Suppression of Supramolecular Disassembly of Pseudopolyrotaxane Nanosheet by End-Capping via Amine–Epoxy Click Reaction of Bifunctional Epoxy

Abstract

Topological supramolecules have a unique structure with interlocking components. For polyrotaxane and pseudopolyrotaxane structures, the rings pass the axis' ends when they disassemble. In this study, the disassembly behavior of a pseudopolyrotaxane nanosheet (PPRNS), a topological supramolecular material consisting of β-cyclodextrin (CD) and linear triblock copolymer, was controlled by modifying the axis ends. Ethylene glycol diglycidyl ether (EGDGE), an abundant and inexpensive bifunctional epoxy reagent, was used to modify the amine-modified axis ends in water at room temperature. After the reaction, the branched chain of the tertiary amine, which was reacted by two EGDGE, acted as a capping and inhibited PPRNS disassembly, while the bridging structure was less effective in inhibiting disassembly. The disassembly behavior of the β-CD crystal layer was controlled by the structure of axis ends, which are located far from the β-CD crystal layer. This strategy to control topological supramolecular disassembly provides a new perspective for designing material properties.