Perpendicular Alignment and Selective Swelling-Induced Generation of Homopores of Polystyrene- b-poly(2-vinylpyridine)- b-poly(ethylene oxide) Triblock Terpolymer

Arrays of perpendicularly ordered nanopores with pore walls decorated by two or more functional polymer chains are of great importance in various applications. However, such porous structures have been rarely reported so far. Herein, lamellar-forming triblock terpolymer of polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) is blended with PS homopolymers to fabricate a PS matrix embedded with perpendicular PEO@P2VP cylinders via solvent annealing. By further adjusting the annealing humidity and temperature, the perpendicular PEO@P2VP cylinders are capable of running through the entire films. The hydrophilic PEO@P2VP domains could be converted into cylindrical homopores by ethanol swelling, where the functional P2VP and PEO chains are distributed on the pore walls. Moreover, water is able to swell PEO and also produces homopores in such films. The pore sizes of the films are readily tuned in a relatively large range depending on the swelling temperatures and durations. The developed ordered nanostructures are expected to find important applications in the range from template synthesis to membrane separation and to nanofluidics.