C.A.M. acknowledges the following awards for support of this work: AFOSR FA9550-09-1-0294, FA9550-11-1-0275 and FA9550-12-1-0280, DoD/NSSEFF/NPS N00244-09-1-0012 and N00244-09-1-0071, NSF MRSEC DMR-1121262, and the DoE/Office of Science/Office of Basic Energy Sciences NERC DE-SC0000989. M.R.J. is grateful to the NSF for a Graduate Research Fellowship and to Northwestern University for a Ryan Fellowship. Small-angle X-ray scattering was carried out at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) beamline located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by E. I. DuPont de Nemours & Co., The Dow Chemical Company, and the State of Illinois. Use of the APS was supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The ICP-AES analysis was completed at the Northwestern University Integrated Molecular Structure Education and Research Center (IMSERC).