Various types of devices require hierarchically nanopatterned substrates, where the spacing between patterned domains is controlled. Ultraconfined films exhibit extreme morphological sensitivity to slight variations in film thickness when the substrate is highly selective toward one of the blocks. Here, it is shown that using the substrate's topography as a thickness differentiating tool enables the creation of domains with different surface patterns in a fully controlled fashion from a single, unblended block copolymer. This approach is applicable to block copolymers of different compositions and to different topographical patterns and thus opens numerous possibilities for the hierarchical construction of multifunctional devices.
Bibliographical noteFunding Information:
We thank Rabibrata Mukherjee for stimulating discussions. We thank Evgenia Blayvas for assistance with the XHR SEM imaging. E.M. thanks the Cambr Charitable Foundation for a Ph.D. fellowship.
This research was supported by the Israel Science Foundation (grant number 229/17) and the Deutsche Forschungsgemeinschaft (grant SFB 1073/TPA03).
© 2019 American Chemical Society.
- block copolymer
- directed self-assembly
- thin film