Nanopatterning of 2D materials by block copolymer self-assembly

As we face emerging global challenges, such as rising energy consumption and drinking water scarcity it is necessary that we invest in the research and development of new technologies. Nanopatterning using block copolymer (BCP) self-assembly is a promising way to advancements in applications ranging from water treatment technologies to energy-efficient devices. 2D materials have also shown great potential for many future technologies, including the aforementioned.

Nano-structuring of 2D materials is key to tuning their properties, for example introducing a bandgap in graphene via a nanomesh or nanoribbons. This requires high-quality periodic patterns with nanoscale resolution over large areas. Most conventional nanostructuring techniques for 2D materials are difficult to scale. BCP nanopatterning can offer a scalable solution, but few studies show this technique applied to 2D materials beyond graphene. Different surface interactions on various 2D materials can have a determining role in BCP microphase segregation. In this PhD thesis, the anionic polymerization of cylindrical forming polystyrene-block-polydimethylsiloxane, (PS-b-PDMS) is reported and for the first time, the characterization and direct confirmation of its formation are done through a fast multidimensional ¹H-²⁹Si HMBC NMR experiment. Furthermore, the self-assembly of cylindrical forming PS-b-PDMS on mechanically exfoliated hexagonal boron nitride (hBN) is investigated and used for the nanopatterning of hBN and an hBN encapsulated graphene van der Waals (vdW) heterostructure.

The use of soft topographic guiding patterns for the directed self-assembly (DSA) of cylindrical forming PS-b-PDMS is also being studied on top of 2D materials. The main goal with this is to achieve ordered PDMS nanochannels that can be encapsulated between 2D materials for the fabrication of a nanofluidic device.

The discoveries presented in this thesis aim to uncover the immense potential of BCP nanopatterning in conjunction with 2D materials and to inspire further exploration of this exciting research area.