Double-layered micellar interpolyelectrolyte complexes—how many shells to a core?

Abstract

We report on the formation of double-layered micellar interpolyelectrolyte complexes (IPECs) from ABC triblock terpolymer precursor micelles and hydrophilic homo- or block copolymers. Polybutadiene-block-poly(1-methyl-2-vinyl pyridinium)-block-poly(sodium methacrylate) (PB-b-P2VPq-b-PMANa) block terpolymers form micelles in aqueous solution at high pH exhibiting a PB core, a P2VPq/PMANa intramicellar IPEC (im-IPEC) shell, and a PMANa corona, which is negatively charged. Upon mixing with either positively charged, quaternized poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMAq) homopolymers or its double-hydrophilic block copolymer with poly(ethylene oxide) (PEO-b-PDMAEMAq), a further IPEC shell is formed, rendering core–shell–shell–corona aggregates. The effects of the ratio of positive to negative charges, Z_+/−, the composition of the block terpolymer micelles, and the length of the added Dq block were investigated. We show that within a certain Z_+/− regime stable complex micellar IPECs featuring two distinguishable IPEC shells are formed. The so-formed complex particles were analyzed by dynamic light scattering and cryogenic transmission electron microscopy.