Chemical and Biomolecular Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
E-mail: nianqiangwu@umass.edu

^c Department of Physics, Tamkang University, Tamsui, Taiwan

^d Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052, Australia

^e National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

^f School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia