Effect of solvent selectivity on supramolecular assemblies of block copolymer by solvent-vapor annealing

Nanoparticles with well-ordered structures have attracted great attention recently due to its potential application, including data storage media, microelectronics and sensors. Herein, we report a strategy of the periodic arrays of iron oxide nanoparticle with supramolecular thin films. The thin films of PS-b-P2VP/FAA supramolecules were solvent-vapor annealed with mixed solvent-vapor condition of toluene: ethanol: water = 9: 1: 0.06 in volumetric ratio. The supramolecular thin film exhibited the structural change of disorder – vertical cylinder – vertical lamellae – mixture (cylinder and lamellae) - cylindrical morphology triggered by the addition of small amount of water due to the change of the solvent selectivity with major block depending on time, leading to the periodic arrays of iron oxide nanoparticle. We expect that this result can provide key information to fabricate the self-assembled naostructure of block copolymers by using the solvent-vapor processing without complicated procedures.