Tuning the Morphology of an Acrylate-Based Metallo-Supramolecular Network: From Vesicles to Cylinders

This work investigated the morphological behavior of an acrylate-based metallo-supramolecular polymer system. RAFT (reversible addition–fragmentation chain transfer) polymerization techniques were used to synthesize low molar mass, linear prepolymers of n-butyl acrylate and a 2,6-bis(1′-methylbenzimidazolyl)pyridine–acrylate monomer (MeBIP–Ac) of varying concentration (2–10%). This synthesis incorporated a systematic increase of cross-link points (MeBIP ligands) pendent to the polymer backbone. A zinc(II) salt (Zn(ClO4)2) complexed with the pendent MeBIP ligands in a 1:2 ratio to form cross-linked polymers as free-standing films. The morphology of the neat films as well as those with added unbound MeBIP–zinc–MeBIP metal–ligand (ML) complex were characterized using transmission electron microscopy (TEM), HAADF-STEM (high angle annular dark field scanning transmission electron microscopy), energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM), and ...