Directed Assembly of Cylinder-Forming Block Copolymer Films and Thermochemically Induced Cylinder to Sphere Transition: A Hierarchical Route to Linear Arrays of Nanodots

Abstract

A morphological transition from cylinders to spheres was induced in an asymmetric diblock copolymer, poly(styrene)-block-poly(tert-butyl acrylate) (PS-b-PtBA). The periodic arrays of the poly(tert-butyl acrylate) (PtBA) domains were transformed to the ordered poly(acrylic anhydride) (PAA) spheres via the thermal deprotection of tert-butyl acrylate linkages and the subsequent volume change of the minority block. Coupled with techniques to direct the assembly of cylinder-forming block copolymers, this finding provides new routes to fabricate ordered geometries of nanodot arrays.