On the alignment of a cylindrical block copolymer: a time-resolved and 3-dimensional SFM study

Abstract

In a combined quasi in situscanning force microscopy study we close trace the alignment process of thin polymer films of poly(styrene)-b-poly(2-vinylpyridine)-b-poly(tert-butyl methacrylate) triblock terpolymer exposed to a high electric in-plane field and solvent vapor. Our experiments show that in this triblock terpolymer a perforated lamella structure forms the basis for the core–shell cylindrical structure. Further we observe a hexagonal superstructure during the alignment process that occurs with solvent vapor annealing in the presence of a high electric field (6–15 V μm⁻¹). The electric field induced reorientation includes a rupture-and-growth mechanism and the rotation of the hexagonal lattice. We reconstruct the 3D-structure of the aligned microdomains with quasi in situSFM nanotomography. The gained 3D reconstructions lead to a detailed understanding of the polymer film behavior in the border region between perforated lamella and the cylindrical phase. Combining time-resolved SFM datasets with 3D reconstructions, we present a model for the rearrangement of the polymer cylinders on the basis of a hexagonally perforated lamella. One-dimensionally aligned core–shell cylinders could form the basis for electrically isolated nanowires once the cylinder core is metalized.