Supramolecular assemblies with tunable morphologies from homopolymeric and small organic molecular building blocks

This work demonstrates the formation of micrometer-sized supramolecular assemblies with tunable morphologies using a homopolymer, poly( 4-vinylpyridine), and a small organic acid, 5,7-dodecadiynedioic acid, as the building molecules. Three different morphologies ( hollow spheres, solid spheres, and rods) were obtained, depending on the molar ratio of the building molecules. It is proposed that hydrogen bonding between P4VP and DCDA and the pi-pi stacking of the diacetylenic moieties are responsible for the formation of these assemblies. Interestingly, ordered hexagonal and lamellar mesostructures were also formed within the microstructure during the co-assembly process. As a result, UV irradiation of the supramolecular assemblies polymerized the diacetylenic moieties, resulting in cross-linked and responsive blue polydiacetylenic assemblies that can change color to red upon external stimuli ( e. g., thermal stimuli). This work provides a novel concept of the synthesis of responsive supramolecular assemblies from a homopolymer and small organic molecules.