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Chaotropic‐Anion‐Induced Supramolecular Self‐Assembly of Ionic Polymeric Micelles
Author(s) -
Li Yang,
Wang Yiguang,
Huang Gang,
Ma Xinpeng,
Zhou Kejin,
Gao Jinming
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201402525
Subject(s) - chaotropic agent , micelle , chemistry , amphiphile , non covalent interactions , supramolecular chemistry , critical micelle concentration , hydrophobic effect , self assembly , van der waals force , aggregation number , ionic bonding , molecule , ion , polymer chemistry , organic chemistry , copolymer , aqueous solution , hydrogen bond , polymer
Traditional micelle self‐assembly is driven by the association of hydrophobic segments of amphiphilic molecules forming distinctive core–shell nanostructures in water. Here we report a surprising chaotropic‐anion‐induced micellization of cationic ammonium‐containing block copolymers. The resulting micelle nanoparticle consists of a large number of ion pairs (≈60 000) in each hydrophobic core. Unlike chaotropic anions (e.g. ClO 4 − ), kosmotropic anions (e.g. SO 4 2− ) were not able to induce micelle formation. A positive cooperativity was observed during micellization, for which only a three‐fold increase in ClO 4 − concentration was necessary for micelle formation, similar to our previously reported ultra‐pH‐responsive behavior. This unique ion‐pair‐containing micelle provides a useful model system to study the complex interplay of noncovalent interactions (e.g. electrostatic, van der Waals, and hydrophobic forces) during micelle self‐assembly.