Onion Micelles with an Interpolyelectrolyte Complex Middle Layer: Experimental Motivation and Computer Study

Abstract

The paper describes successful preparation of onion micelles by sequential combination of self-assembly of amphiphilic polyelectrolytes (PE) in aqueous media and electrostatic coassembly of core/shell micelles formed in the first step with the oppositely charged doublehydrophilic 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 easiness 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 fulfils 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.

DPD Modelling of the Self- and Co-Assembly of Polymers and Polyelectrolytes in Aqueous Media: Impact on Polymer Science

“…An interesting DPD study of the complex process comprising the combination of electrostatic co-assembly and amphiphilic self-assembly was recently published by a team of experimentalists and computer scientists. They studied the formation and properties of onion micelles prepared by mixing preformed core-shell micelles composed of hydrophobic cores and cationic polyelectrolyte shells with a double-hydrophilic block copolymer composed of an anionic block and a water-soluble poly(ethylene oxide) block [235]. The simulation proved that the three-layer micelles with the compact central hydrophobic block, compact middle interpolyelectrolyte complex layer and the diffuse stabilizing water-soluble shell form not only in mixtures of pre-aggregated core-shell micelles, but also upon the transfer of the components dissolved in a common solvent into a selective aqueous medium.…”

100th Anniversary of Macromolecular Science Viewpoint: Attractive Soft Matter: Association Kinetics, Dynamics, and Pathway Complexity in Electrostatically Coassembled Micelles

“…The use of various types of (partially) immiscible components creates multicompartment micelles comprising mixed cores and demixed shells 99 or, vice versa, demixed cores and mixed shells. 6 As a result of demixing of the components, one can obtain Janus micelles, 100 core–shell–corona micelles (i.e., onion-like micelles), 74 , 101 − 103 and patchy micelles. 104 …”

Core–Satellite Micelles by a Linear A1B1A2B2 Tetrablock Copolymer

“…Also, various micellar morphologies, for example, worm-like, cylindrical, or vesicle micelles, − have been observed by changing the inherent curvature of the molecule, which can influence the packing of the block copolymer chains in a solvent. Block copolymer micelles have been extensively investigated because of a variety of applications. − To expand these applications, more complex nanostructures of block copolymer micelles have been suggested. − For example, multicompartment micelles such as hamburger micelles or worm-like micelles were observed by using poly­(ethylene oxide)- block -polyethylethylene- block -poly­(perfluoropropyleneoxide) miktoarm star block copolymers . Controlled patchy micelles were observed in linear polystyrene- block -polybutadiene- block -poly­( tert -butyl methacrylate) triblock terpolymers .…”