Nanoscale Patterning of Barium Titanate on Block Copolymers

Atriblock copolymerof polystyrene-polybutadiene-polystyrene (KratonD1102)hasbeenused topattern barium titanate precursor with nanoscale modulations. The copolymer self-assembles to yield cylindrical polystyrene nanodomains in a polybutadiene matrix. The preorganized thin films of polymer are then selectively OH-functionalized in situ on the unsaturated carbon bonds in the polybutadiene matrix with antistereochemistry. Anchoring the barium titanate precursor onto the hydroxylated polymer thin films is possible only in the trans-1,2 polybutadiolmatrix through the condensationbetween the bariumtitanium double alkoxides and the hydroxyl groups. The regioselective deposition of the barium titanium double alkoxides on the original polybutadiene matrix of the Kraton thin films was verified by transmission electronmicroscopyand electron energy loss spectroscopy. The spacing of the coordinated bariumtitanium double alkoxide pattern was∼23 nm, equivalent to the interdomain spacing of the original polybutadiene matrix.