Topological Effects on Cyclic Co‐Poly(ionic liquid)s Self‐Assembly

Abstract

AbstractTopological geometry of poly(ionic liquid)s (PILs), such as brush‐like, knot‐like, hyperbranched and randomly coiled, often exerts a strong influence on their self‐assembly behaviors. As a primary topological form, the cyclic topology‐derived effects have not been investigated on PILs, which concerns synergy of charges and zero chain end. Herein, linear and cyclic poly(ionic liquid) copolymers (co‐PILs) with randomly distributed counter anions of B(Ph)4− and Br− by a template method in combination with a follow‐up partial anion exchange is prepared. The self‐assembly phenomena of linear and cyclic co‐PILs are studied in selective solvents, where the hydrophobic counter anions B(Ph)4− and hydrophilic counter anions Br− aggregated to form cores and corona in the assembled nanospheres, showing the average size of cyclic co‐PILs nanospheres is 46.2% smaller (≈120 nm) than linear co‐PILs nano‐assemblies (≈176 nm). Based on the CGMD simulations, the authors speculate that the spherical aggregates are formed by transitioning from micelles with gradient block‐like structures, which formed by enriched hydrophobic counter anions in the core and enriched hydrophilic counter anions in the corona. These results indicate a novel synergy of topology effects and dynamic anion movements, as revealed by cyclic co‐PIL self‐assembly in this work.