Formation of Supramolecular Polymer Network and Single-Chain Polymer Nanoparticles via Host–Guest Complexation from Pillar[5]arene Pendant Polymer

A pillar[5]arene pendant polymer was synthesized by ring-opening metathesis polymerization using the Grubbs first-generation catalyst and cross-linked using a bis(imidazolium) cross-linker via host–guest complexation. Inclusion of the bis(imidazolium) guest within the cavity of the pillar[5]arene resulted in the formation of a supramolecular polymer network (SPN) at high concentration. Upon high dilution, the SPN formed single-chain polymer nanoparticles (SCPNs). The formation of the SPN and SCPNs were evidenced by NMR spectroscopy, dynamic light scattering, scanning electron microscopy, and atomic force microscopy.