Ordered nanoassemblies from self-assembly of amphiphilic molecule containing pillar[5]arene and azobenzene groups

Abstract

The derivatization of pillar[n]arenes is a prerequisite for endowing them with functions, as well as enriching the application of pillar[n]arene materials in advanced material science. Herein, we report the self-assembly of amphiphilic rim-differentiated pillar[5]arene (H₁). One side of the pillar[5]arene is composed of hydrophilic poly(ethylene oxide) chains, benzene and azobenzene groups connected with ether bonds, and the other side is composed of ethoxy groups. In CHCl₃ solvent, the amphiphile H₁ self-assembled into spherical micelles, while in H₂O/THF mixed solvent H₁ self-assembled into nanorod-like assemblies. Interestingly, addition of a guest molecule composed of tetraphenylethene and hexanenitrile groups (G₁) to the CHCl₃ solution of H₁ produces large sheet aggregates via the strong π–π stacking of rod segments. The reversible transformation between the nanosheet assemblies of host–guest complexes and nanoparticles is achieved by addition of the guest molecule 1,4-butylamine (G₂) and pillar[5]arene with ethoxy groups as competitive molecules. Notably, worm-like and nanorod micelles of H₁ were constructed in H₂O/THF solution triggered by light irradiation, which assemblies can be used as photosensitive erasable writing materials. © 2023 Society of Industrial Chemistry.