A new process for fabricating nanodot arrays on selective regions with diblock copolymer thin film

A procedure for micropatterning a single layer of nanodot arrays in selective regions is demonstrated by using thin films of polystyrene- b -poly( t -butyl acrylate) (PS- b- P t BA) diblock copolymer. The thin-film self-assembled into hexagonally arranged P t BA nanodomains in a PS matrix on a substrate by solvent annealing with 1,4-dioxane. The P t BA nanodomains were converted into poly(acrylic acid) (PAA) having carboxylic-acid-functionalized nanodomains by exposure to hydrochloric acid vapor, or were removed by ultraviolet (UV) irradiation to generate vacant sites without any functional groups due to the elimination of P t BA domains. By sequential treatment with aqueous sodium bicarbonate and aqueous zinc acetate solution, zinc cations were selectively loaded only on the carboxylic-acid-functionalized nanodomains prepared via hydrolysis. Macroscopic patterning through a photomask via UV irradiation, hydrolysis, sequential zinc cation loading and calcination left a nanodot array of zinc oxide on a selectively UV-shaded region.