Controlling the Non-Conventional Self-Assembly of Charged Block Copolymer Thin Films

The self-assembly of block copolymer (BCP) in thin films has attracted great attention as a potential platform for next-generation nanofabrication. For the advancement of future BCP nanopatterning, it is essential to develop nanostructures that go beyond the conventional morphologies (i.e., lamella, cylinder, sphere) of BCPs. To achieve this, various approaches—such as polymer blending, confinement, and the application of external fields—have been proposed. Despite such efforts, the accessible range of nanopatterns remains limited.

In this study, we expand the nanopattern library of BCPs by selectively charging one block. block. Specifically, the core of polystyrene-b-poly(2-vinylpyridine) cylinders is charged through immersion in anionic metal complex solutions, followed by thermal annealing, which induces a transition into unique non-conventional morphologies. Image analysis reveals that the transition pathway is governed by the defectivity of the initial cylinders, thereby determining the resulting structure. We further discuss the industrial applicability of non-conventional nanopatterns and propose charging as a facile strategy for fabricating new nanostructures that are inaccessible through conventional BCP self-assembly.