Nanoporous Redox-Active Miktoarm Block Copolymer Templates

A novel design strategy for versatile soft-etchable miktoarm block copolymers based on polystyrene (PS) and polylactide (PLA) in a three-arm star-like architecture is presented. Living anionic polymerization was employed for the PS block, followed by end functionalization with DL-1,2-isopropylidene glyceryl glycidyl ether (IGG), yielding PS with one hydroxyl group and two additional, protected OH groups at the omega-terminus. This synthetic route permits the selective substitution of the free hydroxyl group with an azide group, allowing for functionalization via click chemistry reactions. Well-defined AB(3) miktoarm block copolymers with three PLA arms and varying chain lengths were synthesized by the deprotection of the PS macroinitiator, followed by ring-opening polymerization of D,L-lactide. The morphologies of the underlying AB(3) miktoarm block copolymers were investigated in bulk and thin films. Cylinders oriented perpendicular to the substrate could be induced by solvent vapor annealing (SVA), resulting in highly ordered nanoporous templates after PLA soft-etching. The strategy was applied to poly(styrene-co-4-vinyltriphenylamine)-b-(PLA)(3), resulting in redox-active crosslinkable matrices, as demonstrated by means of cyclic voltammetry.