This work was supported by the US Department of Defense, Army Research Office, under contract W911NF-13-1-0232 and the National Science Foundation under contract DMR-183696. M.O.d.l.C. and B.Q. acknowledge support through grant DE-FG02-08ER46539 from the Department of Energy (DOE) Basic Energy Science Office and the Center for Computation and Theory of Soft Materials, as well as computational support by the Sherman Fairchild Foundation. Z. H. and M. R. acknowledge support from the Air Force Office of Sponsored Research Award FA9550-15-1-0273. A part of this research used resources at the High Flux Isotope Laboratory, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We acknowledge the support of the National Institute of Standards and Technology, US Department of Commerce, in providing the neutron research facilities used in this work. We thank L. He and Y. Liu for help in the SANS studies. Scattering studies at the Advanced Light Source and RHP characterization at the Molecular Foundry were supported by the Office of Science, Office of Basic Energy Sciences of the US DOE under contract DE-AC02-05CH11231. We thank A. A. A. Smith for help in polymer syntheses; Y. W. Qian for characterizing the liposome sizes; A. Martin and E. M. López-Alfonzo for help in stopped-flow experiments. We thank CoC-NMR for help with RHP characterization; instruments at CoC-NMR are supported in part by NIH S10OD024998.