1 research outputs found
Guiding Block Copolymers into Sequenced Patterns via Inverted Terrace Formation
Corrugated SiCN ceramic substrates fabricated by a facile
replication
process using nonlithographic PDMS masters were employed for the directed
assembly of block copolymer microdomains. During thermal annealing
of polystyrene-<i>b</i>-polybutadiene diblock copolymer,
the material transport was guided by a wrinkled substrate to form
regular modulations in the film thickness. As a consequence of the
thickness-dependent morphological behavior of cylinder forming block
copolymer, the film surface appears as sequenced patterns of alternative
microphase-separated structures. The ordering process is attributed
to the formation of inverted terraces which match the substrate topography,
so that the resulting surface patterns are free from the surface relief
structures within macroscopically large areas. The issues of the film
thickness, the substrate surface energy, and the pattern geometry
are addressed. Our approach demonstrates an effective synergism of
external confinement and internal polymorphism of block copolymers
toward complex hierarchically structured patterned surfaces