Onion Micelles with an Interpolyelectrolyte Complex Middle Layer: Experimental Motivation and Computer Study
Abstract
The paper describes the successful preparation of onion micelles by sequential combination of self-assembly of amphiphilic polyelectrolytes (PEs) in aqueous media and electrostatic coassembly of core-shell micelles formed in the first step with the oppositely charged double-hydrophilic copolymer. Experimental study and computer modeling (dissipative particle dynamics with explicit electrostatics) aimed at important features and trends of the assembly process were motivated by the controversy between the ease of the process deduced from thermodynamic considerations and the low number of successful literature reports.
The results show that onion micelles can be prepared if the studied system fulfills certain thermodynamic criteria and avoids kinetic obstacles. Nevertheless, the formation of well-developed onion micelles requires some hydrophobicity of PE backbones and their incompatibility with the soluble block.
Otherwise, irregular low-density gel-like associates are formed. The increase in PE hydrophobicity and incompatibility promotes the assembly and improves the uniformity and spherical shape of onion micelles.