Self-assembly of polyelectrolyte diblock copolymers within mixtures of monovalent and multivalent counterions

• Published in: Physical chemistry chemical physics : PCCP 2020-07, Vol.22 (28), p.16334-16344
• Main Authors: Liu, Li-Yan, Yu, Zhong-Xun, Liu, Li-Xiang, Yang, Jing-Qi, Hao, Qing-Hai, Wei, Tong, Tan, Hong-Ge
• Format: Article
• Language: English
• Subjects: Block copolymers; Coronas; Face centered cubic lattice; Ion charge; Micelles; Molecular dynamics; Polyelectrolytes; Precipitates; Self-assembly; Trivalent ions
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d0cp01019g

In this study, the self-assembly behavior of polyelectrolyte (PE) diblock copolymers in solutions containing mixtures of monovalent and multivalent counterions was investigated using molecular dynamics simulation. The properties of the assembled micelles and counterion condensations at different charge fractions of multivalent ions have been discussed. The bridging effect of multivalent ions induces the electrostatic correlations of the PE chains, leading to the fusion of large micelles and the formation of bulky aggregates. Notably, lamellar and well-organized face-centered cubic (FCC) arrangements of the assembled micelles were observed in the mixture of monovalent and trivalent ions. At large fractions of multivalent ions, cylindrical and lamellar precipitates composed of the assembled micelles were formed owing to the inter-connecting coronas. The mixtures of monovalent and multivalent counterions allow the regulation of the electrostatic interactions and tuning of the properties in assembled micelles. Autocorrelation functions of radius of gyration of the PE chains in the mixtures of monovalent and trivalent, and monovalent and divalent ions are plotted in (a) and (b), respectively.