Titanium particle incorporation in block copolymer templates

• A systematic study of titanium formation on and inside PS-b-PEO block copolymer templates is presented.
• Titanium decorates preferentially the PS block of the templates.
• Titanium penetrates into the BCP film, reproducing the BCP template morphology.

Template-directed formation of titanium structures on block copolymer templates has been recently reported [1]. Here, the incorporation of titanium in a thin film template is studied. We show that the surface free energy contrast in microphase-separated polystyrene-block-polyethylene oxide templates is not limited to the template film surface, but directs the assembly of titanium atoms in the template thin film. The details of the self-assembly of titanium particles on the block copolymer nanostructured surface and inside the 3D film structure are studied with selected amounts of titanium. Evaporated titanium preferentially wets the polystyrene block of the block copolymer film and diffuses inside the film, conserving the block copolymer nanostructure. Increasing deposition leads to the formation of a mesoporous titanium layer on the block copolymer film, which reproduces that of the underlying template, in this particular case with a thickness of 12 nm and a periodic pore-to-pore distance of 35 nm. The formation of a mesoporous titanium layer prevents from further titanium diffusion inside the block copolymer film. The combination of the X-ray scattering techniques presented here provides sufficient sensitivity to follow the titanium formation in the three dimensional network of the block copolymer films.

Figure optionsDownload high-quality image (366 K)Download as PowerPoint slide