Archimedean Tilings and Hierarchical Lamellar Morphology Formed by Semicrystalline Miktoarm Star Terpolymer Thin Films
Abstract
3-Miktoarm star terpolymer architecture provides a window of opportunity in the design of complex "three-colored" patterns at the nanometer scale. Here, the directed self-assembly (DSA) of 3-miktoarm star terpolymer (poly(1, 1-dimethyl silacydobutane)-arm-polystyrene-armpoly(D,L-lactide acid)) (PDMSB-arm-PS-arm-PLA, noted hereafter 3 mu-DSL) into a hierarchical lamellar morphology is described. Excellent orientational order has been achieved by templating the asymmetric hierarchical lamellar morphology with topographical substrates. Increasing the PLA volume fraction leads to the formation of a hexagonal [6.6.6] Archimedean tiling which coexists with a metastable square symmetry [4.8.8] tiling stabilized by the step between terraces. Stability of the [6.6.6] tiling over the [4.8.8] one is also demonstrated with GISAXS measurements.