Nanoscale Archimedean Tilings Formed by 3-Miktoarm Star Terpolymer Thin Films.

ABSTRACT

3-Miktoarm star terpolymer architecture (3µ-ABC), consisting of three dissimilar polymer chains, A, B, and C connected at a junction point, provides a unique opportunity in the design of complex nanoscale patterns such as Archimedean tilings that are not accessible from linear ABC terpolymers. In this work, the synthesis and the self-assembly of 3-miktoarm star terpolymers, namely, polystyrene-arm-poly(2-vinylpyridine)-arm-polyisoprene (3µ-SPI) into Archimedean tiling patterns is described. Several 3µ-SPI terpolymers are produced via a mid-functional PS-b-P2VP, synthesized by sequential anionic polymerization, using a 1,1-diphenylethylene bearing a tert-butyldimethylsilyl-protected hydroxyl functionality as a core molecule. PI arms with different sizes are then linked to the deprotected hydroxyl function of the core molecule via a Steglich esterification. Solvent-annealed 3µ-SPI thin films exhibit nanoscale prisms arranged into a (4.6.12) Archimedean tiling pattern. Depending on the size of the low etch-resistant PI arm and the solvent selected to promote the self-assembly of 3µ-SPI thin films, the voided columns occupy the square or decagonal sites of the (4.6.12) pattern. The use of this (4.6.12) tiling produced for the first time from self-assembled 3µ-ABC thin films can be a promising route to build 2D photonic crystals having complete photonic band gaps, where the light propagation is completely prohibited.