Supramolecular Assembly of Poly(styrene)-b-poly(4-vinylpyridine) and 1-Pyrenebutyric Acid in Thin Film and Their Use for Nanofabrication

Supramolecular assembly (SMA) between poly(styrene)-b-poly(4-vinylpyridine) (PS-b-P4VP) and 1-pyrenebutyric acid (PBA) is investigated in thin films after annealing in a 1,4-dioxane atmosphere. The PBA selectively enriches with the P4VP block through hydrogen bonding between the carboxylic group of 1-pyrenebutyric acid and pyridine ring of P4VP. The supramolecular assembly of PS-b-P4VP with 1-pyrenebutyric acid resulted in changing the cylindrical morphology of pure block copolymer into lamellar morphology in thin film due to the increase of the block compositions of P4VP (PBA). Pure block copolymer after solvent annealing shows cylindrical microdomains normal to the substrate with a periodicity similar to 26 nm, whereas the SMA complex shows perpendicularly oriented lamella with a periodicity similar to 29 nm. These thin films were further immersed in ethanol, a good solvent for P4VP/P4VP (PBA) and a nonsolvent for PS to generate nanotemplates. These nanotemplates are effectively used for the fabrication of arrays of nanowires of different functional materials like metal or semiconductor.