Two-dimensional arrays of strings of TiO₂ nanoparticles via cooperative block copolymer self-assembly

An unprecedented path to synthesize 2D arrays of strings of titanium dioxide (TiO₂) nanoparticles was developed from cooperative self-assembly of poly(styrene-block-2-vinyl pyridine (Ps-b-P2VP) copolymer and titanium tetra-isopropoxide (TTIP)-based sol-gel precursors. Hybrid block copolymer (BCP)/titania thin films with nanohole and nanonetwork morphologies, depending on the relative composition of the mixed solution, were obtained by one-step spin coating of the mixed solution on silicon wafers. TiO₂ moieties merged form spherical nanoparticles where nanoholes were present at the center of individual nanoparticles. Experimental investigation suggested a rare scheme to induce 2D arrays of strings of TiO₂ nanoparticles based on cooperative BCP self-assembly that can be extended to obtain a wide range of inorganic nanostructures with tailored composition, size, and shape.