@article{3921,
  abstract     = {{Bottom-up patterning techniques allow for the creation of surfaces with ordered arrays of nanoscale features
on large areas. Two bottom-up techniques suitable for the formation of regular nanopatterns on
different length scales are nanosphere lithography (NSL) and block copolymer (BCP) lithography. In this
paper it is shown that NSL and BCP lithography can be combined to easily design hierarchically nanopatterned
surfaces of different materials. Nanosphere lithography is used for the pre-patterning of
surfaces with antidots, i.e. hexagonally arranged cylindrical holes in thin films of Au, Pt and TiO2 on SiO2,
providing a periodic chemical and topographical contrast on the surface suitable for templating in subsequent
BCP lithography. PS-b-PMMA BCP is used in the second self-assembly step to form hexagonally
arranged nanopores with sub-20 nm diameter within the antidots upon microphase separation. To
achieve this the microphase separation of BCP on planar surfaces is studied, too, and it is demonstrated
for the first time that vertical BCP nanopores can be formed on TiO2, Au and Pt films without using any
neutralization layers. To explain this the influence of surface energy, polarity and roughness on the microphase
separation is investigated and discussed along with the wetting state of BCP on NSL-pre-patterned
surfaces. The presented novel route for the creation of advanced hierarchical nanopatterns is easily applicable
on large-area surfaces of different materials. This flexibility makes it suitable for a broad range of
applications, from the morphological design of biocompatible surfaces for life science to complex
pre-patterns for nanoparticle placement in semiconductor technology.}},
  author       = {{Brassat, Katharina and Kool, Daniel and Bürger, Julius and Lindner, Jörg}},
  issn         = {{2040-3364}},
  journal      = {{Nanoscale}},
  number       = {{21}},
  pages        = {{10005--10017}},
  publisher    = {{Royal Society of Chemistry (RSC)}},
  title        = {{{Hierarchical nanopores formed by block copolymer lithography on the surfaces of different materials pre-patterned by nanosphere lithography}}},
  doi          = {{10.1039/c8nr01397g}},
  volume       = {{10}},
  year         = {{2018}},
}