Self assembly of polystyrene-block-poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) (SVT) triblock copolymers in bulk and in thin films

摘要

We have recently reported on first experiments investigating the thin film behavior of ABC triblock copolymers. In the presence of boundary surfaces and confinement to thicknesses comparable to the characteristic bulk spacing, the microdomain structures of block copolymers can significantly differ from the respective bulk structures. Both large scale alignment of the microdomains as well as the formation of novel microdomain structures has been observed. For the particular case of a polystyrene-block-poly(2-vinyl pyridine)-block-poly(tert-butyl methacrylate) (SVT) triblock copolymer with volume fractions φ:φ:φ scaling as 1:1.4:3 a particularly rich variety of thin film structures was recently found. In order to be able to study these phenomena more systematically, we have synthesized two series of triblock copolymers which xhibit a certain constant ratio between the PS and P2VP blocks, while the volume fraction of the PtBMA block was increased stepwise within each series. The goal of this procedure is to systematically explore certain regions of the ternary phase diagram. Here, we summarize our synthetic results and describe the structures found for the various materials as a function of composition.