Morphology Evolution of Block Copolymer Blend Thin Films Induced by Solvent Vapor Annealing. Issue 1 (2nd January 2021) - Cong, Yang
ABSTRACT: Self-assembly of binary block copolymer blends in thin film induced by solvent vapor annealing has been systematically studied. The diblock copolymers polystyrene-b-poly(2-vinylpyridine) with different molecular weights and volume fractions were blended with different molar ratios to cast thin films on silica substrate by spin coating. The films were annealed separately in the vapor of ethanol or toluene over time to induce morphology transformations from spheres, gyroids, and bicontinuous nanostructures, depending on the blending ratio, solvent selectivity, and annealing time, as investigated by atomic force microscopy and X-ray photoelectron spectroscopy. The formation and transformation mechanism of the self-assembly structure are discussed in the context of solvent-copolymer interactions. This study provides new insights into the simple manipulation of self-assembled nanostructures of block copolymer thin films.