Interpolyelectrolyte Complexes between Starlike and Linear Macromolecules: A Structural Model for Nonviral Gene Vectors

Molecular dynamics simulations are used to probe the structural organization of nonstoichiometric interpolyelectrolyte complexes (IPECs) formed by oppositely charged starlike and linear polyelectrolytes (PEs) in dilute aqueous solution. We demonstrate that undercompensated star-IPEC consists of a denser coacervate core and a charged starlike corona. Two distinctive populations of star branches-completely embedded in a coacervate core and stretched in a lyophilizing corona-are found. The scaling arguments support the stability of TPEC with partitioned star branches.